Engine/Transmission (1994 - 1998) Rear pinoin seal

[Flinty]

I'll be replacing the rear pinon seal on my Dana 80 here directly. The manual says 450-500 ft-lbs of torque on that thing. Any advice before I tear into it will be much appreciated. BTW, what's a good additive for the limited slip? Thanks.

 

[bmoeller]

Basically, make sure everything is clean, and you might need to use a puller to get the yoke off.

An impact wrench will be the best to remove the nut. I'd probably stick a pry bar between the ears on the yoke, so it won't be hammering on the gears.

If it uses the nut with a nylon insert, replace it. Do not reuse it. They don't always stay tight after removing them.

Make sure the shaft and seal area don't have a burr on them to scratch/cut the new seal.

 

[JGK]

Also, inspect the yoke shaft where the seal rides once you pull it out. If the seal is leaking, its failure often leads to a groove into the shaft. On mine, the groove was so smooth and perfect it looked like it belonged there. It was about the size of a pencil line on paper. If it's grooved, you need a new yoke. About $150 +/- from the dealer.



Given the cost of the yoke and seal, plus the tools needed to remove and replace and the torque on the nut, I opted to just let the dealer do it. Labor was right at an hour. No diff fluid lost so no expense there. For me the cost of them doing it was cheaper and easier than me writhing around under the truck for an afternoon.



FWIW,

-Jay

 

[Woodenhead]

I second the use of an impact to get the nut off. The first time I did mine on my '89 we used my buddies impact and it went fine. We managed to tear the seal when we put the yoke back on so I had to do it a second time. This time I had no impact and finally ended up using a 3/4 drive socket on a bar with a piece of pipe and a 4' pipe wrench to hold the yoke and keep the wheels from turning. There's not much room to swing a long handle under there and it really sucked.



Mike

 

[Extreme1]

The only tricky part is getting the pinion flange off. Torque spec is 450 ft lbs. Yes 450 - not a typo.



Mark the nut's relationship to the pinion shaft. Use a big impact. You need a puller to remove the flange. Change the seal. When you reinstall the pinion flange nut, turn it just a touch past where it was. This is how I did mine. My friend whose shop I was able to borrow part of (A drive on lift) just shakes his head at me and says "Glad my customers don't have stuff this big".



If there is a groove in the pinion that you can't polish out (mine came out OK), get a Speedy-Sleave.

 

[Flinty]

Well, I finally got this task behind me. I had to buy a new yolk as the old one had a groove worn in it. I had to have my socket machined down to fit in the new bore and I had to build a tool to press the new part on to the pinion shaft. When I tried to force the new yolk on to the shaft with the nut it would only go so far and then bind up. I attribute this to the fact that I was trying to push and twist at the same time. It took time to think through the physics, and even more time to wait for my wife to get back in town, but I know it's done right. Plus I got to spend lots of time with my babies.

 

[Coalsmoke]

Its too bad you bought a whole new yoke. For future reference, for about $20 you can put a speedysleeve on, use a backer of red loctite and you're good to go. This is not a backyard farmers type repair, its done by professional shops on a daily basis.

 

[Bart]

Coalsmoke has it right. They have thin stainless steel sleeves for yokes, axles almost everything that has a seal riding on it. Info for next time.

 

[Flinty]

I considered the sleeve option but didn't know about the extra thin part. IMO, in a pinon application the heat generated by the extra space the sleeve takes up can cause premature seal failure. For others that find this thread does any one have suppliers/manufacturers or part#'s for this "thin sleeve"? The cheapest speedy sleeve I could find in these parts was $40, the seal was another $40 so for another $140 I got a brand new fix with no band-aids from Quad 4X4, this included a new nut, washer, u-joint straps and bolts, yolk, loctite for the nut and a good quality seal. Not chump change but for a little more than a tank of fuel it's done right. Well, it's all about options, that's what makes this site and the folks who pay to be on it so appealing. Good info and food for thought. Thanks.