Replacing Rear Pinion Seal...

[TheRob]

So, it looks like the pinion seal from at the rear diff is leaking. This is a 1999 2.5L with the 7.5" rear end. I've searched on here and some people seem to say it's not that bad while others say it is one that's prone to error. Can someone point me to a walk-through on this job, if it exists, or let me know the critical points where I could make an error? I read about problems with the pinion nut (not sure where that is...oh boy) not being torqued correctly, but someone else had quoted 180 ft-lbs and red loctite when reinstalling. Also, someone had cautioned about not damaging the pinion bearing when removing the seal. So far, here is how I think it goes:

Remove rear diff cover and drain fluid. Unbolt "crossbolt" that holds the pinion in (not sure which that is, but it should be apparent, I think). Slide the pinion back partially out of the diff. Remove pinion seal with a "hook-type" seal puller (any more details on that?). Install new seal and reverse the process.

Not sure where the pinion nut comes into play in this or what its function is. I'd like to get it lined up as much as possible in my mind before I try this job, so any details would be appreciated.

Thanks,
-Rob

 

[Toms01PSD]

To be completely honest and not a dickhead, if you don't know what the pinion nut it I wouldn't dare attempt to do it. The pinion nut is exactly that, the nut that "holds" the pinion. After you remove the driveshaft it's clearly visible. Here's a picture I found:http://www.off-road.com/trucks4x4/data/articlestandard/chevy/442007/469459/gear_4.jpg

 

[TheRob]

...

Ahh, that makes sense. And I appreciate the concern, but if I never try to get anything done that I'm not quite sure about, I'll just never learn anything new. To be honest, this is the third car in the family and if I break it, it's ok. It's definitely not something I HAVE to rely on, thankfully.

That was a very informative picture, so thanks for that. When removing the pinion nut, do you have to put the car into some kind of position or condition to provide something to torque against, or will the wheels being stopped on the ground just do that alone?

Thanks again,
-Rob

 

[Toms01PSD]

Whether it's something you need or not, i'm sure I still wouldn't do it. I'm not sure if you'd have to set everything back up as i'm sure you have to pull out the carrier because I don't believe the pinion will slide out even with the spider gears out. There are certain things where I would say hell ya go for it to learn it, but differentials are a totally different ball game and take practice and repetition to understand and install correctly. Wait a little longer and i'm sure someone with more experience will chime in and correct me if i'm wrong.

 

[4x4junkie]

Take a look through the Axles FAQ here, there are some links that will explain in detail the process of setting up (swapping) and working with rearend gears.
It's not overly difficult as long as you have all the right tools and knowledge, but lacking either one is almost a guarantee for disaster.

The biggest thing will be to make sure you reapply the proper preload on the pinion bearings when you reassemble it after replacing the seal.

 

[TheRob]

...

Tom, thanks for the advice. It definitely seems like rear ends are a special breed of problematic. I'll take a look at the FAQ and get some more knowledge in the head before considering it. It seems like it's not leaking too badly, as I cleaned off the residue and have been watching it as I drove around today, so it seems like it can at least wait a bit.

-Rob

 

[Toms01PSD]

Ya, i'm not trying to be a dick or anything. I'd just hate to see you put work into something difficult and get caught up on something and have to pay to have it towed and pay someone else to do it. I'm in the same boat. The only difference is I have my shop teacher to help me install my gears and do all the setting up so i'm not going into it blindly. If you do give it a whirl, good luck!

 

[Explorin94]

If you do just replace the pinion seal you don't need to reset the drag of the pinion, unless there bearing is bad. If the bearing is bad then you need to go through the whole process of resetting the gearset again. If it is only the seal you'll need tools to remove the driveshaft and an impact to get the nut off. The yoke pulls right off, pry the seal out, install the new seal, clean the yoke where the seal rides, install the nut back and torque it to 60 foot pounds. Done. No rocket science here fellas.

 

[85_Ranger4x4]

The pinion nut is what sets the preload. You can't take the pinion nut off without effecting the preload.

It isn't rocket science but you can screw a lot of things up if you do it wrong.

You have to pull the carrier out to check the rolling resistance of the pinion with bend beam in/lb torque wrench. Have a helper with a prybar wedged in between two bolts (I used some generic ones to pry on, not the pretty 12pt ones that Ford used) in the flange to hold it still while you tighten it. You have to have the carrier/axles/tires off so otherwise there is nothing to keep the pinion from just spinning. It has been a couple months since I did mine, but I think the book gives 60 ft/lbs as a starting point and then adjust from there to get the right rolling resistance.

