I pulled my driveline today to replace the rear shaft seal and found that the shaft has a bit of play in it. I am guessing this is not normal and there should be no movement at the rear shaft spline that meets the driveline? Any help is very appreciated.

 

Without the yoke in place there will be some play in the rear shaft.

 

Perfect. Thank you. I had no odd noises or vibrations so thought it may be possible to be normal. Just wasn't sure if the play was the cause of the seal leak. Thanks again.

 

What type of rear end? What model of car? We need specifics to guide you in the right direction, can't assume its a 65 JetStar.

If I'm interpreting correctly you are asking about pinion axial play or pinion gear to ring gear lash?

See pic of 68 motors manual for the spec

If you are replacing the pinion seal be aware when you reassemble the preload is critical. Do you have the proper tools, torque wrenches, and a dial indicator? You may need a new crush sleeve(if equipped). If the pinion has a deep enough groove worn into it, installing a new seal won't fix the leak. You need to install a speedy sleeve over the pinion seal surface. If that is the case there is a trick to this to get good results. Ask if needed.

If the gears are good Id simply perform a full rebuild using new USA made bearings, seals crush sleeve etc...If you are not confident on how to do this have a reputable shop do it. Get it wrong and it will lead to disaster.

 

Actually, I thought he was talking about the rear seal and output shaft of the transmission with the yoke out.

 

He never said which one.

 

Yes. 1965 Jetstar. Here are the numbers on the rear differential. The output shaft seal at the transmission where it connects to the driveline yolk is where I am attempting a new seal.

 

The car appears to be a Jetstar I and if so the trans is a Turbo 400.

 

There's the clarity we needed...

Then yes play at the output shaft this is normal once the driveshaft yoke is removed.
This is do the fact that the yoke slips over the trans shaft splines and the OD of the yoke rides on a sleeve bearing in the tail shaft. Once the drive shaft is reinserted you should have minimal deflection at this location.

Be sure the yoke surface is clean and smooth. Hit it with crocus paper(very fine grit sandpaper 800 grit...ish). If it has a deep groove that you can catch a fingernail in it needs to be replaced or speedy sleeved.

Always salve up the yoke with trans fluid before insertion into the trans(inside and outside).

Tip: Careful prying out the old seal. You can easily damage the tail shaft housing.
Pack petroleum jelly(NEVER grease) behind the seal. Why...to capture the seal tension spring. This aids in keeping the spring in place when you (carefully) insert the driveshaft assembly into the trans.
Now is a good time to service the trans fluid and filter.

 

Your a better thinker than I am Eric. The description was to vague for me. Sounded more like a pinion seal to me. That's why we always ask for detailed information. This thread could have been a two post thread had the OP been crystal clear.

 

that iquote s the OP. But thanks for the warm welcome and great tips.

 

which was answered in the first response.