Seals for automatic tranny

[wildthings]

I just tore down the automatic transmision out of my 72 411, with the intention of resealing it. Everything out of the gasket/seal set fit right except for the sealing rings for the second gear band actuating piston. The seals in the kit for this piston are too small in diameter. My tranny needs sealing rings for 3 inch and 3 3/4 inch bores. Has anyone else had this problem. Does anyone know a source for the correct sealing rings, or the brand of a rebuild kit that contains the correct size rings.

[MGVWfan]

I just got to the teardown phase on my 003 AT, I'll let you know if I find the same problem with the seal kit Makco sent me.

[MGVWfan]

I've got the same problem ...I'm calling Makco on Monday morning.

BTW, did your kit have only one pinion shaft seal? Mine has one, and you need two. Another thing to ask about.

BTW, they did a great job finding a set of bands and clutch plates for me, so I'm hopeful the piston seal thing will be solvable.

[MGVWfan]

First question...Hey Ray, does your big book of part numbers have a CR or National (or whatever) number for the 003 AT pinion seals, VW P/N 003 519 085?

Second question...what is the best seal material for this application, ATF on one side, EP gear oil on the other, temps up to 220 deg F? The seals in the kit are probably some generic synthetic rubber (nitrile?), which may be OK, but would something like Viton or silicone (or PTFE?) be better? I'm asking because I'm missing one pinion shaft seal from the kit, and if I can get a better quality seal locally, I'll do it, and use it for both seals. They're hard to get to, so a real lifetime replacement would be worth the extra bucks.

BTW, I measure the seal dimensions as 30mm ID (shaft OD), 40mm OD (housing bore), and 7mm thickness, single lip, spring-loaded, rubber cased, in case Ray or DB can cross that over into something useable.

[raygreenwood]

Sorry...no go on the part #.
Yes....the seal composition issue you are asking about....is the granddaddy problem for all auto gearboxes....be they Porsche, VW, Audi, Volvo etc.
I do onot know if they have solved this on modern front wheel drive trannys....which have the same problem. It would suffice to say that they either have....or they still have the same problem.

So....until I learn what the new car seals are made of....here is the warning. ALL would do good to heed this.

If you drive a European car...VW Audi, Volvo etc....with an automatic, you MUST take it out every 7 years or 70K miles and put a seal kit in it. If not....100% of ALL of these trannys are nothing but junk waiting to happen. It does not matter if the care has "0" miles on it original. If its over 7 years old....the tranny is junk until resealed. If its brand new and has gone 70k miles in one year....tough....its junk until resealed.
There are no lifetime seals...yet...to my knowledge.
As MGVW had brought up....these seals were a compromise. There was at that time (and may still be now)...no rubber compound that stood up 100% to both Hypoid oil and Dexron III. So the lifespan was limited.

When this seal fails....the loss of the tranny will occour within ...maybe 5 miles. It wil be ugly...complete...and catastrophic. Like...lots of broken parts internally...and wheels locking up. Ray

[MGVWfan]

The way some manufacturers lessened the impact of the problem (specific to transverse FWD) was to change to helical gear drive for the differential, and use ATF in both the transmission and the differential section. No need for EP lube when you don't have a hypoid final drive. No need to seal the transmission output shaft, since both sides use the same lube. It does cause more wear on the ring gear, but the trans still goes 150K miles without excessive wear in most cases.

BTW, I nicked one of the seals on the forward clutch while I was trying to put the piston back in, so I can't reassemble the trans until I get a replacement

[wildthings]

Here is another number for the seal between the tranny and differential: TTO D2126 70144 don't know if this will help you cross it or not.

As for what oil to run in the differential section, I ran ATF in the manual transaxle on my '87 Synchro for about 100,000 miles. I later switched to 0-30 synthetic motor oil and have put about another 45,000 miles on it. There is no seal between the differential and tranny sections on a manual so what ever oil is in the tranny is also in the differential. The total milage on that gear box is now close to 295,000 and it seems to still be going strong. The previous owner had put about 150,000 miles on it running 90wt, but by the time I got it you could hardly get it to shift anymore, it was either find an oil that would allow the synchronizers to work right or fork over a few G's for a rebuild. At this point the transaxle owes me nothing, but it will be interesting to see what the ring and pinion look like if it is ever torn down.

I've been around a lot of equipment that runs ATF in hypoid gear boxes, and so long as the oil level is high enough this doesn't seem to cause much in the way of problems. I have seen several pieces of equipment where early models ran 90wt in the hypoid boxes, but later models ran ATF or other hydrualic fluids. Usually the only difference in the gear boxes was the height of the fill plug.

I am thinking of running 10-30 or 10-40 synthetic in the differential section of my 003 when I put it back in.

