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Forgot to talk about parts.

O-rings. Take your side adjusters and teh 5 bolt snout from inside of the bell housing to a bearing dealer. You need metric o-ings...but can use some standard in a pinch. You need them to fill the grooves by 3/4 to 4/5 teh groove wdith...anticipating compression....fit tight and not protrude over the surface more than about .010". Especially on the aluminum side adjuster rings...if the o-ring is too fat....tehring will shave it off and it will leak worse. You are going to give every o-ring and gasket a thin smear of high temp peramatex copper anyway.

the seals for teh differential side shafts....look at the bores in the aluminum adjuster rings. They make a deep seal and and a shallow seal. You should have deep enough recesses to use the deep seal. Always use teh deep seal....even if you have to have it sized at a bearing dealer.

The main shaft seal inside of teh bell housing. If I had my book...I could gove you a CR brand part #. As it i...go to any CR seal dealer...and they can size you teh proper mainshaft seal for under $8.

Locate some thick..1/16-1/8" gasket paper....not cork...and cut a new gasket for the pan.

Needle bearings. We will take care of the counter bearings with Torlon. The needle bearings that are right past that big ball bearing on teh main shaft I had to replace with two shorter sets of caged needles stacked. A bearing dealer can size them for you. They work perfect. No other needles under the main gears should need replacing. I have never found any that did....nor can you find them anyway. They are unique to the tranny. Just clean everything well.

The big ball bearing rarely if ever gives trouble. Clean the poop out of it. I found out from SKF...that it is unique as well. No replacements...made for NSU.

The synchros are unique...but do not worry. Use the synchro ring to hub gaps from teh bus manual...or from the audi 5000 manual. To make up for a severly worn hub...we can make a brass or delrin shim for behind teh synchro ring. It works well....or you can trade rings from the other tranny. Many times just swapping rings around does plenty well.

The synchro hubs.....are induction welded to each gear cluster....so entertaining thoughts of pressing off and swapping worn synchro hubs will not happen. There is lots more...in order. Be patient. Ray

McMaster rocks! Click links to review material choices:

1" Torlon 4301 - p/n 8566K86

18mm 4140 - p/n 5836T27

1/16 Blended Rubber Sheet Gasket Treated Paper Fiber W/SBR Rubber - p/n 9556K86

Here's where I plan on making grooves in the counter shaft gear cluster ends in prep for the Torlon bushings.




I'll plan on ordering the thicker (15mm vs 9.5mm) final drive seals that fit in the adjusters (p/n 113301189F). I'm waiting on a unbroken spanner wrench (VW182) to arrive before removing the adjusters.


The main shaft seal is type 1? 113311113A

Thanks for all the other tips!

No the mainshaft seal is unique to this vehicle....because the type 004 uses a totally different diameter of mainshaft. This is one of the many typos on the books. Many older parts manuals think that the 004 is the same or similar to the 091. It is not.
Take the old seal...or ..with the old seal out measure teh sealing surface on the shaft and the bore size. Notice....that in the seal bore for the mainshaft...there is a .5-1.0mm step that the seal either seats against or presses dwon past.
You can take the three measurements...shaft, bore and seal thickness to any bearing and seal dealer and the ywill set you up with tehexact seal for very cheap. I can't access the part # right now.

But...if you do a search in the 411/412 forum....the part # is published there.

The 1/16 gasket paper is kind of thick. You should look for non-rubberized 1/32" vegetable parchment gasket paper. The rubber componet compresses to much. Gasket thickness is important. Try NAPA. We will actually add the treatment to seal the surface with the hard sealer...then a evry thin smear of permatex copper on assembly.

For years....I used the original gaskets. I cleaned teh heck out of them by soaking in MEK...then drying...then resealing them. They are very thin.

The slotting areas for the counter gear are spot on. About .040-.050" deep max. Then polish the living crap out of them. Ray

The main shaft seal is CR-6620 (size 17x30x7)(see Ray's post)

My gaskets are in good shape. Any reason not to reuse them? Just soak in MEK overnight, rub, rinse and dry out?

You can use berrymans chemtool to clean the gaskets. The issue is that you want to clean them until there is virtually no oil on them at all. Them when you install...use something out of the permatex ultra line (ultra copper, black ,grey). These stick very well in places where things"could" be oily. I smear them just enough to give color...likepaper thin. Then clamp in place.

