TheDieselPage.com Forums
 
The Diesel Page Forums

2019 - TDP's 23rd Anniversary
What's New | Feature Articles | Product Reviews | Member's Area | Free Forum Registration
Duramax 6600 Diesel Page | Advertiser's Section | Classified Ads | The Diesel Page - Publications


Go Back   TheDieselPage.com Forums > 2001-2019 Chevrolet & GMC 2500HD/3500 Light Trucks > 2500HD/3500 HD Trucks & Drivetrain

2500HD/3500 HD Trucks & Drivetrain Discussion Forum for the 2001 & newer 2500HD/3500 Trucks, Transmissions & Drivetrain

Reply
 
Thread Tools Display Modes
  #1  
Old 02-28-2002, 09:18 AM
TxDoc TxDoc is offline
Enthusiast
 
Join Date: Nov 2000
Location: Texas
Posts: 662
Arrow

"GM introduced the new body style in 1998. At the same time they upgraded
the differential and changed to a synthetic lube. The G80 is specifically
designed to give ultimate performance with this lube, and the lube contains
special additives that help reduce slip stick that occurs between the
clutches. the GM synthetic lube typically runs about 100+ degrees cooler
than mineral base lube, which is better if you do allot of towing or heavy
hauling. I would recommend that you stay with the GM synthetic, not Mobil 1.
If you don't tow or haul you could use the pre 1998 mineral lube without
degrading performance of the differential. this would be a cheaper option
but require more lube changes. "

"Axle tolerances of the 1/2 ton trucks are very tight. The recommended
procedure was to change lube after 500 miles of heavy towing, which would is
considered a break in period. This breaking period generates high heat
conditions in the axle which was found to degrade the synthetic beyond the
point of mineral lube. After the 500 mile lube change, the axle is broke
in and does not generate the high heat. If you use GM synthetic after the
break-in period, it can be considered "lube for life", although some say to
change it at 40,000 - 50,000 mile intervals."

"If you don't tow, don't worry about the oil change as it a waste of money."


"If your truck is pre 1998 or the old style, it comes with mineral lube. IN
that case you need to stay with mineral because the seals are designed to
work with it. If you changed from mineral to synthetic you'll cause your
seals to swell and eventually leak. It's ok to go from synthetic to
mineral because you won't cause swelling. many of your stop leak
chemicals effect seals in this manner, resulting in a short term fix but a
long term problem."
__________________
TxDoc's Photos
Member #5547
Reply With Quote
  #2  
Old 02-28-2002, 10:04 AM
Allison Jettester Allison Jettester is offline
Enthusiast
 
Join Date: Dec 2001
Location: Lexington Park, Md
Posts: 137
Post

TxDoc,

I got this straight off the Eaton Webpage FAQ

http://www.torquecontrol.eaton.com/prod6.htm

"What type of lubricant and limited slip additive should I use with my newly purchased Eaton Limited Slip Differential?

Eaton strongly recommends utilizing an API-GL5 approved Mineral-Based 80W-90 Axle Lubricant and one 4-oz bottle of Limited Slip Additive (GM or Ford)."

I was getting ready to put Mobil 1 in, since it is API-GL5. Other than Eaton's above recommendation and since GM itself is going against this recommendation, why do you not recommend Mobil 1?

If you got your info about their using synthetics from Eaton, are they not also contradicting themselves?

Joe
__________________
02 GMC 2500HD D/A EC LB SLT
FLAME RED! Charcoal Leather Buckets
Pacer 16x8.5 Chrome Split Rims W/285R16 Goodyear MT/R'
Weston Nerf Bars
Fold-A-Cover
Lund Bug Deflector
Air lift Air Springs
Gabriel HiJacker Air Shocks-all 4
JUICED
Elkhorn 11X slide-in
Rinker 212 Captiva
Reply With Quote
  #3  
Old 02-28-2002, 03:34 PM
mark45678
Guest
 
Posts: n/a
Thumbs up

I have been using redline inthe rear end since 600 mile! except I am useing 90/140 weight. no chatter while cornering and locks up tight when it needs to !!! and its about 10 dollars a QT.....
Reply With Quote
  #4  
Old 02-28-2002, 04:00 PM
DmaxMaverick's Avatar
DmaxMaverick DmaxMaverick is offline
Administrator
 
Join Date: Apr 2001
Location: CA
Posts: 12,370
Exclamation

Allison Jettester

Both statements are correct. The Eaton limited slip rear end does require mineral based oil and additive. Synthetic is too slippery and the clutches don't get enough friction to engage and balance torque.

