Amsoil 80w-90 for front diff?

[TheFuror]

The Avalanche 4X4 I have says (well, the manual does, anyhows...) that the rear diff needs 75w-90 synthetic but the front requires 80w-90 Gl-5. No mandatory synthetic oil.

I looked around the web and Amsoil makes an 80w-90 synthetic and I had planned to run that. However, some BITOG posters have flat out panned it and/or questioned it. Example:

1). "The regular Amsoil gear oil, not the 2000, is pitiful, that is a statement issued by several Amsoil dealers I have spoken with. They suggest removing it from the market entirely." (Spector, member 74, March 8, 2004).

2). "Who makes the best GL-5 80W-90 synthetic? I've read (on this board?) that Amsoil non-series 2000 in this weight is mediocre. Is this true?" (Par, member 666, August 2, 2004)

I have not been able to locate a synthetic 80w-90 other than Amsoil. I would prefer to run synthetic but am hesitant to switch to 75w-90 when the book calls for 80w-90.

Thoughts?

Thanx

Bob W.

 

[Hammer]

quote:

---

Originally posted by TheFuror:
The Avalanche 4X4 I have says (well, the manual does, anyhows...) that the rear diff needs 75w-90 synthetic but the front requires 80w-90 Gl-5. No mandatory synthetic oil.

I looked around the web and Amsoil makes an 80w-90 synthetic and I had planned to run that. However, some BITOG posters have flat out panned it and/or questioned it. Example:

1). "The regular Amsoil gear oil, not the 2000, is pitiful, that is a statement issued by several Amsoil dealers I have spoken with. They suggest removing it from the market entirely." (Spector, member 74, March 8, 2004).

2). "Who makes the best GL-5 80W-90 synthetic? I've read (on this board?) that Amsoil non-series 2000 in this weight is mediocre. Is this true?" (Par, member 666, August 2, 2004)

I have not been able to locate a synthetic 80w-90 other than Amsoil. I would prefer to run synthetic but am hesitant to switch to 75w-90 when the book calls for 80w-90.

Thoughts?

Thanx

Bob W.

---

The reason many 4X4 front differentials don't specify synthetic is because the front differential is usually hardly used and under much less stress (compared to rear diff) and therefore doesn't need the extra protection or extra cost of synthetics. If the manufactuer can save $10 in the cost of gear oil by not using synthetic in the front, the savings would be a million dollars if he were to sell a 100,000 of these vehicles. IMHO, It is safe to use 75w-90 synthetic in place of 80w-90 petroleum based.

Hammer

 

[Mike_dup1]

I have used Amsoil 75W-90 in place of 80W-90 for many years (first available in 1984) in GM 4x4's. I have it in the front and rear axle on my 2004 GMC Sierra, which is the same as the Avalanche.

This is the one I would use..product code is SVG

[ October 29, 2004, 07:53 PM: Message edited by: Mike ]

 

[Doug]

Mike,

You think in a 1997 Ram 2500 that calls for 80w90 would be fine to run the 75w90? Is the severe gear quite a bit better than the norm Amsoil?

What about the friction mod for the limited slip? I hear that sometimes you don't need it with Amsoil?


Thanks,

Doug

 

[Mike_dup1]

Yes it would be OK in the Ram. The SVG is the best product they have out.

As for "friction mod", I never had to use it myself in any GM truck or car and everyone I have had, has Posi. But if you feel you want it, Amsoil also has it (Slip-Lock) and it won't hurt to add it.

If the Ram is a 4x4 that see's hard use and a truck you plan to keep for a long time, I would use the top of the line SVG. If you don't care and want to save a $ or 2, then the FGR would also be good for normal use.

The first time I used Asmoil gear lubes was back in 1977 when I had a '77 Monte Carlo with Posi. I kept hearing these noise's from my rear axle when I made slow turns. Every-time I complained to the dealer, they added a bottle of Limited Slip Additive. That would only seem to work for a few months and then the noise came back. A gas station I often used is where I got the Asmoil engine oil and he had the gear lube. Got some and had the GM dealer put it in. Had to listen to the service manager and tech berate me for putting it in my new car which they predicted would ruin it, never did. But like I told them (beside FO), they could not do anything (said it was normal and live with it) for the noise and this was worth a try. Since then I have never once heard any noise from my Posi's using the synthetic.

This 2004 GMC SLT has the Series 2000 75W-90 in the front and rear axles. Truck was new in March and had the gear lube in before the end of April. Now had 13,000 miles....

[ October 30, 2004, 08:43 AM: Message edited by: Mike ]

 

[Doug]

cool. Bought some of the SVG. Looking forward to using it. Also got some Amsoil ATF. First time I'll use Amsoil, so maybe I'll be the next Amsoil nut???


Thanks, Doug

BTW, beaut of a truck you got there!

 

[Pablo]

Doug - did you buy it from one of the site sponsors?

Yes the Amsoil SVG 75W-90 will work fine in the front diff.

 

[Doug]

Pab,

No sorry, How do I? I will in the future.

 

[Mike_dup1]

Have synthetic ATF in the truck also for the last month or so. fwiw - Just turned 10,000 miles of the engine oil (5w30 PAO) yesterday, same filter and not used any oil in the 10g. For the heck of it, took a oil sample and dropped in the mail today, see if I can go another 10g on it.

Only lube in the truck that not synthetic is the PS fluid. It says the AC uses synthetic oil per the sticker under the hood.

 

[Pablo]

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