Once you get the Torlon bearings made....I am working out the drawings of the mods to make to them to greatly enhance the oiling.....and to pin them in place. You will need a dremel tool to accomplish teh final mods...but they are simple .

basically....you will be (a) sanding a 45* bevel on the ID of each end of these bearings (5) at low speed will a high speed steel ball cutter you will be installing two grooves...180* apart inside....each one only half the length of the bearing ID...and from opposite ends. The end that will go to the inside of the gear cluster.....will also get a triangular "ramp"....that intersects both the ball milled groove and the bevel at the opening.

What this does......is as the bearing (which will be connected to the gear with a pin)...turns around the 18mm shaft.....the triangular ramp scoops oil at an angle....rolling it into the ball milled grovve to keep thing lubricated. The ramp from the opposite end does the same from oil brought in by the three slots you grooved into the shaft faces. Keeping the oiling grooves in teh bearing at 180* apart insures that the oil will not just pass through teh bearing without getting spread on the shaft.

I have found that teh oiling grooves at each end of the gear...along with drilling the center oiling hole larger by about 1.5 mm....and scaloping the leading edge twoard rotation....of that hole...greatly helps the shaft to be submerged in oil inside. This helps a lot even with needle bearings. With modified Torlon plane bearings the lube will be much better. Ray

Something to check if you have not yet started backing the adjuster rings out. Pull teh side seals and re-install the CV hubs with their snap rings. Make sure they go back on the same side...or at least make sure that the split spacer rings go back on the same sides they came from.

Rattle the CV hubs. Do they seem to move around bit? Does there seem to be gap between the spacer ring and the end of the differential housing on one or both sides? If when you pull outward on either the end of the stub axle or the CV flange.....is there movement of the stub axle in and out that is noticable...like more than just a couple thusandths?

If so...this means that either the shim bewteen the stub axle and diff housing inside of the diff is worn (common)...or the outer spacer ring between the CV flange and housing is worn...less common...or both. Either way...it means we will have a few things to measure....when we disassemble the diff....and you WILL need teh Bentley brown book for tyoe 3 to look at both 4 speed type one and 003 auto. You will have to restore the shims ...easy...just swap to thicker ones....and/or also swap a thicker spacer tube in between the shafts. Also really easy. Ray

raygreenwood wrote:The slotting areas for the counter gear are spot on. About .040-.050" deep max. Then polish the living crap out of them. Ray

My machinist friend will cut grooves on a mill with a 3/32 ball end cutter. The gear is very hard. Any other easy way to do it right?

raygreenwood wrote:Something to check if you have not yet started backing the adjuster rings out. Pull teh side seals and re-install the CV hubs with their snap rings. Make sure they go back on the same side...or at least make sure that the split spacer rings go back on the same sides they came from.

Rattle the CV hubs. Do they seem to move around bit? Does there seem to be gap between the spacer ring and the end of the differential housing on one or both sides? If when you pull outward on either the end of the stub axle or the CV flange.....is there movement of the stub axle in and out that is noticable...like more than just a couple thusandths?

If so...this means that either the shim bewteen the stub axle and diff housing inside of the diff is worn (common)...or the outer spacer ring between the CV flange and housing is worn...less common...or both. Either way...it means we will have a few things to measure....when we disassemble the diff....and you WILL need teh Bentley brown book for tyoe 3 to look at both 4 speed type one and 003 auto. You will have to restore the shims ...easy...just swap to thicker ones....and/or also swap a thicker spacer tube in between the shafts. Also really easy. Ray

Checked and found to be tight. Here's wear of the split spacer ring and differential housing.



Another parts question... are these (click link) the differential carrier bearings (final drive side bearings shown in above picture)? Replace them?

If they are listed for an 091 bus....they should be the same.
Good. I would rather have those side rings slightly tight than loose.
Still...when we get there...we are also going to check the wear on the shims while checking the wear on the spacer between the two stub shafts....and inspecting the spyder gears. This inspection is necessary because the spyder gears are one of the weak points....if the shims and spacer tube get worn excessively.

Yes....the gear is freakin hard! Its actually easier to use a good quality triangular file to cut the grooves...then polish with a dremel and 2000 grit. Ray

One thing about inspecting gears. I forgot to mention that it looks like your transmission is in very good shape. You are lucky.

While you are waiting....take a look at the smallest end gear on the countershaft cluster. Look hard in valleys. You want to also inspect tehgear it meshes with on the mainshaft. Look for "spalling" or flecks of metal that look like erosion in the valleys. I suspect you will not find any because your needle bearings had not yet worn into teh shaft...bring teh counter gear cluster out of alignmnet.

If you have a transmission where the small gear has light spalling....you can drive it if you correct the bearings...but its days are numbered to perhaps...70k more miles. It will warn you when it is getting close by starting to howl in fourth gear.

