Rear and Front Diff Fluid
- Thread starter lts1ow
- Start date
Question
I just changed my diff fluids. I used Mobil 1 synthetic 75W-90. Now im experience diff chatter. Dealer said to add a 4 oz shot of LS additive. But iv read/heard its not good to add any LS additive to a G80. Would I be ok adding the 4oz shot of LS additive to my diff?
I just changed my diff fluids. I used Mobil 1 synthetic 75W-90. Now im experience diff chatter. Dealer said to add a 4 oz shot of LS additive. But iv read/heard its not good to add any LS additive to a G80. Would I be ok adding the 4oz shot of LS additive to my diff?
No additives in the G80.
You're the first I know of with chatter using M1 75w90. I had that using Amsoil Severe Gear but M1 solved the problem
Sent from my SCH-I535
You're the first I know of with chatter using M1 75w90. I had that using Amsoil Severe Gear but M1 solved the problem
Sent from my SCH-I535
If you live in a warm climate yes but in the cold it would take forever to warm up causing premature gear wear.
Iv read a TSB about not to use a LS additive in a G80. The TSB said if diff chatter presents, drain the gear oil, & refill with a GM brand (88900401) GL-5 75w-90 gear oil. Id hate to pay 20-30$ a bottle for GM brand gear oil. Im gonna call another GM service writer on Monday & hear what he says.
140 in the rear is only for those that tow or haul a lot. Put 75w-90 in both diffs.
Do burn outs, boosted launches and W.O.T several times a day fall into extreme service requirement? I think for most here the 140 should be "recommended" as we tend to be a little more demanding on the rear end, but I do tow quite a bit, or did...
My dealership said the additive wasn't needed for the G-80 but did recommend it for the rear diff on my trailblazer which has a 14 bolt 10.5" rear diff although I'm not sure which limited slip is in it? They also said the using Mobil 1 synthetic trumped the need for the additive. FWIW
:angel:
Do burn outs, boosted launches and W.O.T several times a day fall into extreme service requirement? I think for most here the 140 should be "recommended" as we tend to be a little more demanding on the rear end, but I do tow quite a bit, or did...
I never really thought about it like that. 140 in the rear does sound like a good recommendation, for those that have added power.
Well I talked on the phone with a GM service writer and went in person to talk to him and a mechanic from the dealer. They both told me theyd drain the fluid and replace with GM brand gear oil. They said GM brand gear lube would fix the diff chatter. I didnt want to shell out $ for gear oil ($30 a bottle) that may or may not fix the diff chatter. Plus I just replaced the diff fluid a few days ago. More $ down the drain for a maybe fix.
I have a 3rd party warranty (which should be voided cause I tuned my truck) so I left the truck at dealer. They drained the fluid checked to see if the rear end is ok. Rear end was ok. They added GM brand GL-5 synthetic 75W-90. I picked the truck up and diff chatter was gone. Then this morning as I backed out of the driveway the diff chatter was back and worse/a lot more noticeable.
I took it back to the dealer and the service writer and mechanic both agreed to add some LS additive. Service writer and mechanic said this small amount of added LS additive shouldnt cause problems. No more diff chatter but we shall see if last.
BTW all it cost me was $13 for the 4 oz LS additive. Warranty took care of the rest.
I have a 3rd party warranty (which should be voided cause I tuned my truck) so I left the truck at dealer. They drained the fluid checked to see if the rear end is ok. Rear end was ok. They added GM brand GL-5 synthetic 75W-90. I picked the truck up and diff chatter was gone. Then this morning as I backed out of the driveway the diff chatter was back and worse/a lot more noticeable.
I took it back to the dealer and the service writer and mechanic both agreed to add some LS additive. Service writer and mechanic said this small amount of added LS additive shouldnt cause problems. No more diff chatter but we shall see if last.
BTW all it cost me was $13 for the 4 oz LS additive. Warranty took care of the rest.