problems with the rear diff

purpleTJchick

purpleTJchick

Well-Known Member
Joined
Apr 6, 2005
Location
Durham
First off, I have an 8.8 in the rear, lockrite locker, and 4.56 gears

While in VA I had a hole in the diff, So I jbweld putty the diff so I could get back to base camp. it came apart and the hole got bigger a few yards from camp so I just left it there and went wheeling with the rest of the group. It was trailered home so I was OK.

Now, my problem. The hole was made from the inside. 4 bolts came out of the ring, and the "teeth" pushed the bolt into the diff cover, which lead to a hole. 3 of the 4 bolts were damaged. and 3/4 of the teeth are fine. I have yet to be able to see the back of the teeth, so I do not know what type of damage I am going to have.

I assume the guy that put the rear in the Heep did not put the bolts to torque, or locktite them. My Q's are what is the correct torque for the bolts, and is it OK to use locktite? Also, assuming the teeth are not messed up what Else should I look for as far as damage goes?

Also... if my terminology is wrong (I am sure something is wrong) just give me a picture and I will tell you what I am talking about.
 
Dayam. Did a shop do this to you, or a friend?

If "3/4 of the teeth are fine", then 1/4 are screwed up? IMO, it won't run long if you just bolt it back up as-is.
 
8.8 problems

This must be a common problem with the 8.8. It happened to a guy a couple weeks aga at DPG. Ring gear bolts came out and punched several holes in the cover. Actually made swiss cheeze out of the cover.
 
Backyard machinics (not only me, few others that build there own rig)....

I am not planing on running it at all if the teeth are messed up. which pretty much means more backyard machinics.

I was more or less asking if the teeth are fine, what esle should I look for to be messed up. if I have to redue it I want everything to be done right, which means I need to know the torque settings. any idea where I can find this at?

Depending on the price I might concidered having a pro do this.
 
bits and pieces of metal can be lost in the bearings....if you run the same bearings.....you may be back in it again. Another hunnert bucks in bearings now, or risk pulling it apart again, again. :( If nothing else, be very anal about cleaning and flushing everything.
 
The 8.8 stock open carrier is VERY VERY weak, you should check that it isn't actually cracked. That is why many people swap in a ARB or detroit.
 
Something else to think about...

The spider gears in the standard 8.8 diff are prone to getting chewed up under normal use. My neighbor (old guy) tore up a set under normal driving conditions in a 2WD. It is an older Lightning, but I doubt he ever gets it much over the speed limit.

I guess I was lucky in my old f-150, as I never had any axle trouble front or rear out of the 8.8's. Belive it or not, I've never busted the 8.8 in my very modified 5.0 Mustang either. Transmissions....well that's another story. :rolleyes:

Opps... Just re-read the orignial post and you already have an aftermarket locker... never mind.
 
Ring gear bolts on an 8.8 - 60 foot lbs. Yes, use red Loctite.

If it were me...... (Being the cheap bastard I am) I would pull the cover off, and clean out any metal chips. Flush it out with oil, brake cleaner whatever. Get the rear up on jackstands have someone rotate the wheels and watch and listen for what is going on with your contact areas (locker and ring/pinion gears). Be sure to engage/disengages your locker. While doing this feel for any "kinks" while rotating the wheels. Listen for grinding/popping. If you can detect any of this, I'd get a new gear set, bearings, and all new ring gear bolts. If you detected anything in your locker, take it apart and visually examine it. If it looks OK (It may be possible to file out a small burr if there are any.), put the locker back in and retest it by hand again. If the locker is still grinding/popping/binding (other than its normal popping from the springs), it's probably junk.

But, if everything seems to be operation smoothly, I'd still most likely install new ring gear bolts. 1 at a time so you don't take a chance at unseating the ring gear. To make sure the ring gear is flush to the carrier, use a .002 feeler gage. After you install your new cover/ replace the oil, Get on it hard in your driveway. Not necessarily spinning tires on dry pavement, but get on it. Try in in 4WD also (more torque to the axles). If something is gonna give, it will most likely happen then. If it seems OK drive it for 250 - 300 miles, pull the cover and reinspect again. If all seems well I wouldn't worry about it. Theres no guarantee on this, but you might be OK.