The [Eaton] G80 in the HD's and 3500's is not a limited slip rear end, by traditional terms. It is referred to as the "Gov-Loc" rear end. It does have carbon clutches, but they are engaged by a governor. Using mineral based oil and an additive in this rear end will very likely greatly reduce its useful life. The use of only mineral based oil, without an additive, wouldn't be nearly as bad. The design did not include the use of the additive, which, among other things, contains mostly acid. The acid prevents the oil in traditional limited slip rear ends from glazing to the clutch surfaces, which causes the chatter by preventing lubrication. Synthetic oil will not glaze to the clutches like mineral based oil, and over lubricates the clutches. The G80 in our HD and 3500 trucks do not maintain constant friction like the older limited slip models. It only engages the friction clutches when there is a given amount of differential wheel speed. This has many advantages. Namely the reduction of heat in the rear end, and greatly reduced wear of the friction clutches, as they are not under constant load. See for yourself. Jack up the rear end, both wheels. It will act like an open diff. when one wheel is spinned. Notice no felt friction (or there shouldn't be, anyway).

Why would anyone want to deny his rear end of the best lubricant currently available?

Hope this helps explain it.

Additionally, synthetic oil should be used in the front end of a 4 x 4. Although it is not under the same load, or used as often as the rear end, they are usually neglected by rare service. Mineral based oil will absorb water (from submersion or condensation) and decompose over time (Yes, mineral oils decompose, after all, it is organic. That is why old oil gets that rank smell). Synthetic oils have an indefinite static life. Cheers (Boy! This should stir the pot, not that it is intended to)
__________________
1985 Blazer 6.2
2001 GMC 2500HD D/A
2014 Chevy Cruze Diesel - Fabulous car, no problems at all, but sold Nov. 2016 @ 55K miles.
dmaxmaverick@thedieselpage.com
Reply With Quote
  #5  
Old 02-28-2002, 05:16 PM
kanton1 kanton1 is offline
Enthusiast
 
Join Date: Dec 2001
Location: Eugene, OR
Posts: 107
Post

So...

In simpler terms, does our G80 rear diff require the limited slip additive or not? Changing my fluid this weekend with the $20 quart GM stuff. Thanks in advance

Kyle
Reply With Quote
  #6  
Old 02-28-2002, 06:01 PM
csimo csimo is offline
Enthusiast
 
Join Date: Aug 2001
Location: St. Louis, MO
Posts: 281
Post

No, our axles don't need anything but good synthetic GL-5 rated oil. No additives.

After long investigation the bottom line is that the only GM spec. is for GL-5 synthetic.
Reply With Quote
  #7  
Old 02-28-2002, 08:36 PM
TxDoc TxDoc is offline
Enthusiast
 
Join Date: Nov 2000
Location: Texas
Posts: 662
Post

The post I made was a quote directly from Eaton's reply about what is okay and not okay for use in conjuction with the locking rear end option.

Back in November, I received the following:
"From Mr. Ralph Holmquist of Eaton, the maker of the locking differential:
"The maintenance schedule for the rear axle was developed by American Axle &
Manufacturing and GM truck based on multiple tests. The Eaton locker does
not require additional maintenance nor does it add heat to the lube. The
lube will darken due to the carbon wear on the clutch surfaces, much the
same as a disc brake pad & rotor. This does not damage axle components such
as seals or bearings. However, a new axle can produce excessive
temperatures (plus 350 degrees F) due to the ring & pinion breaking in that
will break the lube additives down. Avoid high loads, trailer towing and
high speed extended driving during the initial break in of the vehicle.
After the break in period axle temps will level at a much lower figure.
Lube changes are a good idea because the additives are replenished and
contaminates such as casting sand are eliminated. The axle is filled at the
factory with a synthetic 75w90 GL5 rating made by Texaco under part # 2276.
The GM service # is 12378261. This is the only lube we have done extensive
testing with to insure locker compatibility. The only negative to using one
of these other lubes is an increased potential for clutch chatter. This
really doesn't hurt anything and can be corrected by changing the lube. I
noticed in the latest GM owners manual the term "or equivalent" when
referring to the lube specification. Look for a GL5 rating on the bottle to
make sure the ring & pinion, seals & bearings are protected. Limited slip
additive is not needed."
The following information outlines the type of
rear axle lubrication utilized in GM Truck axles.
I. Fluid Type
II. The 1500, 2500 and 3500 GMT 800 Trucks utilize SAE 75W-90 Synthetic Axle Lubricant. The GM part number is 12378261 and the specification is 9986115.
__________________
TxDoc's Photos
Member #5547
Reply With Quote
  #8  
Old 02-28-2002, 09:47 PM
Piney Piney is offline
Enthusiast
 
