late 915 transmission input shaft seal installation

[William Miller]

My input shaft seal needs replacement.
This is on a later type where the seal is pressed into the guide tube.

Bently Manual suggests pressing it in from the engine side of the tube. My question is how far is it supposed to go?
On the transmission end of the guide tube it seems the internal diameter of the guide tube is just a hair smaller. This area is about 1/4" from the transmission end of the tube. Is this where the seal is supposed to stop? I installed it before flush with the end of the tube in the transmission. I'm thinking that is possibly caused the problem.

Please no guesses.
I wish I had a picture to post!
Thanks anyone who can help!

[William Miller]

Here's a picture of the tube from the transmission end.
There is a very slight reflection of where the diameter gets smaller.

[john walker's workshop]

it sits in the smaller diameter area. i use a factory puller and installation tool that sets the flat face of the seal in 40mm from the outer end.

[William Miller]

Thanks JW!
Thanks! I have a deep socket that is a perfect fit. I'll mark it 40mm.

I have a new o-ring for the grove on the outside. Do you ever use any other type of sealant? I was thinking maybe a tiney bead silicone RTV.

Possibly a bad idea since sometimes the tubes are not that easy to remove.

Thanks again!

[William Miller]

Sure it isn't 45-50?
On mine 40 just get's it to the smaller part, but not seated inside it.

[blue72s]

Not trying to hijack the thread but did the 901/911 tranny have a boss in the bellhousing like the late 915 transmissions?

thanks.

[john walker's workshop]

some of the later ones went in deeper. i just measured my factory tool. if 40mm gets it all the way into the smaller ID part, then it's 40mm. if not then press it in with a socket until it completely enters the smaller ID part and no more.

[john walker's workshop]

yes, some of the later ones went in deeper. i just measured my factory tool. if 40mm gets it all the way into the smaller ID part, then it's 40mm. if not then press it in with a socket until it completely enters the smaller ID part and no more. i was thinking that 83 should be the shallower one.

[William Miller]

I pushed it in about 50mm. The backside of the lip is almost even with the inside edge of the tube. It sits centered in the area where the tube is slightly smaller. It looks like it is where it is supposed to go.
When the tube was installed the lips sit pretty much centered on the area of the input shaft where it's supposed to seal.

So in this instance I think 50mm is the right answer. 40mm would just get ot to the smaller area but not inside. The seal would not stay in place.

Thanks for your help. We'll see if it leaks shortly!

I'm sooooo lucky I have the tube that is removable.
Asside from R&R the engine this was a 10 min job with really no special tools.

[William Miller]

Update and new info.
About a week after the above post, my clutch disintegrated on T3 at Summit Point. The lining on the pressure plate was completely shredded. The flywheel side was still OK. The little strands of the friction material were all over the place inside and outside the bell housing.

Before dropping the engine I ordered a new clutch kit and guide tube/ seal.
The new guide tube had the smaller ID at 40mm like JW mentioned above. So I installed it that way. Now it's nagging me.

The old (Deep) setup had the seal lips on the wide OD area of the shaft. The new (shallow) setup has the inner lip sealing on that wide OD area of the shaft and the outter lip on the thinner OD area of the shaft (Very close to the transition. The seal looks like it was made to do this because the inner lip has a bigger ID than the outter.
Does this make sence.
Seems like it would be easy to get these mixed up when ordering parts.
I think that was probably done and what caused the leak in the first place.

Any wisdom?