rear gear problem / question

[mysticclam]

The ring gear bolts on my 8.8 backed out after less than 700 miles since installing some 4.56s One of them was hit by something which slammed it into the diff cover and cracked it. I only noticed when i came out to my truck at lunch and noticed oil dots all over the back of the truck. Took it to a shop because I thought the cover was just leaking and they showed me what happened. They are of the opinion that whoever set it up over or under tightened the bolts. It was a friend of a co-workers boyfriend who did it for cash (he races mustangs and has apparently done a lot of 8.8s) I didnt get it fixed because they said if it need a new ring and pinion it would be 1400 bucks which seems excessive. They thought maybe they could just tap the threads and use new bolts and not have to set it up but I didnt like the sound of that. I talked to the guy who set it up and he says "I remember doing it right" and that its broken because I "MUST" have put it in 4wd with the 3.73s still in the front. Yeah, in tacoma on the street I used 4wd. I disconnected the 4wd computer and verified it wouldnt go in BEFORE I took it to him anyway. It was a cash deal so I don't even have any proof he did it so I dont have any recourse.

So, if everything looks ok, which the shop said it did (other than the one ring gear bolt stripping some threads when it got ripped the last bit out) what would be the saftey risks of just retapping the one and retorqueing them all? I worry about it happening again and taking out a c clip or something on the highway.
PS, the gears have never made any noise either so I assume they were otherwise setup correct. If the cover hadnt cracked Id probably still be driving it.

 

[IZwack]

Wait so are you saying that some of the threads on the ring gear are stripped? If not, I would just take brake cleaner to it (to get rid of the oil), squeeze on some red lock-tite, and retorque to spec

 

[CDW6212R]

Ditto, if there is enough of the thread meat still there, I'd see about getting a tap to clean them. Use plenty of red loctite(several drops) on that one bolt, and make sure that they are all torqued correctly.

Isn't 75ft.lbs. the right spec for those ring bolts, I don't recall? If the others are close to the 75ft.lbs. needed, just torque them, and do the single bolt to try to get the same torque. Good luck,

 

[IZwack]

Isn't 75ft.lbs. the right spec for those ring bolts, I don't recall?

Yeayeah - "Ring Gear Bolt to case Ft. Lbs. 70-85"

 

[CDW6212R]

Cool, I was thinking 75-85, but asking is better.

 

[mysticclam]

yeah the threads in the ring gear were stripped on the bolt that ripped out, ill have to pull the cover and look to see how far down, id think not too far if the bolt was out enough to get caught. They were all lose to the point that you could turn a wheel and the carrier would start to move then the ring gear. Also, that thin toothy wheel (ABS ring?) is slightly damaged, I think I can straighten it out though, replacing It I beleive means removing the carrier. Id rather not even do that.

Im sure it would hold at least for a while, i mean I drove it 2 miles home from the shop and all they did was tighen the bolts so its missing one. And no locktite or anything. Also, the crack is near the top so they said it was still 3/4 full when it got to them.

My fear is just losing an axle or having the diff lock up on the highway or something.

I might try this as a short term solution and then start looking for a cheap axle that I can put a set of gears in myself. Im sure it will take me "forever" to long to have the truck immobile so I cant use this axle. Maybe I can find a disk brake axle while im at it. No, probably too expensive.

The real problem is I have a new baby due in a couple weeks and we'll be single income for awhile.

 

[IZwack]

I forget how many ring gear bolts there are on the 8.8 but it might no make much of a difference with one missing -- just dont race anyone though. Actually, you might consider putting that missng bolt back on just for balance during highway driving cauz that one bolt might prematurely wear out the carrier bearings if the entire assembly is not balanced well.

 

[mysticclam]

Whats the best way to fill the differential? I don't want to spring for an expensive cover with a fill plug so im going to just get a recking yard one. Any 8.8 cover will fit?

 

[IZwack]

Yeah any 8.8 cover will fit.

To filll the diff, there is a plug on the front side of it (front of the casted center section, slightly behind and above the pinion flange, on the driver's side) -- takes a 3/8" socket driver. Unscrew that and fill away.