If you overtorque it you may be on the market for a new crush sleeve... which put bluntly WILL ruin your day.

And remember it is better to have a bearing run a little too loose rather than a little tight (towards the bottom end of the range they give you)

The tough part is finding a book that has instructions on how to do it. My Ranger Haynes just says how to pull the carrier, so does my dad's F-series Chiltons. Dad has a book for working on my uncles 1980's E-250 that actually had detailed instructions on how to do it.

 

[Sasquatch_Ryda]

If you do just replace the pinion seal you don't need to reset the drag of the pinion, unless there bearing is bad. If the bearing is bad then you need to go through the whole process of resetting the gearset again. If it is only the seal you'll need tools to remove the driveshaft and an impact to get the nut off. The yoke pulls right off, pry the seal out, install the new seal, clean the yoke where the seal rides, install the nut back and torque it to 60 foot pounds. Done. No rocket science here fellas.

No its not rocket science, but if you over tighten the nut you will crush the crush sleeve which will put too much preload on the bearings.

Approximate torque required to tighten pinion flange nut to obtain
Correct pinion bearing preload (if bearing preload exceeds specifications before this torque is reached a new collapsible spacer must be installed)
is 160ft lbs.

 

[Explorin94]

The pinion nut is what sets the preload. You can't take the pinion nut off without effecting the preload.

It isn't rocket science but you can screw a lot of things up if you do it wrong.

You have to pull the carrier out to check the rolling resistance of the pinion with bend beam in/lb torque wrench. Have a helper with a prybar wedged in between two bolts (I used some generic ones to pry on, not the pretty 12pt ones that Ford used) in the flange to hold it still while you tighten it. You have to have the carrier/axles/tires off so otherwise there is nothing to keep the pinion from just spinning. It has been a couple months since I did mine, but I think the book gives 60 ft/lbs as a starting point and then adjust from there to get the right rolling resistance.

If you overtorque it you may be on the market for a new crush sleeve... which put bluntly WILL ruin your day.

And remember it is better to have a bearing run a little too loose rather than a little tight (towards the bottom end of the range they give you)

The tough part is finding a book that has instructions on how to do it. My Ranger Haynes just says how to pull the carrier, so does my dad's F-series Chiltons. Dad has a book for working on my uncles 1980's E-250 that actually had detailed instructions on how to do it.

The pinion nut does not set the preload of the pinion it holds it, the crush sleeve is what sets the preload of the pinion. If just replacing a seal the crush sleeve already has the preload set along with the drag of the bearings, if the bearing does not have to be replaced. It takes alot more than 60 foot pounds of torque to crush the crush sleeve. Therefore torquing the pinion nut to 60 foot pounds will not hurt nor mess with the preset load of any part of the pinion bearing. It will just I have done this for quite a while and have never has any pinion bearing failure what so ever.

 

[scotts90ranger]

over a year ago I replaced my pinion seal without taking the axle apart, just pulled the seal and put in a new one, didn't torque the nut to anything specific (my pinion bearings were loose anyway), I don't care about my axle so I just did it... the bearings are toast and the gears are somewhat chipped so yeah...

 

[4x4junkie]

The pinion nut does not set the preload of the pinion it holds it, the crush sleeve is what sets the preload of the pinion. If just replacing a seal the crush sleeve already has the preload set along with the drag of the bearings, if the bearing does not have to be replaced. It takes alot more than 60 foot pounds of torque to crush the crush sleeve. Therefore torquing the pinion nut to 60 foot pounds will not hurt nor mess with the preset load of any part of the pinion bearing. It will just I have done this for quite a while and have never has any pinion bearing failure what so ever.

Yes it does...
60 ft-lbs is nowhere near enough to restore proper preload on the pinion bearings.

Like Sasquatch said, the minimum is more like 160ft-lbs on the nut if you're reusing an existing crush sleeve (it usually takes in excess of 250ft-lbs to crush the sleeve). 85_Ranger is also correct that you must check the rotational preload of the pinion with the carrier removed as well. Not doing any of this is simply taking a gamble that your rearend doesn't fail.

 

[ajshades]

Not to dig up an old post but what's the real answer here?

I recently replaced the seal and bough a new flange so I don't have a mark to follow.

Will 60lbs do the job or does it need to be 160?

Should there be space between the gray part of the flange and the seal/rearend?