This is why I tell everyone that no matter how well your 004 drives....strip it...and correct things before that gear spalling begins and the countershaft is dead.

The same issue happens in the differential. The 004 has unique (for ACVW) diff spyders. They have very long and deep mesh teeth with a low number of total teeth on them.

Performance wise...this makes for very quick and even cornering under power. Its a higher gear ratio in the differential. But...it means that they are highly loaded and must stay in precise adjustment.

When the outer ring spacer wears out...or is ommitted by unknowing mechanics during a seal change....the side gears will push inward too hard....or more precisely they hammer in and out. This wears out teh flat shim underneath the side stubs inside teh diff....and causes accelerated wear to the spacer tube inside.....causing more hammering of both spacers.
This causes the teeth of the spyders to penetrate too deeply...causing spalling. Once thsi starts...again...50k + miles with no sounds or warnings and the teeth snap off and its all over.

The object is to find teh condition of worn shims, tubes, and spacers before spalling begins and fix it.....because teh spyders cannot be replaced. They match nothing. But...I am working on being able to drop in side shafts and spyders from either an 091....or an auotbox...with light machine work. Ray

I almost forgot to add this stuff.

In many instances...when you read the factory manuals....they tell you how to evaluate parts like bearings to decide wether the part needs to be replaced or not.

Thats a noble cause. When it comes to differntial and pinion bearings its sometimes smarter not to replace them because the prices were high, the labor and resetting of tolerance and lash were high.

But, that was in the days when bearing costs were much higher and they were also envisioning that you would simply check and readjust certain tolerances and drive on....and when the box finally wears out....just go to the dealer and get a new one.

We can't do that now....and bearings are cheap.

When you pull a differential or pinion bearing out....in order to want to not replace it....it should be pristine.
This is mainly judged by inspecting the race. Any lines or grooves...replace it.
There is also the phenomena of bearings that are perfect....butt when the race is wiped off.....instead of a fine mirror finish....the surface looks perfectly smooth....no lines...but has a"hazy" milky reflectance.
That means that this bearing had a great and perfect life...but that now the level of polish has driven the surface roughness up. It will not stand up to teh readjustment of pre-load that you need to do for used versus new bearings when you open the tranny up. It will not too far down the line...start wearing rollers.

Its false economy to not replace the big bearings. The big needle bearings on the other hand....like those on the main shaft....can last for ever.

Here is one big thing that will save money. If your counter shaft looks as good as the one in this build-up.....meaning is has imperfections of color and polish...but no grooves or pits that you can feel.....AND you are going to use Torlon bearings.....you do not have to replace the shaft at all.

Torlon will not even see minor surface polish imperfections. Ray

raygreenwood wrote:OK.... ...You are down to the differential.

...

Once that ring is off:

A few points here before we start on the differential. If you read through the Bentley type 3 manual....in the section for the automatic
not the manual.....and while looking carefully at the differential design of the 004....you will soon see that they are the same full hypoid design....with the same problems. The case is in the way of measureing what you need to measure.....without very special tools.

Do not despair....its not that hard. Just have to get creative. A few things...just like on the differential of the type 003 autobox....are very fortunate.

(1) You can now see...the cast iron pinion carrier. It fits into the case...from the bell housing side if memory serves. It has an adjuster ring in the end...which you can see....and couped with the shim that is under the five bolt carrier inside of the bell housing....will always set the pinion mesh depth to the correct center measurement to the ring gear.

Bearing cover end of pinion carrier

As long as you keep....this ring, pinion gear, main shaft and differential housing, and nose cone seal from the bell housing.... together....with that thick shim with the five bolt holes.....you will never have to adjust the pinion gear to ring gear mesh depth.

The only thing you will have to set....is the bearing preload on the pinion shaft.

(2) At this point....you will be loosening the two differntial side gear aluminum adjustin rings. Before you start.....mark them permanently ...LEFT AND RIGHT. Then....with a sharp, fine punch...mark a 12:00 position both on the ring and on the case. Be very exact about this.

Now....start unscrewing them. Count each turn out...and WRITE IT DOWN. You will always get to a point where the ring comes out.....at less than a final full turn. At the exact point the final thread becomes disengaged....use a dremel or a file....to put a line mark....right at the punch mark.
In this way...each full revolution is from punch mark to punch mark. The final partial turn...is punch mark to line. So when you start turning this back in.....you start with the file line at the punch mark.

Since you will be using new bearings and setting the preload...ao you will probably not be using the old adjustment....but this is a safety precaution in case you have to reassemble it the way it is.