[raygreenwood]

The synchro s a totally different animal. Also...what were the climate conditions where you ran ATF in your manual bxes or in hypoid differentials? Short of arctic conditions, you should never run ATF in a hypoid set. Hypoid gearing has the highest level of shear forces and sliding galling forces available. Its the trade-off for running long silent lives.

Most auto trans and/or manual trans that run other than hypoid oil....are NOT hypoid gear sets. They are standard skew bevel or straight cut gears.

I have been on the receiving end of three 003 trannys that have died of the seal fealure syndrome.....and have been on the "helping to repair/autopsy/replace" end of about ten more VW/audi auto boxes that died of the same failure.

Its also worth it to note, that yes....the manual boxes run on the same oil end to end...both differential and transfer case. But.....there is not a single part in the transfer case section of an auto box that is related to whats in the transfer case of a manual box ......and.....its not the transfer case section of the automatic that gets destroyed when the two fluidx mix during a seal failure. Its the differential.....from dilution of the hypoid oil.
Its also worth it to note, that usually.....usually....the differential fails before the transfer case has time to fail....but on the occasion when it does not, the transfer case section will eventually fail. This is due to the heavy oil choking the valve body and the pump section. It starves for oil. It also clogs any transmission cooler system you had. These two oils do not mix. Ray

[wildthings]

If you look at a standard involute gear you will see that the greatest wear occurs at the pitch line, the exact point where the shearing and sliding is the minimum. Journal bearing don't wear precisely because there is a lot of shear/sliding. Shearing and sliding do not necessarily transmit into wear. This being said hypoid gears can produce a lot of heat which must be accounted for or disipated, this is where the actions of hypoid oils and hydrualic oils is very different. Hypoid oils must in general live with the heat, as there is only a small amount of oil in the contact area between the gears, whereas hydrualic oils are run at a high oil depths and tend to flood the contact zone and thus disipate the heat quicker.

At low speeds with heavy loads hypoid lubes with EP additives will probably usually be the winner, but at high speeds and lower loads whatever oil cause the gear box to run the coolest will more likely give the longest life. I am not recommending that anyone switch their differentials or other boxes over to non-hypoid oils, I am just stating that it worked well for me in the case of my Synchro transaxle which was already having lubricant problems at the time I switched it to ATF, and that in other applications where the manufacturer recommended ATF or other hydrualic oils in hypoid gears sets there have been no problems. I have also run 5-30 synthetic in my 72 Transporter's manual transaxle for the last 50,000 miles because it makes for easier shifting than GL-4 did.

People tend to be thick in the head when it comes to oil, especially they all to often think that the thicker the oil the better, even though thicker oils often generate more heat, wasting out seals and gumming up everything inside a gear box. They also like to think that newer is better than older, which is why a lot of VW manual transaxles which are supposed to run GL-4 lubes have been messed up running GL-5,6 lubes. A lot of these people have never been bothered to read the manual either.

[raygreenwood]

I agree in a lot of areas...the GL-4/GL-5 issue...yes. The heat issue...yes. Running too thick of an oil...yes....BUT....ATF Vs Hypoiud ..has nothing whatsoever to do with thick or thin. They are simply different oil bases. One is EP...one is not.

Flooded versus non flooded on hypoids....no.
The hypoid differentials...most especially the ones in question , most certainly run (with correct oil levels) to about just below mid-level on the differential, covering the first window in the differential body. If not, the spyders starve. The oil climbs the gear and flys..yes, but they generally run flooded.

The ATF...hydraulic oil as you correctly put it...has "0" extreme pressure additives to prevent galling. ATF...also has a lower smoke/soot point and break down temperature than hypid oils.

I agree on where the wear and tooth contact point occours...but thats not really the issue when the wrong oil is used. The metallic bases many of these hypoid oils run....or polymer in the case of synthetic hypoid oils..... are what keep these oils from breaking down with age, keep them from breaking down with temperature...and most importantly, keep them from "shear thinning" at the pressure points on the gear teeth... wherin and because of....the sliding surface speed from tooth to tooth/ring to pinion....is far higher and therefore generates ...shear higher..... than the shear points available from a hydraulic oil.

That "shear"....creates heat (which hypoid oil CAN handle...hydraulic cannot) . When the hydraulic oil is put in the position of a hypoid.....at normal temperatures (not arctic),.....shear thinning quickly drops the viscosity to the point where metal to metal contact happens.

Not trying to be argumentative.....but there just is no "good" purpose for substituting ATF for hypoid oil ...short of arctic conditions...wherin there is little if any heat build-up...and therfore no shear thinning...and therefore ATF works in place of hypoid.

One thing also to remember. The standard bug /bus /thing/ghia/type III....standard transmissions...are NOT pure hypoid designs. And......this may be why you are getting away with ATF in place of hypoid (if you are getting away with it).

