Dealer used wrong diff fluid - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

JUSTIFIED · 01-18-2016, 05:27 PM

Just had my diff. fluid replaced today. Manual calls for GM p/n 88900401 (75w-90 Limited Slip) and the dealer put 88862625 (Dexron LS Gear 75W-90.. this is whats used in the ZL1 diff.).

I've called the dealer and am awaiting a return call. I believe the 88900401 is full synthetic whereas the other is not. Could any harm result from temporarily running with non synthetic fluid (street use only)?

Thanks in advance for your input.

Zslash28 · 01-18-2016, 05:56 PM

Likely no worry as long as your only driving it back to the dealer to be changed, and I would expect them to put correct fluid in, let you drive it around and then swap the fluid again.

URBAN LEGEND · 01-18-2016, 06:34 PM

How dare they put lowly ZL1 diff fluid in a Z/28.

69L48Z27 · 01-18-2016, 06:39 PM

Dexron LS is what I've used in Eaton posi units before, clutch type. Not sure that it will hurt anyhting. These rears are Torsen not clutch from what I've read.

X25 · 01-18-2016, 07:11 PM

Since you have helical type differential, you shouldn't need to use a fluid with limited slip additives, which are meant to help out clutch type limited slip differentials, anyway. Are you sure LS type fluid is what is recommended for these cars?

Generally speaking, LS type fluid does not hurt a helical type diff, but it might inhibit the locking performance, depending on its design. Perhaps the unit that GM used doesn't mind the slippery fluid

JUSTIFIED · 01-18-2016, 07:43 PM

Quote:

Originally Posted by URBAN LEGEND

How dare they put lowly ZL1 diff fluid in a Z/28.

LOL

JUSTIFIED · 01-18-2016, 08:10 PM

Okay, talked w/ the dealer. The difference between the 2 fluids is that the fluid they used has a friction modifier and the p/n in the manual refers to a fluid that doesn't have the friction modifier.

I've attached a bulletin where it states that if a customer wishes to reduce the moan coming from the rear end during tight maneuvers then the dealer should add friction modifier. It also states that some customers may want to change back to the other fluid if they feel track performance is diminished.

Like the moan? Do nothing. Don't like the moan? Add the friction modifier. LOL.

JUSTIFIED · 01-18-2016, 08:11 PM

Quote:

Originally Posted by Z28 HLR

No need to get upset here, UL.... His car is still 99% Z/28. Now had they added a sunroof, a big stereo or fog lights, it may be more 12% ZL1. This is not a lost cause yet, there is hope! Swap that fluid out for the correct one and it'll be back to 100% Z/28 again....

JUSTIFIED · 01-18-2016, 08:26 PM

Quote:

Originally Posted by X25

Since you have helical type differential, you shouldn't need to use a fluid with limited slip additives, which are meant to help out clutch type limited slip differentials, anyway. Are you sure LS type fluid is what is recommended for these cars?

Generally speaking, LS type fluid does not hurt a helical type diff, but it might inhibit the locking performance, depending on its design. Perhaps the unit that GM used doesn't mind the slippery fluid

The recommended fluid is referred to as "limited slip". The fluid they used is referred to as "limited slip gear". As mentioned in an earlier post, it contains a friction modifier whereas the other doesn't. You do raise an interesting point... wondering if the friction modifier is the only difference between them... I will call the dealer tomorrow.

vinman · 01-18-2016, 08:41 PM

As long as you have a catch can you're good

URBAN LEGEND · 01-18-2016, 08:50 PM

Quote:

Originally Posted by Z28 HLR

No need to get upset here, UL.... His car is still 99% Z/28. Now had they added a sunroof, a big stereo or fog lights, it may be more 12% ZL1. This is not a lost cause yet, there is hope! Swap that fluid out for the correct one and it'll be back to 100% Z/28 again....

Ok. Ok. I got too excited.

