What would the front diff be and what fluids?

partsman · 02-19-2009, 08:04 PM

So will be picking up the 1996 Sierra 2500 4x4 7.4 litre truck I mentioned in another post, this Saturday, the salesman did not seem to know what fluids they use and said they just use standard fluids, so use what I like.

My problem is that if one has a locking diff as he called it, or a limited slip as the build sheet calls it, I thought they used an oil and also an additive and what would the transfer case use?

I know it is a 4L80E tranny, so the old dextron I have should work.

Any input on this?

leolkfrm · 02-19-2009, 10:35 PM

rear diff standard oil and additive, front standard oil
good luck with the new truck

ukrkoz · 02-21-2009, 07:00 PM

call dealership and check. 99 uses 75w90 oil. should not be that much difference for 3 yrs. yeah, and don't be cheap. save money and put amsoil in. i mean - save money on future repairs.

bahrkodu · 03-31-2009, 05:56 AM

these trucks do just take standard gl-5 gear oil in the front and rear diff i agree with ukrkoz ams oil is one of the better diff fluids . for the rear diff if you tow a trailer with it i would say to use a synthetic 75w140 the transfer case can be a tricky one if you have push button 4 wheel drive it would take a dealer only auto trak fluid but if you 4 wheel drive shifter is on the ground than any dexron 3 atf would do it

partsman · 03-31-2009, 07:07 AM

Yep, mine has the buttons on the dash that you push for 2hi 4lo or 4hi

NonGoggleGuy · 03-31-2009, 11:12 AM

Rear: 75W-90 with limited slip additive (I'd use GM's additive just for peace of mind)
Front: 75W-90
Tranny: Dextron

batty1214 · 03-31-2009, 06:59 PM

If you run a 75w90 in both diffs, you really won't have a problem...... I've been running it in all of the work pickups(45 of them now) and don't forget the additive.

a new guy at work did on one of our trucks...... ahh... job security

02-19-2009, 08:04 PM	#1
partsman Senior Member Join Date: Jul 2008 Location: Poco BC Posts: 97	What would the front diff be and what fluids? So will be picking up the 1996 Sierra 2500 4x4 7.4 litre truck I mentioned in another post, this Saturday, the salesman did not seem to know what fluids they use and said they just use standard fluids, so use what I like. My problem is that if one has a locking diff as he called it, or a limited slip as the build sheet calls it, I thought they used an oil and also an additive and what would the transfer case use? I know it is a 4L80E tranny, so the old dextron I have should work. Any input on this?

02-19-2009, 10:35 PM	#2
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,927	rear diff standard oil and additive, front standard oil good luck with the new truck __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

03-31-2009, 11:12 AM	#6
NonGoggleGuy Senior Member Join Date: Mar 2009 Location: New York State Posts: 267	Rear: 75W-90 with limited slip additive (I'd use GM's additive just for peace of mind) Front: 75W-90 Tranny: Dextron __________________ Bored? Check out Project: Wreck. But only if you're really bored. - The NonGoggleGuy - I'm unbelievable... believe me.

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02-21-2009, 07:00 PM	#3
ukrkoz Senior Member Join Date: Feb 2008 Posts: 173	call dealership and check. 99 uses 75w90 oil. should not be that much difference for 3 yrs. yeah, and don't be cheap. save money and put amsoil in. i mean - save money on future repairs.

03-31-2009, 05:56 AM	#4
bahrkodu Senior Member Join Date: May 2008 Location: stony plain alberta,canada Posts: 91	these trucks do just take standard gl-5 gear oil in the front and rear diff i agree with ukrkoz ams oil is one of the better diff fluids . for the rear diff if you tow a trailer with it i would say to use a synthetic 75w140 the transfer case can be a tricky one if you have push button 4 wheel drive it would take a dealer only auto trak fluid but if you 4 wheel drive shifter is on the ground than any dexron 3 atf would do it

03-31-2009, 07:07 AM	#5
partsman Senior Member Join Date: Jul 2008 Location: Poco BC Posts: 97	Yep, mine has the buttons on the dash that you push for 2hi 4lo or 4hi

03-31-2009, 06:59 PM	#7
batty1214 Senior Member Join Date: Nov 2008 Location: Vernal Utah Posts: 1,276	If you run a 75w90 in both diffs, you really won't have a problem...... I've been running it in all of the work pickups(45 of them now) and don't forget the additive. a new guy at work did on one of our trucks...... ahh... job security