Front Diff Pinion Seal Leaking

Grip72 · July 18, 2009

just curious if this is hard to do or requires many tools?

i am somewhat mechanically inclined and like trying new things

i have replaced many an alternator, oil change, tranny fluid change, shocks replacement, body lift, levelling kit, replace disc brake pads and rotors/shoes, so if it isn't any more complicated than these i should be ok haha...so is it tough?

and it looks like a minor leak but i'd like to fix it anyways...are they pretty crucial to fix ASAP or are they common and i should ignore it lol

it'd be really nice if not every damn parts store was sold out of manuals for my truck!

alwcurlz · July 18, 2009

just curious if this is hard to do or requires many tools?

i am somewhat mechanically inclined and like trying new things

i have replaced many an alternator, oil change, tranny fluid change, shocks replacement, body lift, levelling kit, replace disc brake pads and rotors/shoes, so if it isn't any more complicated than these i should be ok haha...so is it tough?

and it looks like a minor leak but i'd like to fix it anyways...are they pretty crucial to fix ASAP or are they common and i should ignore it lol

it'd be really nice if not every damn parts store was sold out of manuals for my truck!

I tried to pull the whole differential unit out and replace both seals and found it very very difficult when only on the ground or ramps. Unless you have the truck up on a lift it will be difficult getting in or out. If you're replacing only the passenger side seal, that portion would be the black cast iron output shaft tube. If only replacing that, it isn't that difficult. The diff can stay in the truck as you remove the output shaft/tube. You need to get a Haynes or Chilton book and read it CAREFULLY as to not mess anything up. You'll need to rent some tools from the auto store as well for this. Make sure you keep the level full on that differential in the mean time.

Good luck!

Spurshot · July 21, 2009

Changed mine in my 99 2500 last yr. Straight forward. Mine was hard and dry from heat/age. But, be warned, it's got a crush sleeve between the two Timken bearings to keep them tensioned correctly and the GM manual fix shortcuts replacing the crush sleeve. Some people disagree with not changing the crush sleeve after loosening the pinion nut, but GM put a procedure together and put it in their manual.

Buy the Helms/GM manual for your truck and the procedure is in there. Follow it. If you don't have the Helms/GM manual for your truck, you should get it. It's the best money you'll spend for servicing your truck and will save you more money and time than you paid for it, the first time you use it.

This job is pretty easy and could take as little as 30-45 minutes if you have all the tools and everything goes well. I struggled for at least that long just trying to pry the seal out with improper tools.

Chuck

Grip72 · July 21, 2009

hmm

yeah i'll only have ramps/jackstand and probably have to rent tools

gmtech4 · July 22, 2009

remove the driveshaft,get a socket for the pinion nut,mark the nut and flange with marker for reinstallation,remove the nut ,get a seal remover ,pop it out and tap in a new seal ,reinstall clean flange (if not grooved to bad )tighten the nut and align the marks ,reinstall drive shaft.

now if you can do that and not blow up your pinion bearing costing alot more than the seal get a pro to do it,there is a crush sleeve in there and if over tightened ,your diff is toast,ka ching

Mark the nut and flange or ching ching ,top up the diff

oh and have fun,dealer charges roughly an hour

ADber is talking about the axle seals ,disregard his post

alwcurlz · July 23, 2009

I would follow the Helms/GM manual and strongly disregard gmtech4. He's missing too much information and leaving out important instructions. He doesn't understand what you are trying to accomplish.

Spurshot · July 23, 2009

There are a couple very important steps missing above. Before removing/loosening the pinion nut, check the rotating force with a small torque wrench. Record that number. When tightening the pinion nut, you'll need to check the rotation force often after the nut has pulled all the parts together against the crush sleeve. It's not rocket science, but you only get one chance at getting it right . If you over torque it and the bearing is too tight, the diff is not "toast", but the crush sleeve will need changing. That means pulling the cover and removing the ring gear carrier, etc.. Don't worry, it's actually harder to overtorque than this explanation would have you believe.

It's not all that hard to get it right. It takes a tremendous amount of torque to crush the sleeve. You will feel the nut seem like it bottoms out but the pinion rotates freely. You just made solid contact with the crush sleeve. Torque the nut just enough that you felt the nut turn. But a little turn and then check it for torque... and keep going until the torque is 3 in/lbs more than the rotating torque before you took it apart. That should be about the first little bit of tightening after the crush sleeve is felt. You'll be amazed at the torque required to tighten the nut that little bit more.

gmtech4 · July 23, 2009

i didn't mean to offend you adber ,I read it over again and he wanted a pinion seal replaced not axle seals and I have done a thousand of them ,anyways ,take it easy will ya