Red Hot ZL1 · 01-19-2016, 10:53 AM

Quote:

Originally Posted by Z28 HLR

No need to get upset here, UL.... His car is still 99% Z/28. Now had they added a sunroof, a big stereo or fog lights, it may be more 12% ZL1. This is not a lost cause yet, there is hope! Swap that fluid out for the correct one and it'll be back to 100% Z/28 again....

Nope, he has to change the badges because he now has a ZL18. He will now also experience the dreaded nonblower heat soak.

Aesthetic Gains · 01-20-2016, 05:09 PM

Quote:

Originally Posted by utaeng96

Okay, talked w/ the dealer. The difference between the 2 fluids is that the fluid they used has a friction modifier and the p/n in the manual refers to a fluid that doesn't have the friction modifier.

I've attached a bulletin where it states that if a customer wishes to reduce the moan coming from the rear end during tight maneuvers then the dealer should add friction modifier. It also states that some customers may want to change back to the other fluid if they feel track performance is diminished.

Like the moan? Do nothing. Don't like the moan? Add the friction modifier. LOL.

Thanks for the info m8

01-18-2016, 05:27 PM	#1
JUSTIFIED Drives: 2015 black Z/28 Join Date: Nov 2015 Location: Texas Posts: 1,081	Dealer used wrong diff fluid Just had my diff. fluid replaced today. Manual calls for GM p/n 88900401 (75w-90 Limited Slip) and the dealer put 88862625 (Dexron LS Gear 75W-90.. this is whats used in the ZL1 diff.). I've called the dealer and am awaiting a return call. I believe the 88900401 is full synthetic whereas the other is not. Could any harm result from temporarily running with non synthetic fluid (street use only)? Thanks in advance for your input.

01-18-2016, 06:34 PM	#3
URBAN LEGEND Drives: 20 X3M CP & 19 ZL1 1LE A10 Join Date: Jun 2013 Location: Brenham, TX Posts: 3,517	How dare they put lowly ZL1 diff fluid in a Z/28. __________________ 🔺22 RS E TRON GT 🔺21 Model S Plaid

01-18-2016, 07:11 PM	#5
X25 Drives: '16 C7 Z51 Join Date: May 2012 Location: Redmond, WA Posts: 3,056	Since you have helical type differential, you shouldn't need to use a fluid with limited slip additives, which are meant to help out clutch type limited slip differentials, anyway. Are you sure LS type fluid is what is recommended for these cars? Generally speaking, LS type fluid does not hurt a helical type diff, but it might inhibit the locking performance, depending on its design. Perhaps the unit that GM used doesn't mind the slippery fluid __________________ '16 Corvette C7 Z51 1LT (Build Thread) '14 AGM 1SS 1LE [COTW 11/17/14] (Build Thread) (SOLD) '13 Mazda MX-5 Club (Build Thread) '17 RAM 1500 Crew Cab 4x4 Night Edition '15 Nissan Rogue S AWD

01-18-2016, 08:41 PM	#10
vinman The BBOMG fill-in husband Drives: 2015 2SS/RS 1LE AKA V1LE Join Date: Aug 2010 Location: Elmira, NY Posts: 4,471 View My Garage	As long as you have a catch can you're good __________________ UPSTATE C5 MEMBER

01-18-2016, 05:56 PM	#2
Zslash28 Jumanji Drives: '14 Z/28 - AGM - No A/C Join Date: Mar 2014 Location: Alaska Posts: 1,693	Likely no worry as long as your only driving it back to the dealer to be changed, and I would expect them to put correct fluid in, let you drive it around and then swap the fluid again.

01-18-2016, 06:39 PM	#4
69L48Z27 Drives: 2015 Z/28; 1969 Camaro SS Join Date: Nov 2015 Location: York, PA Posts: 813	Dexron LS is what I've used in Eaton posi units before, clutch type. Not sure that it will hurt anyhting. These rears are Torsen not clutch from what I've read.