How hard is to change the pinion seal?

**JayTA98** · 07-07-2010, 05:59 PM

Im starting to see small drops of differentail fuild on the ground. I can see the it looks like is leaking from the pinion seal. I checked the fluid and it seems to be in the normal levels. How hard is to replace the pinion seal? i have some tools but no air tools.

**00ls-1** · 07-07-2010, 07:13 PM

not hard at all pull your driveshaft and the yoke. you might be able to get a screw driver in and pry the seal out if not try driving one side in and the other side should push out...drive the new seal in with a socket or something like that to keep the new seal even can be done approximately 30 minutes

if the seal doesnt come one of those two ways drive a self tapping screw into the seal careful not to go through it too far and it will give you something to pry on

**Knight** · 07-07-2010, 07:29 PM

Also, remember to check your gear oil fluid level - I would just drain and replace it myself - new oil never hurts.

**JayTA98** · 07-08-2010, 03:58 AM

how about the torque specs for the nut? Alot people mark it and count the turns etc. Any good write up on this?

**00ls-1** · 07-08-2010, 05:00 AM

I just put it on with an impact haven't hurt one yet

**JayTA98** · 07-08-2010, 05:35 AM

i dont have any air tools.

**Knight** · 07-08-2010, 05:42 AM

Since you're not replacing the crush sleeve for the pinion gear - I'd mark the nut or threads and retighten when reassembling. If I remember correctly, if you use a torque wrench, I think it ends up being around 150 ft. lbs.

**Street Fighter** · 07-10-2010, 06:20 AM

Originally Posted by JayTA98

how about the torque specs for the nut? Alot people mark it and count the turns etc. Any good write up on this?

Don't use a impact wrench, there is no way you can tell how tight you are getting the nut, always count the threads, once you are back to where you are surpose to be on the pinion, go just a little more . always use lock tight on the threads. Try to use a torque wrench, In case you didn't have one is why I said do the little turn more,many times you will find that over time there will be some wear, so the extra little bit more will do the trick.

**blue02Z** · 07-10-2010, 08:28 AM

you guys all have good advise but your ways are gonna make him overtighten his pinion bearings. get a chisel and make a notch on your pinion shaft and make another lining up with it on the nut. its best to have an impact to remove the nut but you can use a big wrench. take off the nut, use a puller to remove the yoke, then use a screwdiver or seal remover to remove the seal. clean it up, make sure the sealing surface is not gouged up then tap in the new seal. its also best to get some liquid teflon and put on the pinion splines because fluid can seep thru the splines. make sure you tap the yoke on to be sure it is properly splined. tighten the nut down till the yoke stops sliding down on the pinion shaft. get your original marks you made lined up and go maybe 1/8'' more tight on the nut, that usually sets the preload back up right. fyi there is no torque on a pinion nut. there is a rolling torque that just when the pinioin shaft is installed without the ring gear. you put a in/lb torque wrench on the nut and watch how much "rolling torque" is on the bearings. 27-30in/lb is about right. but that is only with just the pinion in alone. hope this helps

**Firebirdjones** · 07-10-2010, 08:51 AM

Originally Posted by blue02Z

you guys all have good advise but your ways are gonna make him overtighten his pinion bearings. get a chisel and make a notch on your pinion shaft and make another lining up with it on the nut. its best to have an impact to remove the nut but you can use a big wrench. take off the nut, use a puller to remove the yoke, then use a screwdiver or seal remover to remove the seal. clean it up, make sure the sealing surface is not gouged up then tap in the new seal. its also best to get some liquid teflon and put on the pinion splines because fluid can seep thru the splines. make sure you tap the yoke on to be sure it is properly splined. tighten the nut down till the yoke stops sliding down on the pinion shaft. get your original marks you made lined up and go maybe 1/8'' more tight on the nut, that usually sets the preload back up right. fyi there is no torque on a pinion nut. there is a rolling torque that just when the pinioin shaft is installed without the ring gear. you put a in/lb torque wrench on the nut and watch how much "rolling torque" is on the bearings. 27-30in/lb is about right. but that is only with just the pinion in alone. hope this helps

This is correct. Setting up a rearend correctly requires the pinion to be set before any other parts are installed. Pinion bearing preload is measured in inch lbs. of rotational torque. Usually about 30 inch lbs. on new bearings.
But it's only 12-15 inch lbs. on used bearings. Which is what we are dealing with here now since you are changing a pinion seal after the fact.