Let me save this and start on a new parargraph.

Side adjusters with o-ring and VW182 tool (tooth width narrowed to fit 004)

raygreenwood wrote:Now...with the adjusting rings out....you will notice that you cannot remove the differential until the pinion shaft and pinion carrier come out.

For this.....you need to strap the case down horizontal. Take a socket, extension and breaker bar...and crack loose the five nuts inside of the bell housing that hold the pinion carrier. You will notcie that when th ebolts are gone...the pinion carrier does not yet budge.

With the tranny sitting horizontal.....slave cylinder hole at the top....like right side up.....look at the bottom...or lower edge of that cast iron flange inside of the bell housing that you just took the five nuts off of. You will notice a ledge...or lug area. With a small "hook" end prybar like a nail puller...levered under that ledge....you will break the cast iron nose cone loose. It will fall out......and in it is the bearing race for the pinion bearing. You use that same pry bar to lever that race out.

Now you can push the pinion carrier and shaft out from the inside.

Bearing cover spacer and o-ring

Pinion carrier bearing cover removed

Make serious note here:

When you buy new pinion bearings...do not do so until you have the old ones off. You will need to do this in a press with proper pullers at a shop.

The reason is.....and I made this mistake.....the bearing that is on the pinion shaft is available in TWO identical part #'s...with different letter codes. The different letter codes denote a different filet radius on the bottom side of the bearing. One works...the other does not.
DO NOT buy bearings until you have the bearing off to read the EXACT part #.

Before you take the adjusting ring out of the pinion carrier you will need to use the dremel to remove the blockage from the factory locking punch mark. If you do not...you will distort the threads on the ring and it gets ugly. Just like the side adjuster rings.....make a punch mark at 12:00...turn until it disengages...and at the final thread....make a line at the punch mark so you have a strting place.

Pinion bearing adjuster ring blocks ground down with dremel

You can now pull the shaft out of the carrier enough to get a puller under that bearing....if memory serves.

Not sure how to get the outer pinion bearing race out...

Do the bearings on the pinion shaft first. You can pull out the differential now.

NOTE:...when you pulled out the aluminum side adjuster rings on teh differential...there should have been a split steel ring spacer on the side shafts on each side...under the seal. They are specific to each side unless they are the exact same thickness. There is some explaining to do about these spacer rings ....I will get to when we talk about the differential and spyder gears. More later...Ray

raygreenwood wrote:One thing about inspecting gears. I forgot to mention that it looks like your transmission is in very good shape. You are lucky.

While you are waiting....take a look at the smallest end gear on the countershaft cluster. Look hard in valleys. You want to also inspect tehgear it meshes with on the mainshaft. Look for "spalling" or flecks of metal that look like erosion in the valleys. I suspect you will not find any because your needle bearings had not yet worn into teh shaft...bring teh counter gear cluster out of alignmnet.

Spalled countershaft cluster small gear

No significant wear on large mainshaft gear

If you have a transmission where the small gear has light spalling....you can drive it if you correct the bearings...but its days are numbered to perhaps...70k more miles. It will warn you when it is getting close by starting to howl in fourth gear.

This is why I tell everyone that no matter how well your 004 drives....strip it...and correct things before that gear spalling begins and the countershaft is dead.

The same issue happens in the differential. The 004 has unique (for ACVW) diff spyders. They have very long and deep mesh teeth with a low number of total teeth on them.

Performance wise...this makes for very quick and even cornering under power. Its a higher gear ratio in the differential. But...it means that they are highly loaded and must stay in precise adjustment.

When the outer ring spacer wears out...or is ommitted by unknowing mechanics during a seal change....the side gears will push inward too hard....or more precisely they hammer in and out. This wears out teh flat shim underneath the side stubs inside teh diff....and causes accelerated wear to the spacer tube inside.....causing more hammering of both spacers.
This causes the teeth of the spyders to penetrate too deeply...causing spalling. Once thsi starts...again...50k + miles with no sounds or warnings and the teeth snap off and its all over.

The object is to find teh condition of worn shims, tubes, and spacers before spalling begins and fix it.....because teh spyders cannot be replaced. They match nothing. But...I am working on being able to drop in side shafts and spyders from either an 091....or an auotbox...with light machine work. Ray

raygreenwood wrote:I almost forgot to add this stuff.

In many instances...when you read the factory manuals....they tell you how to evaluate parts like bearings to decide wether the part needs to be replaced or not.

Thats a noble cause. When it comes to differntial and pinion bearings its sometimes smarter not to replace them because the prices were high, the labor and resetting of tolerance and lash were high.