 

[mysticclam]

Well, took the cover off today and found that not one, but 3 of the ring gear bolts are missing. Two holes on the ring gear look slightly damage just near the top, Im going to assume the bolts were damaged and thats why they are not back in. The 3rd hole on the ring gear is wiped smooth about 3/8 of an inch down and the threads look pretty good the rest of the way. I moved a good bolt into that hole and it took 75lbs of torque so Im thinking there is at least enough thread left to hold the bolt in. I think Ill get new bolts all around and put it back. Should be good enough that I can at least move it out of the garage onto the street and stuff. Pretty sure Im looking at a new ring gear in the future though. Sad because neither the ring or pinion has a any visable damage. If fact, all I could find was a nick on the housing where the bolt head must have hit and its amazingly tiny. I cant even find the "crack" in the cover. I think it may have just leaked due to no gasket (only some sort of sealent) being used. Its a plastic one so I may scope out a metal one at the junkyard, if they even made them metal.

 

[CDW6212R]

To replace the gear is all about those thread conditions. If they are usable than the gear is okay. The covers aren't always leak proof. The key is removing all debris, and all burrs. Make both sides completely clean, and use an Ultra RTV, black or gray or copper or blue, the Ultra Black RTV is the cheapest.

Clean out the whole housing well, I'd pull the axles and also wipe out the housing tubes, check the bearings/seals. Good luck,

 

[mysticclam]

I went to the pull a part in the heavy rain today, couldnt find a new cover but got some ring gear bolts off a 7.5. They had 3 or 4 bronco IIs but no explorers. If the rain hadnt been so bad I might have taken one of those tire carries off a BII, they are cool. I think Im going to reuse my old cover for now and order a steel one online or see if I can get one ebay. Do I use the sealant and the gasket or just the sealent?

 

[CDW6212R]

You could use a gasket, but really everyone uses just the sealant. Covers are easy to find, any 8.8 cover can work. Find a Mustang V8 or F150, most will have the 8.8 in them. If your cover isn't broken you can keep it. Is it aluminum, most were steel, and the aluminum units should break if damaged?

 

[mysticclam]

Its plastic, no kidding. The only damage is near where the bolts go in, it looks like damaged fiberglass, Its just a nicked spot on the inside, I just don't see how it could have anything to do with leaking as it doesnt go through the cover and it doesnt make the gasket surface uneven. I just have to find the fill plug now.
My gut is telling me this all should work out ok. I cant see how a bolt even if it came out again could get to the teeth side of the ring gear as it almost completly seperates the two halfs of the case. Ill replace the missing gear bolts, locktite them all and torque them to spec and check again in a few hundred miles, I should have a steel cover by then too.

 

[IZwack]

If you have a welder, you could tack the ring gear bolts to the carrier to ensure the never back out again. Even thoug the carrier is cast, a quick tack should work as heat effect is minimal so you shouldnt need the hi-nickel stuff.

 

[Albino 94LTD]

Tim, if you need another 8.8, I have a drum brake one with 3.55's in it that you can have. I was going to put it in my Bll But I doubt that'll ever happen.

PM me if you want it.

 

[mysticclam]

My axle is good, its really just a question of if the ring gear bolts will hold and I'd like to get a steel cover but those are cheaply available on ebay.
Thanks though. Too bad about your BII, the guy accross the street has one that just sits there and I keep thinking, man if that were mine id be totally driving it. They are cool little trucks. If I didnt have a sentimental attachment to my Explorer, I think Id sell it and try and find a BII, or at least an Ex Sport. The yard I went to had 3 BIIs. I think Im going to go back and nab the tire carrier off one of them. Dont know if it can be made to fit an explorer or if it can even hold a 33 but they are cool

 

[mysticclam]

100 miles so far and no noises or anything. Seems to be working. Turns out the cover is cracked after all, its at the top, one of the bolts must have been overtightened as the crack starts in the hole and goes about half an inch into the cover. It only leaks when driving because its above the oil level. I gooped some RTV over it and that slowed it down. I think Ill drive it a couple hundred miles and then pull the cover to check everything and put a steel cover on. Got one coming off ebay.
So im into it about 45-50 bucks. Not to bad if it saves me spending 900 for a new Ring and Pinion.