This is all assuming your gears were set up properly.

But, when you damage the ring/pinion teeth - odds are you'll be replacing you ring/pinion/bearings.
 
You drive this Jeep Daily right? I'd pull it apart, or have someone who knows rears pull it apart and inspect it. If it was a trailer queen, I'd wouldn't be as worried about not completly inspecting. But as it's your DD too....

Bill (44MagnumOffroad) is just north of you about an hour. Axles are his specialty. and he'll give you his honest opinion of what he'd recomend and what he'd do if it was his Jeep.
 
IF you can rotate the axle and the teeth are undamaged after installing and torquing new ring gear bolts. I would run it.

I have seen 2 8.8s do this and both were retorqued and ran. (1 came apart on a wednseday, was retorqued and ran thru sunday at telico with anew cover)

If it backs out it is possible to smoothly lose contact with the pinion (though Id never be lucky enough for it to happen to me), also look over pinion teeth.
 
mbalbritton said:
You drive this Jeep Daily right? I'd pull it apart, or have someone who knows rears pull it apart and inspect it. If it was a trailer queen, I'd wouldn't be as worried about not completly inspecting. But as it's your DD too....

Bill (44MagnumOffroad) is just north of you about an hour. Axles are his specialty. and he'll give you his honest opinion of what he'd recomend and what he'd do if it was his Jeep.
Click to expand...


not a daily driver, but if you knew how anal I can get you would think it is

thanks for the info on 44mangum, I might need it.

Rob, thanks for the link!!!
 
UPDATE:

I finally got parts in to take the jeep off the trailer.

Damage report...

3 teeth seemed to be shaved a tad on the inside edge. I checked it the best I could. it does not seem to grind or anything seems differnt about the way it works. The lockers seem ok, but I have not fully looked at them that much, yet. bearings seem ok too.

Personally I was freezing my ass off from playing in the water trying to clean the mud and diff fluid off my trailer, so I did not stick around to long to examin the damage very good. I left it jacked up off the ground and put the old diff cover back on to keep some dirt out of it. (yes, it is in the garage)

sorry for the crappy pics, not only a picture phone, but a nextel

oct07_001.jpg


oct07_002.jpg


oct07_003.jpg
 
Sounds/Looks like you might be OK. Get some new ring gear bolts, red locktite, and check the torques on the carrier caps, and I wouldn't be skeert.
 
To add, when you do the locktight, spray brake cleaner or something that will break down the 90w into the holes, and blow dry. locktight ain't worth a hoot if there is oil inside the holes.
I am not someone who knows how to set up gears, but have watched a time or two. I know installers will put a type of grease on the gear and rotate it, so that they can see a wear pattern or contact pattern. Might be worth doing this to make sure.
Luck to ya
 
I never heard about the breakcleaner in the bolt holes, Will have to do.

Also, the grease is yellow right? I can pick some of that up also.

As far as the bolts go I was only able to find 7 grade 8 7/16 fine thread, I think I needed 8

Thanks for the help guys!
 
Go to you local autoparts store, or 4wd place, get ring gear bolts. The gear oil is yellowish and reeks..

Ditto on cleaning the threads
 
the teeth that are ground some, appear to be to allow you to slide your center pin out without having to remove the ring gear.. Thats a common thing to do..

The yellow stuff is paint...
 
haha, let me rephrase that, I know what gear oil is haha, I wanted to make sure the "marker" type grease you use to mark the gears are yellow :p
 
Check the teeth on the locker also . If they are worn a little now would be a good time to pull it out, file the teeth slightly on the edges and rotate the left side gear to the right and the right to the left. Trick I learned from an old white haired man who use to linger around these parts and it made a difference in my LR with almost 300k on it:huggy:
 
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