But, that was in the days when bearing costs were much higher and they were also envisioning that you would simply check and readjust certain tolerances and drive on....and when the box finally wears out....just go to the dealer and get a new one.

We can't do that now....and bearings are cheap.

When you pull a differential or pinion bearing out....in order to want to not replace it....it should be pristine.
This is mainly judged by inspecting the race. Any lines or grooves...replace it.
There is also the phenomena of bearings that are perfect....butt when the race is wiped off.....instead of a fine mirror finish....the surface looks perfectly smooth....no lines...but has a"hazy" milky reflectance.
That means that this bearing had a great and perfect life...but that now the level of polish has driven the surface roughness up. It will not stand up to teh readjustment of pre-load that you need to do for used versus new bearings when you open the tranny up. It will not too far down the line...start wearing rollers.

Differential bearing races with hazy surface


Worn rear pinion bearing outer race located in bearing cover

Its false economy to not replace the big bearings. The big needle bearings on the other hand....like those on the main shaft....can last for ever.

Here is one big thing that will save money. If your counter shaft looks as good as the one in this build-up.....meaning is has imperfections of color and polish...but no grooves or pits that you can feel.....AND you are going to use Torlon bearings.....you do not have to replace the shaft at all.

Torlon will not even see minor surface polish imperfections. Ray

Here's the machine work on the countershaft gear cluster ends for lubrication...


Depth is .050" width is .096". I'll polish smooth next.

It's going well. Thanks for the help Ray!

Looks great! Yes...polish the top edges of each oil groove...extremely smooth. There is a dremel polishing wheel I use for this type of stuff. Its about 1/8" thick....3/4" in diameter and is powdery gray and very soft.

Yep...it was time on the bearings. the wear on the counter gear is not bad. It usually starts because the needles are wearing and its just out of alignment enough. Ray

raygreenwood wrote:Still...when we get there...we are also going to check the wear on the shims while checking the wear on the spacer between the two stub shafts....and inspecting the spyder gears. This inspection is necessary because the spyder gears are one of the weak points....if the shims and spacer tube get worn excessively.

Can you please help with the differential now?

Ok...the differential. Its easier to work with of you go ahead and pull the bearing off the long end so you can lock the diff in a soft jawed vice. You pon't have to lock it hard.

Before you take it apart...you need to read up in the brown bentley typr 3 manal...or any Bentley ACVW manual....about measuring the play in teh differential side shafts.

Just going from memory ...you first lock one side shaft in a vice so you can lift upward...to pull the stub outward...so the gear head on the inside comes up tight against the shim underneath. Then....you can pull/move the opposite stub axle in and out to measure any slack or movement with a dial indicator. This will tell you if the stub has slack between it and the shim or it and the spacer tube.
Then you flip the differential over and measure the same on the other stub.

To have teh stub axles in te hcorrect position to measure the stub opposite....I beleive you will need to put teh outer spacer ring back on...and reinstall the CV flange on oneside at a time..to set the spacing correctly...so you can measure the slack on the other side. I am going off memory on this method...so check the book method.

I can tell you this much already. Since the shim ring on the outside of the stub axles was tight between the diff body and the CV flanges....its an excellent bet that the shims inside....those under the gear head of the side shafts between the gear head and diff housing.....are NOT worn significantly.
So....any in/out movement of the stub axles....will denote wear of the spacer tube inside of the differntial. That is...IF the amount of slack or movement you find.....is excessive according to the book.

The reason you need to measure both sides in this manner is because one side may have moe wear than the other.

It really should be pretty simple.....once the outer spacers and CV flanges are installed....you either have correct slack between spacer tube and side axles or you have excessive slack.

To disassemble the diff.....you need a brass drift and a rubber mallet.

Mount the diff in the vise....marke the cover position and gear location.....and loosen all the bolts. Screw them out a few turns each...then whack them with a rubber mallet. This will start pusing the gear off.
When you get it far enough out from the diff body to get a thin brass drift between gear and cover...stop whacking on the bolts.

You want to first remove one bolt all teh way so you can see how deep it goes into the gear. Reason why....is you do not want to whack on bolts that have less than 5-6 threads into the gear....so they have enough load surface that you do not damage the threads.

When the gear is off....the cover comes off. You can see taht there are two holes on the inside of the cover to allow you to use a puller/drift/punch..to drive off the short side bearing.

Let me know when you get to this point. You want to see how much side to side slack the spyder have on their shaft. Then you can remove the roll pin...and drive out the cross shaft. Ray

This is a great topic!