Join Date: Mar 2000
Location: Texas
Posts: 186
Post

More good information! Thanks TxDoc. First time I'd ever heard that about going from mineral to synthetic causing seal problems. Very interesting.
GM needs to pour some magic in their lube bottles if they're going to continue to ask crazy money for it. I'm betting my rear end (no pun intended) that Mobil 1 will work just fine
__________________
02 Chevrolet 2500HD LT Pewter/Tan, 4x4 Crew Cab, Allison and 403 <b>CUBES \'O DIESEL JOY</b>!
Reply With Quote
  #9  
Old 04-18-2002, 03:23 PM
RealBigTruck RealBigTruck is offline
Enthusiast
 
Join Date: Apr 2002
Location: SF Bay Area
Posts: 64
Post

Anyone see a problem with running Redline 80W140 in the G80 rear diff? I've got a case of this stuff.

Gary
__________________
Gary<br /><br />2002 Chevy 3500HD, Duramax, ZF-6, Crew Cab, LongBed<br /><a href=\"http://www.teamSMR.com\" target=\"_blank\">www.teamSMR.com</a>
Reply With Quote
  #10  
Old 04-18-2002, 03:34 PM
Maverick
Guest
 
Posts: n/a
Question

Is the Amsoil synthetic gear lube GL5 rated?
Reply With Quote
  #11  
Old 04-18-2002, 04:28 PM
Edmac Edmac is offline
Enthusiast
 
Join Date: Nov 2000
Location: Pensacola, FL
Posts: 93
Post

Maverick:
Yes at least the 75W140 Amsoil Syn is rated API GL-5, that what I run in mine. I think Eaton recommends this weight for heavy towing.
Ed
__________________
GMC 3500 D/A 4x4, SLT<br />Running Boards, Lucerix Mirrors, gauges,CB,Street Pilot III w/outside antenna, Jordan Brake Controller,U.S.Gear Exhaust Brake,Amsoil Air and Dual Remote Oil Filter,Rhino Bed Liner, Mud Flaps.<p><a href=\"http://www.picturetrail.com/Edmac\" target=\"_blank\">Pictures</a>
Reply With Quote
  #12  
Old 04-18-2002, 04:40 PM
konacat konacat is offline
Enthusiast
 
Join Date: Jan 2002
Location: Torrance CA
Posts: 57
Post

See my previous post.

posted 04-12-2002 11:28 AM
--------------------------------------------------------------------------------
Just hit 1500 miles and have chosen to change engine oil and rear end lube. Get the junk out of it early. Purchased my own gm filter and Rotella dino oil (4gal @ $5.89). Had the local quick oil change location do the service for me. They charged me $39.99 for the rear end lube (Pennzoil 75-90w synthetic) and changed my oil and filter with no additional charge. They even primed the oil filter! Although I am new to diesels, I do not believe that any new noises have occurred.

Yes it is GL-5. Cut and past link below for more info.

http://www.pennzoil.com/TechData/pds...lusSuperEW.pdf

[ 04-18-2002: Message edited by: konacat ]

[ 04-18-2002: Message edited by: konacat ]</p>
__________________
2001 2500HD GMC Duramax/Allison Summit White CC/LB<br />Rhino, Reese 5th wheel hitch<br />2002 Cougar 279EFS<br />1973 CR250M Elsinore
Reply With Quote
  #13  
Old 04-18-2002, 05:50 PM
Tommy turbo Tommy turbo is offline
Enthusiast
 
Join Date: Jan 2001
Location: Fort Worth
Posts: 62
Post

I changed my diff at 500 miles. filled with Castrol 75/90 gl-5 full synthetic. have 18000 miles now no problems.
__________________
2001 2500HD D-Max/Allison C.C. 4x4 L.T. X.M. radio, turn over ball,Prodigy brake controller Westin side bars,285/75/16 BFG A/T, more.
Reply With Quote
  #14  
Old 04-20-2002, 03:20 PM
gdblake gdblake is offline
Enthusiast
 
Join Date: Dec 2000
Location: Runaway Bay, TX, USA
Posts: 37
Post

DMAXMAVERICK (AND /OR OTHERS)--I just purchased Mobil-1 75W-90--it might have a modifier added. Will this be OK for the G80 locker or should I return it? The product sheet states it exceeds requirements for ALL car and truck rear axles, and reduces chatter in limited slips. It states it is suitable for all applications requiring API service GL-5. Please respond. Thank you.

