chopper_man

Morning all,

There's about 10 million posts out there about changing the rear flange, there's a fast way and the "right way".

Fast way, pop off, put on new and tourque it down to 150ft/lbs.
"Right way", measure existing in/lbs of preload before taking off the old, install the new by matching the preload which usually brings you to around 150ft/lbs.

I definately prefer the "right way" and there is one thing thats confusing me. They say to measure the existing inch-pounds of preload it takes. Is that pre-load how many in/lbs of torque it takes to spin the entire assembly including the axles? Or is it refering to if you had it totally apart? Or is it something totally different? Would prefer not to totally have to disasemble everything!

I basically got 2 8.8's, one with 3.73's from my old 4.0 and one with 3.31's from my new GT. Going to put the one with 3.73's in this weekend and will need to change the flange.

Anything else I need? I see a lot on mentions of the crush sleeve....Where is this crush sleeve? Internal to the diff or between the flange and the diff? Does it really need to be changed?

Thanks!
-Brian

tx_zstang

The in-lbs is what it takes to keep it spinning once you get it started from a stop.

Get a new pinion seal, too. Crush sleeves are cheap (you can buy a pack of 2 for like $3-4), so do it right and replace the pinion seal and crush sleeve; it is internal, behind the oil slinger washer and pinion bearing. When you remove the pinion flange, you'll see the slinger, which is loose and you can pull out, then pull out the small pinion bearing (loose as well), then reach in with needle nose and get the crush sleeve.

Use a new pinion nut with red loctite as well, torque it down until you feel the crush sleeve stopping you, then keep going until the preload is right (8-12 in-lbs I believe for a used setup).
You dont really have to replace the crush sleeve, if you measure the existing preload before taking off the flange, then get the preload at least that tight upon reinstallation, so there's no slack there in it.

People have 'gotten by' with the fast way, but since you're looking at the right way, do it right all the way. Kudos to ya, and good luck.

(And you will need an INCH-POUNDS torque wrench, likely a 1/4" drive, and an adapter to fit 3/8 or 1/2 for the socket to go over the pinion nut, so you can measure the preload).

Good luck.

doctorstrobe

The pre-load is measured with just the pinion gear installed. The Axles and Diff carrier have to be pulled to do that... It's possible someone has a torqe spec for the proper pre-load with the diff and axles installed, but I've never heard of that...

I don't understand what you say below. You have 2 8.8's...
Do you mean the entire rear axle or just the gear sets?
I'm pretty sure the rear axles in the 4.0 V6s are 7.5" rear ends...

From what I remember, the crush sleeve installs onto the pinion gear before you install the pinion gear into the axle housing, so to change the crush sleeve you have to pull the pinion gear out. That's why everyone hates crush sleeves...
The crush sleeve maintains the proper bearing pre-load through the life of the rear-end.
You're not supposed to re-use a crush sleeve, but who really knows... Maybe it will cause the pinion bearings to fail early?
Plenty of people have changed their pinion flange for single piece drive shafts and they don't change the crush sleeve... How long do you plan to keep the car?

chopper_man

My 4.0 had an 8.8 w/3.73's in it, I put it in about a year ago. i traded the 4.0 last week for a GT, before i traded it I put the original 7.5 back in it. The GT's rear has 3.31's in it. Planning on swapping the 2 rears this weekend and will need to change the flange on the one with the 3.73's in it because it has the cobra one on it now since it was in my 4.0.

I think I may go with measuring the current preload route. I really don't want to open them if I don't need to. I have a 1/4" tourque wrench that does in/lbs.

Can anyone else please confirm it is the force it takes to keep in moving? I'll do it with the calipers removed and axles in. Should give us a decent baseline for anyone else doing it in the future.

avengence

I have seen people try to change the flange by taking off the pinion nut and then pulling off the flange and putting the new one on and torquing it down. DO NOT DO THIS.

You must replace the crush washer after loosening the pinion nut. You might as well do it right if you are going to do it. So either take it to someone or do it yourself. Just my words of advice.

Also like someone said above you should change the seal while you are at it too. Also make sure the preload is correct after doing it.

tx_zstang

Measure what it is with the axle fully assembled, and you'll see what the 'preload' is now. This will lets you learn and see how it can be measured.

When I did the pinion flange swap on my current 8.8, I measured the preload with the rear end out, no wheels, but axles and carrier in it, assembled, but before taking out the flange. This gave me the current preload, even if the axles and all were still on it.

And no, you DO NOT have to pull out the pinion gear to replace the crush sleeve; just the bearing at the flange end needs to be pulled out, which is easy to do as it slides in place over the pinion gear (the bearing race does not need to be removed for this).

I've worked on both 7.5 and 8.8 rear ends, and the procedures are the same.

Root66

If I was going to go as far as replacing the crush sleeve I'd go with a crush sleeve eliminator, takes a little longer to set the preload but it saves time if you ever have to loosen the pinion nut again.

brunobluto

Another thing to consider is if you do use a new crush sleeve, It will take like 250- 300 ft lbs to crush it enough to obtain the 16 inch pound, give or take an inch lb or two, of pre-load. Re-using the old one will require much less force because its already been crushed, obviously. Now if you plan on doing all this in your driveway with the rear end jacked up, It would be extremely difficult , if not impossible to apply that much torque while laying under your car. Even using a cheater bar, you have very little space and you would be in an awkard position. I would just re-use the old crush sleeve following the already stated procedure, and you should be fine.