Recent Topics
Getting the cars rust proofed on the 27th
by redhat
13 minutes 6 seconds ago
11 Mercedes ML350 Bluetec 3.0L M1 ESP 5W-40
by BigDz
35 minutes 23 seconds ago
Just some questions (Pennzoil ultra 0w-20) & ATF
by TylerHTC
42 minutes 1 second ago
Smell of coolant after water pump leak.
by RogerBacon
Today at 06:47 AM
The audacity of auto part store prices
by Nayov
Today at 05:54 AM
F1 - 2014 Singapore Grand Prix
by gofast182
Today at 05:46 AM
Piston soak, alternatives to MMO?
by 19jacobob93
Today at 05:44 AM
Toyota Power Steering filter
by 01_celica_gt
Today at 04:28 AM
UOA Mailing Issues
by The Critic
Today at 02:56 AM
just curious about recycle oil and where it goes
by coach477
Today at 02:51 AM
9/17-9/30 O'Reilly Super Saver Ad
by tenderloin
Yesterday at 11:57 PM
'13 WRX: Mobil 1 ESP 5w30, 6,590 mi
by WRX12tt
Yesterday at 11:54 PM
Newest Members
waynesworld, Arcticfox, informme, Sherlock, Pokermatters
51330 Registered Users
Who's Online
59 registered (ARCOgraphite, apwillard1986, Astro14, ac_tc, Artem, Bamaro, 8 invisible), 1382 Guests and 233 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
51330 Members
64 Forums
219408 Topics
3462351 Posts

Max Online: 2862 @ 07/07/14 03:10 PM
Donate to BITOG

Topic Options
#2299890 - 06/27/11 09:58 PM How hot does the gear oil get in a GM rear end?
Loobed Offline


Registered: 07/20/07
Posts: 3742
Loc: Northern California, USA


Does anyone know what the upper operating temperature of the gear oil in a GM truck rear end. It is an 8.6" 10 bolt, but I would guess all sizes are close to the same temps.

thanks
_________________________
Engine: 2001 GM 5.3L LM7
Current Fill: Valvoline Synpower 5w-30 w/Pure-One PL25288 filter

I.M.N Oil Enthusiast

Top
#2299922 - 06/27/11 10:28 PM Re: How hot does the gear oil get in a GM rear end? [Re: Loobed]
dparm Offline


Registered: 04/19/10
Posts: 12503
Loc: Chicago, IL
For what kind of duty? Daily driving? Off-roading? Towing? Racing?
_________________________
2011.5 BMW M3 saloon ZCP
der stärkste buchstabe der welt
Castrol Edge Professional TWS 10w60 + Mahle OX 254D3

Top
#2299944 - 06/27/11 10:51 PM Re: How hot does the gear oil get in a GM rear end? [Re: dparm]
MetalSlug Offline


Registered: 07/24/10
Posts: 2134
Loc: vicksburg ms
Originally Posted By: dparm
For what kind of duty? Daily driving? Off-roading? Towing? Racing?


why you would include " racing " leave that out lol. its a truck.

what year is the truck ?
_________________________
05 Expedition 5.4L 3v Super Mobil 5w20 FL820s

Top
#2299951 - 06/27/11 11:01 PM Re: How hot does the gear oil get in a GM rear end? [Re: Loobed]
Gene K Offline


Registered: 01/25/03
Posts: 3161
Loc: Decatur AL USA
Originally Posted By: Loobed


Does anyone know what the upper operating temperature of the gear oil in a GM truck rear end. It is an 8.6" 10 bolt, but I would guess all sizes are close to the same temps.

thanks



Ambient temp and load would play into it. It will run much cooler in town empty at 60F ambient than pulling a 20 mile long 3% grade in 120F heat grossing 14,000 lb with a trailer. Condition 1 might be 120F and condition 2 might be 280F.


Edited by Gene K (06/27/11 11:04 PM)
_________________________
Gene






Top
#2299970 - 06/27/11 11:29 PM Re: How hot does the gear oil get in a GM rear end? [Re: Loobed]
Loobed Offline


Registered: 07/20/07
Posts: 3742
Loc: Northern California, USA

It is a 2001 GMC Sierra 1500 4WD (1/2 ton).

I am driving mostly around town and on the highway with an empty bed. I might drive 2 times a year to the mountains (150 +miles one way) fully loaded, with a little of road dirt trail driving in 4WD. I have not towed in 8 years, and I don't expect to tow in the near future. No racing.
_________________________
Engine: 2001 GM 5.3L LM7
Current Fill: Valvoline Synpower 5w-30 w/Pure-One PL25288 filter

I.M.N Oil Enthusiast

Top
#2299987 - 06/28/11 12:39 AM Re: How hot does the gear oil get in a GM rear end? [Re: Loobed]
ARB1977 Offline


Registered: 06/12/05
Posts: 4477
Loc: North Texas
Loads, outside temps and how much oil is in the diff... so really its hard to say. Run synthetic or dino and proper viscosity you'll be fine.
_________________________
2002 Tacoma 3.4L 159K (as of 04-05-14)
M1 HM 5W30 / Fram Synthetic

2008 CRV 2.4L 105K (as of 03-22-14)
PP 0W20 / Honda A02

Top
#2299990 - 06/28/11 12:43 AM Re: How hot does the gear oil get in a GM rear end? [Re: Loobed]
Gene K Offline


Registered: 01/25/03
Posts: 3161
Loc: Decatur AL USA
Originally Posted By: Loobed

It is a 2001 GMC Sierra 1500 4WD (1/2 ton).

