Hi Guys. I just rebuilt my GU4/G80 read differential on my 2011 Tahoe. 1st couple of days all was fine, super quiet, no rattling, clunking, grinding, all was perfect. Had to run some errands last night and when I went to turn into a driveway there was like a loud pop/clunk came from the rear area. When I went to back out and turned sharp to back out of the space it did it again. Then I had to take a narrow hard curve path to drive around the building to leave and the whole time I have the wheels turned it did it a couple more times. When I got back out on to the road and got straightened up, all drove quiet and great again. It does fine in soft curves, going straight, or backing straight, but if I have a hard curve or have to turn sharp like to get in a parking spot, or to turn in a driveway, loud pops and clunks. What could it be? I really need help in a big way with this, PLEASE!
Rebuilt Differential Help
- Thread starter walterL
- Start date
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Add a bottle of limited slip to it
Did you break it in ??? Needs to be driven slowly
in a wide figure 8 pattern several times. Then let it cool.
Then take it on a 15 drive and then let it cool.
Then change the gear oil in it (add limited slip additive if your
synthetic gear lube doesn't show it has it)
Did you break it in ??? Needs to be driven slowly
in a wide figure 8 pattern several times. Then let it cool.
Then take it on a 15 drive and then let it cool.
Then change the gear oil in it (add limited slip additive if your
synthetic gear lube doesn't show it has it)
This was my 1st diff. to rebuild. I have only driven slow(45mph) with it, but did not do fig. 8's. I did use Valvoline synthetic oil for limited slip. Thanks for the help and I will try the figure 8'sand see what happens. Since I did use the limited slip oil, should I still change it again? Again, thanks for the help, you don't know just how much I appreciate it.
It almost sounds like too much preload to me. It's been a LONG time since I had one apart, but there are specific procedures to follow for preload, tooth engagement, etc. I'm not a professional on rear ends, but my guess is the limited slip portion is too tight and doesn't want to float in a neutral state like it should.
If you have an area that is slippery (snow, wet grass) try doing the same maneuvers and see how it reacts. It will probably be quiet because the tire can slip as needed without being locked to pavement.
If you have an area that is slippery (snow, wet grass) try doing the same maneuvers and see how it reacts. It will probably be quiet because the tire can slip as needed without being locked to pavement.
I had a preload between 20-25 in/lbs. I will give this a shot as well. I have to get this going right so all the advice I can get is welcome. Thank you.
Yes. Change it after the break in procedure. Some diffs like having the extra
limited slip additive in addition to being a GL-5 Spec.. Make sure your valvoline
is a GL-5. I have both on the shelf. Don't assume because it's synthetic that it's
GL5 and has enough limited slip additive for your particular set up
Assuming you have the oem g80 diff. I can only tell you what I experienced with mine and what I've read. but it makes sense to me.
first the g80 in our truck with the weights and stuff is not in any way a limited slip. is a cluch based locker. it is not meant to slip when locked. it seems to kill clutches very quickly if it doesn't lock.
when I got my truck I did the fluids just because I doubt they had ever been done. had no rear end issues at the time. so I picked up fluid at the local auto parts store, I don't even remember which, probably Valvoline since that's what most carry that's good. it listed the limited slip on the bottle. didn't think anything about it.
few days later my wife calls says she was parking and the rear end felt like it was locking up like the race cars we used to be around with a spool. she was around at the track back with me and friends forever ago. so she is familiar with us trying to push cars to the lanes with a a spool, (locked diff) I told her I'd check it out when she got home. so I took it around, and in a parking lot doing tight turns the diff would chatter like it was trying to lock. it shouldn't be doing that unless one tire is spinning faster be a decent amount.
so after some Googling, it seems like it doesn't happen to everyone but some get chatter when putting limited slip fluid in it since it's a locker I guess. I was skeptical but went back to the store and looked thru all the fluid. not a single one lists without limited slip. so I gave up, ran up to the dealer parts department just before they closed. looked up what they have for my vin. it's pricey like everything there. you'll have like 50$ in fluid. but came home, dumped it and added the new stuff. went out to the same parking lot, after a few figure 8s it was smooth. hasn't made a sound since and seems to be correct.
I learned to use the gm stuff from the corvette world. they have a true limited slip and they have like 7 tsb's about diff chatter, cluncks and worn clutches. there's been 7 revisions to the fluid and it has its own part number and the correct amount and type of additive already mixed it. there's 50 page threads on it on their boards, so when I did that car I went straight to gm and got fluid. wasn't going to deal with that hassle haha.
just my experience. your experience, especially with a fresh rebuild might be different. I believe most people have no issues with auto parts store fluid. I wouldn't have never known if I didn't spend a night digging up old threads.
first the g80 in our truck with the weights and stuff is not in any way a limited slip. is a cluch based locker. it is not meant to slip when locked. it seems to kill clutches very quickly if it doesn't lock.
when I got my truck I did the fluids just because I doubt they had ever been done. had no rear end issues at the time. so I picked up fluid at the local auto parts store, I don't even remember which, probably Valvoline since that's what most carry that's good. it listed the limited slip on the bottle. didn't think anything about it.
few days later my wife calls says she was parking and the rear end felt like it was locking up like the race cars we used to be around with a spool. she was around at the track back with me and friends forever ago. so she is familiar with us trying to push cars to the lanes with a a spool, (locked diff) I told her I'd check it out when she got home. so I took it around, and in a parking lot doing tight turns the diff would chatter like it was trying to lock. it shouldn't be doing that unless one tire is spinning faster be a decent amount.
so after some Googling, it seems like it doesn't happen to everyone but some get chatter when putting limited slip fluid in it since it's a locker I guess. I was skeptical but went back to the store and looked thru all the fluid. not a single one lists without limited slip. so I gave up, ran up to the dealer parts department just before they closed. looked up what they have for my vin. it's pricey like everything there. you'll have like 50$ in fluid. but came home, dumped it and added the new stuff. went out to the same parking lot, after a few figure 8s it was smooth. hasn't made a sound since and seems to be correct.