The transmissions in question here...those being purely the automatics for rear engine drive (oo3 and oo3 variants and the type 004 four speed for type 4)...... ...not front drive...or front engine, front tranny rear drive. Those have gearing just like the bug/bus etc....four speeds .

For those that do not know what I am speaking of...let me see if I can illustrate.
In say...a bug tranny...or even an 091...in fact all 4 speed rear engine VW trannys except one......IF...you look at a cutaway of the differental section, bell housing to your right, tail cone to your left...you will notice that the pinion gear contacts the ring gear at the 9 0'clock position. This is skew bevel gearing. The spiral cut of the ring gear, is but one feature of true hypoid gearing (but not the only feature)....BUT the CONFIGURATION...is NOT hypoid. With the normal bug pinion at 9'0clock....you get simplicity of casting and position...making the tranny less complex, and you get reduced friction and heat as the tooth contact pattern......IS....as wildthings noted....in a position to give relatively low surfface pressure as it mostly slides. But...bear in mind that this gearing is at a straight tangent to the ring gear. It is also noisier and rougher than a pure hypoid design.

Now.....take the same cuta-way, but of the auto-box differential, on any ACVW, including the type 004 four speed. What you will see is that the pinion shaft crosses UNDER the differential on the gear side.....starting at about 7 o'clock position, ending up making gear mesh at approximately 5:00 position.
THIS is a true hypoid design. It is an offset, tangential, skew bevel gearing. It has much different tooth geometry than the standard bug/bus trannys. It also has very long tooth contact time in two different dimensions with the ring gear. This gearing....will NOT live with ATF...unless it is very cold outside. Ray

[MGVWfan]

NEWSFLASH ON THE SEAL FRONT

Makco pointed me to Precision International, their supplier of 003 trans parts...

http://www.transmissionkits.com/foreign ... on-kit.htm

I didn't get to call them before COB today, I will call tomorrow. Their site does only list one pinion shaft seal as coming in the kit, even though you really need 2, so that explains that. As for the 2nd gear servo piston seal problem, an old parts book I got off E-you-know-where solved that mystery. Drum roll for Wildthings and I please...

THERE ARE TWO SIZES OF 2nd GEAR SERVO PISTONS!!!! One used up to Ch # 410 2021 954, one from 410 2021 955 on. The early piston seals are 68mm and 86mm diameter, the later ones are 77 and 97mm diameter (two seals on the 2nd gear servo piston). It would appear Wildthings and I received kits with the early size seals. I just measured the servo piston in my trans, it's the later size (77/97mm), which confirms the parts book. I'm calling Precision International tomorrow to see if there's a fix. I'll post what info I come up with.

Does anyone have similar info on the early transverse WCVW AT's servos (not Dasher/Passat, it used a 003 early on)? I'd almost bet that VW just slightly modified the gearset section of a 003 for the gearset section of the AT they put in the early Rabbit/Golf. Might make finding seals easier.

[MGVWfan]

Well...I just looked at the 010 transaxle in a Mitchell manual in the library, and it's very different from the 003 trans. However, it does have one band servo, mounted on the outside of the case, so next time I'm at the junkyard, if I see a VW/Audi 010 transaxle, I'll see if the seals are the same as the ones in question.

Precision International was not helpful at all. Bulkparts is swapping over their website, and some of their suppliers right now, FYI. They are asking their suppliers if they have the seals in question, so we'll see.

I priced a Viton pinion shaft seal, $30 with shipping ( ouch!), so I'm considering if it's worth it to go with Viton, or just stay with nitrile.

[vwbill]

Hey, have you tried talking with Stuart at Street and Sand Toys(in the vendor listings)? He has been doing VW's for a long time! Maybe he has a source or can suggest a match if you have those dimensions?? Bill

[MGVWfan]

Latest on the seals...I got a package from Makco last night, and it had the correct seals in it. It's the same P/N Precision International kit, but it was assembled later, and has different labelling on the bags inside the kit. In the "Misc. Components" kit was the seal we need for the later 003's 2nd gear band servo piston. So, moral of the story, call the place you got the kit from, if it's Precision International, they have a "Misc Parts" kit that they (should) be able to provide your supplier. You'll have to make sure you've got both the "SUB-K401, 2ND GEAR (KICKDOWN) SERVO" sub-kit as well as the "SUB-K404 MISC. COMPONENTS" sub-kit. 401 has one of the two seals you'll need, and 404 has the other. I'll also be posting some parts sources for the 003 AT in the sticky thread on this forum.

BTW, I recommend TransJel Gold (Makco sells it) for assembly as an assembly lube. It made stuffing the forward clutch servo piston back into the drum a snap (along with guiding the seal in with a 6 thousandths feeler gauge).

[vwbill]

That's great you found a parts solution! Need to add that one to the vendor list! Thanks for the posts! Is it worth it to the auto guys to buy doubles or is it a once its right thing? Bill