Gearbox problems...?

[Lars S]

Got her home last night!


The (manual) gearbox was working OK when previous owner last drove it 22 years ago, no noise or shifting problems. He had a mechanic to open it (and the engine) just to check and change gaskets etc. Nothing special was found and it was properly put together (i trust) and have been resting indoors for some 20 years.
Now, when turning the flanges for the output shafts the movement is not even (no gear in), there is a bit of uneven resistance just like a roller bearing being bad.
Picked out the diff, the resistance and quite a bit of noise comes from the 4 small gears inside the diff so no roller bearing is involved. Some oil did make it a bit better but not much.

Is this a problem and in that case what to do about it, or is it normal?


/Lars S

[Lars S]

...just want to add that I also have a 411 gearbox on the floor to compare with, yes I can hear the theeths from the diff when rotating the shafts but the rotaion ican be made even and requires less power..also there is more play when between the two shafts in it (the 914 box has minimal play).

It feels like the 914 one is a bit to "tight", the theets wants to stick a bit now and then, what can it come from?


/Lars S

[Piledriver]

Check the oil, change it on principle, Swepco 201 or 203.

It has been sitting for 22 years, I suspect some parts of the trans may be a bit dry...

After 22 years I would consider opening it up and have a look.
(The rubber seals will probably be toast anyway)

[Lars S]

Thanks Piledriver,
I took the diff out, cleaned and re-lubed it - much better but not good.
Possibly the PO has shimmed the diff to hard since the resistance comes from the 4 small gears in square, (shimming is possible to these diffs?)

When it comes to repair , what parts are still available for theese gearboxes, not many Im afraid...?


/Lars S

[Type 4 Unleashed]

Thanks Piledriver,
I took the diff out, cleaned and re-lubed it - much better but not good.
Possibly the PO has shimmed the diff to hard since the resistance comes from the 4 small gears in square, (shimming is possible to these diffs?)

When it comes to repair , what parts are still available for theese gearboxes, not many Im afraid...?


/Lars S

I don't think you have a problem. If you spin one of the out put flanges, the other one spins the opposite direction via the 4 gears, and their shouldn't be that much drag. But if you turn both flanges in the same direction, you are now turning the the carrier with the ring gear which in turn turns the gear stack which is mostly dry of gear oil, other than what was used for re-assembly. And if you were to put it in gear and turn the 2 out put flanges in the same direction you will have even more drag.

So when you turn one out put flange and the other turns in the opposit direction, that is all your turning, your not turning the carrier or the gear stack.Try turning the out put flange by it's self, then both together the same direction for comparison.

And as for repair of the 901, there are plenty of parts, good used & even new. But new stuff isn't that cheap.

[412s2]

Great looking project Lars, are you going to tell us more about it?

I am rather envious!! Good luck!!

[Lars S]

412S2,
many thanks for the attenion and enviousity...
I have posted some info in this thread, more will come...trust me..

http://www.shoptalkforums.net/viewtopic ... 2043aa1c7e


/lars S

[Lars S]

Have now had a pro gearbox mechanic (with true VW and Porsche education from the 60's) to look and feel at my gearbox - no problems, it only has little wear and play and therefore feels stiff - good!

Putting the differential back in the housing:
1. what torque should I use on the 10 nuts in circle of the final drive cover?
2.What torque on the central (expansion) bolt for the final drive flange shaft?
3. Should there be some loctite on this bolt? (looked like there was when i took it off...)

Asking because I have found a few different torques in different sources...


/Lars S