I learned to use the gm stuff from the corvette world. they have a true limited slip and they have like 7 tsb's about diff chatter, cluncks and worn clutches. there's been 7 revisions to the fluid and it has its own part number and the correct amount and type of additive already mixed it. there's 50 page threads on it on their boards, so when I did that car I went straight to gm and got fluid. wasn't going to deal with that hassle haha.
just my experience. your experience, especially with a fresh rebuild might be different. I believe most people have no issues with auto parts store fluid. I wouldn't have never known if I didn't spend a night digging up old threads.
donjetman
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@walterL
My Denali w/G80 and all my other vehicles w/posi differentials (Corvette C5, 51 Chevy w/Corvette diff, FJ) get either Amsoil or Redline synthetic gear oil and have never had any issue(s).
Your results may vary.
My Denali w/G80 and all my other vehicles w/posi differentials (Corvette C5, 51 Chevy w/Corvette diff, FJ) get either Amsoil or Redline synthetic gear oil and have never had any issue(s).
Your results may vary.
Just Fishing
Can't fix stupid
My vette with the oem limited slip needs the additive even though I use fluid that says it already contains it.
My S10 (ZR2) is probably closer to what the Tahoe's have.
I was always told that even though it's a G80, it's not a limited slip.
more of a locker that has clutches that just cushion it.
I had it lock on me one time doing a U turn in phoenix az, it was like 115 degrees outside.
it locked and I couldn't turn.
I went up onto the curb.
That was back when that s10 only had like 40k on it.
I was always told to never run the limited slip additive in the rear end of that S10, and to do my best to buy gear oil that doesn't specify it already has it.
I followed that and never had any issues.
When I gave the S10 away the rear g80 still worked, only thing done was to replace the bearings in it.
I didn't touch the internals of the G80.
just axle bearings, and new pinion bearings w/new seals.
When I gave it away I was at like 250-270k.
My nephew said it was amazing offroad, so I assume the G80 was still working for him.
My S10 (ZR2) is probably closer to what the Tahoe's have.
I was always told that even though it's a G80, it's not a limited slip.
more of a locker that has clutches that just cushion it.
I had it lock on me one time doing a U turn in phoenix az, it was like 115 degrees outside.
it locked and I couldn't turn.
I went up onto the curb.
That was back when that s10 only had like 40k on it.
I was always told to never run the limited slip additive in the rear end of that S10, and to do my best to buy gear oil that doesn't specify it already has it.
I followed that and never had any issues.
When I gave the S10 away the rear g80 still worked, only thing done was to replace the bearings in it.
I didn't touch the internals of the G80.
just axle bearings, and new pinion bearings w/new seals.
When I gave it away I was at like 250-270k.
My nephew said it was amazing offroad, so I assume the G80 was still working for him.
that's kinda been my experience. the fluid you can easily get all says limit slip additive, but it's not enough for a real one, but to much for these weird lockers.
so you gotta still add some, or try and find some without it. which I wasn't about to do. maybe straight non synthetic 80-90 if you could find it. but anything that said 75/90 has something about limited slip on the bottle.
which is why I give up, I'll just let gm do it and use what they call out. it's easier.
I do believe there's higher quality fluid than the oem stuff, like say an amsoil. but it's about having to guess if you got the right amount of friction modifiers for wear vs slip
so you gotta still add some, or try and find some without it. which I wasn't about to do. maybe straight non synthetic 80-90 if you could find it. but anything that said 75/90 has something about limited slip on the bottle.
which is why I give up, I'll just let gm do it and use what they call out. it's easier.
I do believe there's higher quality fluid than the oem stuff, like say an amsoil. but it's about having to guess if you got the right amount of friction modifiers for wear vs slip
This might sound dumb...not in 4hi on dry pavement?
The 2 diffs are the 100% same?
swathdiver
Full Access Member
What exactly did you replace? What was the rotational torque and the preload on the ring and pinion?
If this were mine, the rear cover would have been off already.
First off I want to thank all for the advice. This past weekend I tore the whole thing back down and put it all back together by the book. I am going to enclose a pic of the gear oil I used in this post. I drove it easy to work today because we have a massive parking area I can do the fig. 8's. On the way here, it did make the clunking noise when I had to turn left, and a lighter noise when I had to turn right. I did not see any visible problems when I tore it back down, everything was pristine in the housing. I will definitely let you guys know the out come after doing the fig. 8's. Forgot to say that when going straight or through soft curves, it is quieter than a mouse. Hopefully its the sticky clutches.
I went back stock. I replaced all the bearings, spider gears, and side gears
Mine is just 2wd
Mornin all. Just wanted to come in for an update this morning. After work yesterday I went for a figure 8 test drive, and I admit that if I didn't see it myself, I might not have believed it, but doing the figure 8's has worked. I still have a very light pop, but all in all it is much better handling. I'm thinking I need to do a few more fig. 8's but I would say after yesterday that it is 98% better like night and day. Thank you all for the help but especially @Foggy who told me about the fig. 8's. Thanks everyone again, can't say it enough!
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