91.5CTDBanks

Well, I have put new pinion seals in the rear in 2 years and now after only 5 months the second one is leaking again. What could cause this? Thanks.

RuralCruiser007

Is there a groove wore in the pinion flange? With time there will be a groove worn were the seal rides on the flange. You can see the mark even on brand new flanges after little use. Use your fingernail and run it down the flange sealing surface, if it is bad then you will feel the groove. If that is the case then get yourself a speedy sleeve from your local parts store and install it.

On another note, is the spring for the seal still sitting where it belongs? I have had a few springs come off when installing seals. To keep this from happening I now fill the area on the back side of the seal with grease. This keeps the spring in place and also makes sure you have a lubricant at the seal right away.

Benjamin b2

did you put silcone on the splines?

Kansascrewcab76

I bet I can solve this for you...don't waste your time worrying about a grooved pinion.

Rear axle vent is plugged, guarantee it! Pull the hose off and pull the vent/brake tee bolt from the axle and clean it out, a 1/4" drill bit works great.

You might have to change the seal again, but it will be the last time.

bigredbrick

Both of the above plus silicone around the recess the seal fits in. I had a leak there on a Dana 44 in my old Scout.

MoparMarv

Try the vent first see if the leak slows or stops. My rear pinion seal started leaking bad over labor day weekend. I was able to keep an eye on the fluid since I had the mag hytec cover with the dip stick. Got it home and routed the vent to the plug in the mag hytec cover which i never did went I put it on. It didn't stop the leak. I changed the seal and its been dry since.

Kansascrewcab76

Like I stated earlier this is more common that you'd think

91.5CTDBanks

Thanks guys. I will try that this weekend before I drive it.

91.5CTDBanks

Yep, clogged vent. I feel sure I did not need to replace the last one. Also, I used RTV on the housing flange on this last one. This plugged vent probably blew out the first one two years ago.

Kansascrewcab76

I guarantee it did!

Firstgenfanatic

I am trying to find out what rear pinion seal I need for my Dana 70 rearend? The truck is a 1993 with the 3:54 gears. I noticed that the seal replacements are based on the ring gear size. Any part #'s? Thanks

Firstgenfanatic

Anyone?

rustydeeretech

i just went up to napa and told them what i have and they had what i needed you can look at rockauto.com and see what they list