Engine/Transmission (1994 - 1998) Rear pinon seal leaking. Need part #'s and advice to change it.

[LWilliams]

I noticed my rear pinon seal leaking last night. I have done a search here but did not find much on advise or part numbers. I can probably stumble through it but it would be nice to have you guys experience before I start. Any help would be appreciated. Thanks.

 

[Extreme1]

I did my own and here's my recomendations (I'm sure others will chime in).



First, be abolutely sure there is no play in the bearings supporting the pinion. Check with a dial indicator. Usually the bearings are loose allowing the pinion to moove slightly which takes out the seal.



Assuming it's just the seal, and, since your truck has a Dana 80, you'll need the socket to fit the nut under the driveshaft and a very strong inpact wrench. The torque on the nut is 450 ft/lbs, the best way to get it reassembled correctly is to mark the nut and the flange and get it a little tighter. The bearings are seperated by machined spacers so this method is acceptable on this rear end.



You will also need a puller to remove the flange from the pinion shaft. It seems that Dana didn't think 450 ft-lbs would do it by itself! It can be tapped back on far enough to get the nut started when reassembling.



As for the seal itself, it's a normal light press, use a good seal compound on it.



It's best to drop the lube level while you're replacing the seal so the new seal sealant sticks to the housing, you might as well change it too.



I hope this helps.

 

[LWilliams]

I've located a seal for $18. and I have a 3/4 impact. I've talked to several people that have done this as well as two shops that have always done good work for me. I do not know about the seal compound that you mentioned though. What is it and where is it applied?

 

[Bob4x4]

There is a sealing compound already applied to the od of most brands of seals that will be suficient. Maybe I have been lucky but in all the Dana 80 pinion seals I have replaced I have not found any with loose bearings. You might consider filling the area of the seal where the seal spring resides with grease to help minimize the chance of the spring comming out during assembly.



Bob