[ 04-20-2002: Message edited by: gdblake ]</p>
__________________
2002 Crew Cab, LS, SB, 2500HD Duramax/Allison, 3.73 LS, Trailering pkg, loaded. White/tan, Buckets
Reply With Quote
  #15  
Old 04-21-2002, 12:09 AM
DmaxMaverick's Avatar
DmaxMaverick DmaxMaverick is offline
Administrator
 
Join Date: Apr 2001
Location: CA
Posts: 12,370
Post

gdblake

Mobil 1 is a high quality lube and should work well with no worries. This, of course, is my opinion. I have not conducted any testing of Mobil 1 gear lube. The additives refered to with most synthetics is not the same as is needed to add to dino oil in a limited slip application.
Reply With Quote
  #16  
Old 04-21-2002, 07:04 AM
gdblake gdblake is offline
Enthusiast
 
Join Date: Dec 2000
Location: Runaway Bay, TX, USA
Posts: 37
Post

Thanks so much, DmaxMaverick--I've really been hangin', hoping for an answer. Anxious to change the diff. Appreciate your response. Had a call into Mobil, but they were closed for the weekend. Best regards!
__________________
2002 Crew Cab, LS, SB, 2500HD Duramax/Allison, 3.73 LS, Trailering pkg, loaded. White/tan, Buckets
Reply With Quote
  #17  
Old 04-21-2002, 07:44 AM
Allison Jettester Allison Jettester is offline
Enthusiast
 
Join Date: Dec 2001
Location: Lexington Park, Md
Posts: 137
Lightbulb

DmaxMaverick,

I've been in Rota, Spain for the past few weeks and didn't see your post answering my post above. I had the mind set that the whole question and answer page on the Eaton website I quoted referred to the G80 Locker. They changed the subject to limited-slip and I didn't catch it (I should have since that is the kind of thing I always look for when reviewing government specs!).
Thanks for straightening me out. That's one thing good about this forum--if you are in error, someone with sharp eyes will catch it.

Anyway, you are correct (as far as I know) that any GL-5 rated synthetic gear oil should be ok in the G80 Eaton's "Gov-Loc" LOCKER. Now that I have bought both Redline (with additive) and Mobil 1 I am going to have to make a decision on which to use.

Also, I did jack up the rear and there was a LOT of friction in the rear when I turned one wheel. I could hear a lot of noise coming from it. I do believe the opposing wheel did turn in the opposite direction like an open diff, but am going to do this again to be sure.

Thanks again,
Joe
__________________
02 GMC 2500HD D/A EC LB SLT
FLAME RED! Charcoal Leather Buckets
Pacer 16x8.5 Chrome Split Rims W/285R16 Goodyear MT/R'
Weston Nerf Bars
Fold-A-Cover
Lund Bug Deflector
Air lift Air Springs
Gabriel HiJacker Air Shocks-all 4
JUICED
Elkhorn 11X slide-in
Rinker 212 Captiva
Reply With Quote
  #18  
Old 01-07-2003, 10:40 PM
DonG DonG is offline
Enthusiast
 
Join Date: Jul 2000
Location: Washington
Posts: 145
Post

TTT
__________________
2003 GMC 3500 SLE, D/A, EC, LB, 2WD, White/Pewter, DeeZee boards, 5th wheel
Reply With Quote
  #19  
Old 01-07-2003, 11:07 PM
wangotango wangotango is offline
Enthusiast
 
Join Date: May 2001
Location: port orchard,wa.
Posts: 220
Post

Am using Almasol 607 from Lube Engineers Inc in a Mag-Hytec rear-end cover.

Towin' like a mutha. No heat/wheel drive issues.

w/t
__________________
2001 black truck, powerful engine,<br />pneumatic tires (4), <br />2-way glass, fully-upholstered inside seating, 12volt dc lighting, one-man steering wheel,interior heating, wipers, aftermarket 8-track...more.
Reply With Quote
  #20  
Old 04-02-2004, 09:06 PM
wxmn6 wxmn6 is offline
Enthusiast
 
Join Date: Sep 2002
Location: Claverack, NY
Posts: 100
Post

Two different fluid to choose from: 75w-90 & 75w-140. Can someone please explain the difference, what each number represent? I'm not too familar with how the fluids are rated. Thanks.
__________________
2002 Chevy Silverado 2500HD<br />Ext. Cab SB 4x4 LS<br />6.0L/HD Auto.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 11:48 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Copyright 1996-2019 by TheDieselPage.com - All Rights Reserved