Problem though is you cannot accurately check rotational torque with the rearend assembled, so proper pinion bearing preload is only a guess now. Which is why changing pinion seals can be tricky. Too much preload upon reassembly will take out the pinion bearings down the road, and that not only takes out the seal and causes another leak, but it will require a complete tear down to repair properly.

What Blue02 here mentions is about right. Mark the nut and the pinion. Upon reassembly you will want to tighten about 1/8" passed your mark.

Also keep in mind something that hasn't been mentioned. Make sure you clean the splines on the pinion and the yoke and apply a sealer on the splines before sliding the yoke back into place.
This is also a source of leaks and sometimes it's mistaken for pinion seal leaks when in fact it's coming through the splines and dripping off the pinion nut. I see alot of rearends that come in leaking like this, where they have been rebuilt without sealer on the splines.

If it is infact the seal leaking, you will see oil behind the dust cover and everything if front of that will be dry. If the nut is wet,,,it's coming through the splines.

**JayTA98** · 07-10-2010, 10:10 AM

Thx for the replies guys. I'm putting this task on hold until i get more info and check if its leaking from splines or seal. I think is from the seal. i dont think the rear had service and the car just hit 100k. I hope my rear end last me for a while. I try to take good care of it. I check the fluid level at least once a month. I hardly do hard launches.

**Camaro69Mac** · 07-10-2010, 02:59 PM

Just noticed mine is leaking today, my exhaust had some fluid on it on the front of the rear end. guessing its the seal also. I'm sure it has alot to do with going to the track alot recently also having it lowered and not installing my adj panhard bar so thats screwing up all the angles. Should of learned by now to do this stuff right

**JayTA98** · 07-10-2010, 08:37 PM

anyone know how often we need to replace the fluid in the stock rear end?

**Firebirdjones** · 07-10-2010, 09:14 PM

Depends to me on whether it has that gear type locking unit or a simple clutch unit.

The clutch units I go as far as 30,000 miles. But those gear type lockers create a ton of shit over a short period of time. Shit as in metal shavings. I really don't care for them at all but people seem to like them.
I change the gear oil in those types every 10,000 miles. And I still get a substantial amount of fine metal out of it every time I change it in my 02. My 2000 doesn't have it,,,and it stays relatively clean even after 30,000 miles. It's really up to you.

**blue02Z** · 07-11-2010, 10:34 AM

Originally Posted by Firebirdjones

This is correct. Setting up a rearend correctly requires the pinion to be set before any other parts are installed. Pinion bearing preload is measured in inch lbs. of rotational torque. Usually about 30 inch lbs. on new bearings.
But it's only 12-15 inch lbs. on used bearings. Which is what we are dealing with here now since you are changing a pinion seal after the fact.

Problem though is you cannot accurately check rotational torque with the rearend assembled, so proper pinion bearing preload is only a guess now. Which is why changing pinion seals can be tricky. Too much preload upon reassembly will take out the pinion bearings down the road, and that not only takes out the seal and causes another leak, but it will require a complete tear down to repair properly.

What Blue02 here mentions is about right. Mark the nut and the pinion. Upon reassembly you will want to tighten about 1/8" passed your mark.

Also keep in mind something that hasn't been mentioned. Make sure you clean the splines on the pinion and the yoke and apply a sealer on the splines before sliding the yoke back into place.
This is also a source of leaks and sometimes it's mistaken for pinion seal leaks when in fact it's coming through the splines and dripping off the pinion nut. I see alot of rearends that come in leaking like this, where they have been rebuilt without sealer on the splines.

If it is infact the seal leaking, you will see oil behind the dust cover and everything if front of that will be dry. If the nut is wet,,,it's coming through the splines.

that why i mentioned the liquid teflon. thanks for the backing firebirdjones. i just didnt want to see another thread in a month or 2 asking "what is this growling noise in my rear end"