best rear end oil

**fbodyNATION** · 03-24-2011, 08:12 AM

i will be doing a full spring time fluid change(oil,trans,coolant)etc.but i dont know which gear oil would be best for my rear end,what gear oil are you guys using? what do you recommend? i have a 2000 T/A thanks

**TLS_Addict** · 03-24-2011, 01:01 PM

I am going to try the Mobil 1 75-90.

Check this out. http://www.ls1.com/forums/showthread.php?t=152383

**KMdef9** · 03-24-2011, 03:36 PM

I have Royal Purple in mine. Mobil 1 would be fine with me as well.

**pajeff02** · 03-24-2011, 04:18 PM

Good old Valvoline 80W-90 right now. May switch over to Amsoil this summer.

**JayTA98** · 03-24-2011, 09:02 PM

valvoline here as well.

**Sarge** · 03-27-2011, 01:43 PM

This is recent (GL-5) and well done by a respected lab utilizing accepted certifiable repeatable testing. Make/draw your own conclusions.....
Gear Lube Test

**02transamce** · 03-27-2011, 02:00 PM

Valvoline 80w90
Posted via Mobile Device

**pajeff02** · 03-27-2011, 06:09 PM

Great info. Looks like the Valvoline is getting drained out next time the car goes in the air.

**iam_dale** · 03-28-2011, 08:51 AM

DAMNIT!! All I've seen on base here for gear lube is RP...and it's $20/liter......

**TLS_Addict** · 03-28-2011, 11:44 AM

Been 200 miles on the gear change and the gears are doing great with the Mobil 1 I used. No chatter or anything.

**FasstChevys** · 03-28-2011, 12:14 PM

Originally Posted by TLS_Addict

Been 200 miles on the gear change and the gears are doing great with the Mobil 1 I used. No chatter or anything.

Well - the only way to truly know what's going on in there is to take a sample, and send it off for testing.

**TLS_Addict** · 03-28-2011, 01:39 PM

Very true, as its been 200 miless I am going to leave it be for a while.

I might do that though so that the it can go on record here for others on the site.

**Cutlass** · 03-28-2011, 06:45 PM

Originally Posted by Sarge

Make/draw your own conclusions.....

A test sponsored by Amsoil where Amsoil is the clear winner...any reason to be suspicious?

**blackSS01** · 03-28-2011, 07:28 PM

I go with Amsoil.

**bberretta** · 03-29-2011, 05:23 AM

It also depends on the posi you have- if you have a clutch pack posi then I was recommended by MidWest Chassis to stay away from synthetic gear oils and stick with conventional 80w90 and use the appropriate posi additive. I've had my 9" running for 6k miles with that and it's the quietest thing on my car!

**99WickedSS** · 03-29-2011, 06:10 AM

Originally Posted by bberretta

It also depends on the posi you have- if you have a clutch pack posi then I was recommended by MidWest Chassis to stay away from synthetic gear oils and stick with conventional 80w90 and use the appropriate posi additive. I've had my 9" running for 6k miles with that and it's the quietest thing on my car!

You beat me to it...I have a Moser 12 bolt Eaton posi and Moser specifically states all of their testing is conducted using conventional 80w90 and GM friction additive 1052358. This combination has proved reliable and keeps it quiet.

**pajeff02** · 03-29-2011, 08:31 AM

Originally Posted by 99WickedSS

You beat me to it...I have a Moser 12 bolt Eaton posi and Moser specifically states all of their testing is conducted using conventional 80w90 and GM friction additive 1052358. This combination has proved reliable and keeps it quiet.

CompSyn actually posted up some good info in response to why Moser recommends conventional gear oil. Essentially, it is based on some very outdated testing. I will be switching our Moser over to Amsoil this summer.

**99WickedSS** · 03-29-2011, 04:32 PM

Originally Posted by pajeff02

CompSyn actually posted up some good info in response to why Moser recommends conventional gear oil. Essentially, it is based on some very outdated testing. I will be switching our Moser over to Amsoil this summer.

Let me know how it works out, perhaps next summer I'll change over to synthetic.

**Wesman** · 03-29-2011, 05:57 PM

Originally Posted by Cutlass

A test sponsored by Amsoil where Amsoil is the clear winner...any reason to be suspicious?

I was thinking the same thing.

The Amsoil did not only win, but it beat the other oils by a huge margin. Just seemsa little too coincidental.

I'm going to be running Redline Shockproof 75W-250 in my rear as soon as the gears are broken in. The stuff is amazing, its extremely viscous and clings to bearing and gears better than anything I've ever seen, yet it only has the frictional loss of a 75W-90. With all the failures of rears in our cars due to shock loading which results in broken gear teeth and damaged bearings, this product should be excellent. My friend has been running it in his '05 GTO and he's been very satisfied with the performance.

**02transamce** · 03-29-2011, 06:52 PM

Originally Posted by pajeff02

CompSyn actually posted up some good info in response to why Moser recommends conventional gear oil. Essentially, it is based on some very outdated testing. I will be switching our Moser over to Amsoil this summer.

keep us updated,i would like to run a good syn gear oil in my moser 12 bolt but as you know they strictly said 80w90 conventional,btw mine has eaton clutch disc style posi.