I am driving mostly around town and on the highway with an empty bed. I might drive 2 times a year to the mountains (150 +miles one way) fully loaded, with a little of road dirt trail driving in 4WD. I have not towed in 8 years, and I don't expect to tow in the near future. No racing.



Maybe 200F.
_________________________
Gene






Top
#2300000 - 06/28/11 01:15 AM Re: How hot does the gear oil get in a GM rear end? [Re: Loobed]
Bluestream Offline


Registered: 09/13/03
Posts: 3907
Loc: Waterloo, ON
Next time put your hand on your diff after driving around. You will have your answer...
_________________________
2000 Cavalier 2.2 A4
2000 VW Beetle 1.8T M5
2000 Ford Explorer 4.0 4X4
1991 BMW 735iL
"A fool and his money are soon parted" - Thomas Tusser

Top
#2300007 - 06/28/11 01:33 AM Re: How hot does the gear oil get in a GM rear end? [Re: Bluestream]
tinmanSC Offline


Registered: 09/07/10
Posts: 1916
Loc: Oswego, IL
Originally Posted By: Bluestream
Next time put your hand on your diff after driving around. You will have your answer...

Ouch!
_________________________
Cost of Hobby=2L
(Where L=Cost of Lubricant)
95 Lexus SC300 5-spd@200K, 2000 GS300@120K both VML Full Syn+Purolator PSL20195(soon to be Wix)

Top
#2300631 - 06/28/11 04:10 PM Re: How hot does the gear oil get in a GM rear end? [Re: tinmanSC]
Bluestream Offline


Registered: 09/13/03
Posts: 3907
Loc: Waterloo, ON
Originally Posted By: tinmanSC
Originally Posted By: Bluestream
Next time put your hand on your diff after driving around. You will have your answer...

Ouch!


If its that hot to burn you hand you have real problems. Mine never gets past warm...
_________________________
2000 Cavalier 2.2 A4
2000 VW Beetle 1.8T M5
2000 Ford Explorer 4.0 4X4
1991 BMW 735iL
"A fool and his money are soon parted" - Thomas Tusser

Top
#2301049 - 06/28/11 11:39 PM Re: How hot does the gear oil get in a GM rear end? [Re: Loobed]
mechtech2 Offline


Registered: 09/05/06
Posts: 19479
Loc: Chicago Area
A lightly loaded rear end should be from ambient to maybe 150F or so.

Top
#2301174 - 06/29/11 07:21 AM Re: How hot does the gear oil get in a GM rear end? [Re: Loobed]
Jim Allen Offline


Registered: 08/12/05
Posts: 4477
Loc: NW Ohio
The 8.5 (an older generation of your 8.6) in my old diesel Blazer ran around 180-200F in 80-90F ambient, lightly loaded, with 4.10 gears and a Detroit Locker installed.

Smaller ring gears in axles with small oil capacities generate some pretty high temps with heavy loads. Also, lower gears run hotter than high gears. The rules of thumb I was given (and have largely observed) is around a 10-15 degree spread between 3.08 gears and 4.10s. This has to do with the taller gears having more tooth contact, spreading the load over a larger area, and they run a little cooler.

The faster you go the hotter the diff also.
_________________________
Jim Allen
Keepin' the Good Old Days of Four Wheeling Alive

Top
#2301493 - 06/29/11 12:58 PM Re: How hot does the gear oil get in a GM rear end? [Re: Loobed]
mechtech2 Offline


Registered: 09/05/06
Posts: 19479
Loc: Chicago Area
Jim - That's kinda hot for a lightly loaded rear end.
That 4.10 is part of it.

Top
#2301549 - 06/29/11 01:49 PM Re: How hot does the gear oil get in a GM rear end? [Re: mechtech2]
Jim Allen Offline


Registered: 08/12/05
Posts: 4477
Loc: NW Ohio
Hey Mechteh- It's in line with what I have seen elsewhere and on my current trucks. Probably should have mentioned that my numbers are obtained by running at a steady freeway speed for as long as it takes to stabilize the oil temp. Sometimes that takes 15 miles or so. Running around town at 35-50 mph knocks 20-30 degrees off that. Some of that temp is load from windage (and that lifted Blazer was a brick). Some of the extra heat is compensated for by air cooling, I suppose. Anyway, it was what it was and may not apply to anything else, though I've found a lot of correlation bin gear ratios, ring gear size, oil capacity and load.
_________________________
Jim Allen
Keepin' the Good Old Days of Four Wheeling Alive

Top