03 chevy S-10 ZR2, what fluid?

[OdinsRage]

A guy at work wants me to change this for him... his transfer case, and front and rear diffs. I need to know what weight fluid, and GL-4, or GL-5

The rear is limited slip-- will i need additive? If its a clutch system, yes, but if its gear, i dont think i will, but I dont know what system it is.

Hopefully I can just fill everything with M1 75w-90 and call it a day?

 

[04SpecV]

Some of the transfercases use ATF. Might want to double check on that one.
The M1 75W90 should be fine for the diffs. I think most GM trucks have what is called a gov lock. I don't think they require limited slip additive at all.

 

[BlazerLT]

75w90 for synthetic
80w90 conventional

GL-5 requires no limited slip additive.

 

[vicmackey]

If you are on here asking these questions should you really be doing this project?

You should really check the manual.

 

[OdinsRage]

quote:

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Originally posted by BlazerLT:
75w90 for synthetic
80w90 conventional

GL-5 requires no limited slip additive.

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i put GL-5 mobil 1 75w90 in my 96 vette without additive and it made awfule groaning noises on turns, the GM additive cured it.

 

[Mike_dup1]

You have to determine if the S10 has a locker or a Limited slip.

You can use 75W-90 in both the front and rear axle, it will not make a difference what so ever from a 80W-90.

GM Cars has Limited Slip Differentials and need an additive

GM Trucks have locking differentials and don't need the additive.

Don't confuse the 2 as they are completely different G80's. Use of the additive in the truck LRD will have a negative effect.

LOCKING DIFFERENTIAL LUBRICANT (SERVICE INFORMATION) #91-4-109
SUBJECT: LOCKING DIFFERENTIAL (G80) LUBRICANT - (SERVICE INFORMATION)
VEHICLES AFFECTED: ALL LIGHT TRUCKS EQUIPPED WITH G80 REAR AXLE ALL YEARS
Some light duty trucks equipped with locking rear axles (G80) may exhibit rear axle chatter, especially when turning a corner from a stop.
This condition of alternate engagement and disengagement of clutches in differential assembly is usually caused by contaminated axle lubricant.
To correct this condition, drain and refill the rear axle with SAE 80W-90 GL5 (P/N 10950849). The use of any additive in locking rear axles (G80) is not recommended. Rear axle additives are designed for use in limited slip differentials which are normally installed in cars. All light duty trucks equipped with RPO G80 make use of a locking differential and the use of additives will delay the engagement of the locking mechanism and may decrease axle life.
VEHICLES/COMPONENTS INVOLVED:

 

[OdinsRage]

how about transfer case? 75w90 as well?

 

[Mike_dup1]

No gear lube in transfer case.

If its a 4sp trans, case uses ATF

if A/T, transfer case uses special GM fluid, no one else has it, GM is the only source for it.

I would to do more checking but I think it would be, GM AutoTrac II.

Maybe you should consult his owners manual. Better yet, let him do it and then he can't blame you if there is a screw up.

 

[OdinsRage]

finally read the manual, we are going to use 75w90 M1 for front and rear diffs, transfer case takes ATF dexronIII, we are going to use mobil 1 ATF for that. And Also M1 ATF for the trans with a pan drop.