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80w90 gear oil okay?

Posted: Fri Oct 02, 2015 7:44 am
by kdiqq
I went to auto zone last night to try and find 90wt gear oil but had no luck. What gear oil I did find was GL-5 80w90.

I'd like to get all this fluid swapped out soon and not pay for Redline MT90. Since I live in Houston, I don't see extreme cold temperatures. What's the consensus? I tried searching and it appears that folks run all 90wt. Where do yall find this stuff?!

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Re: 80w90 gear oil okay?

Posted: Fri Oct 02, 2015 8:28 am
by pinzinator
Use the Redline if this is intended for the transmission, it is worth the extra cost. I have had this in my Pinz for many years.

Re: 80w90 gear oil okay?

Posted: Fri Oct 02, 2015 9:19 am
by kdiqq
I've used synthetics for a long time in everything hot rod and on my motorcycles. I am a believer in quality lubricants.

But for a vehicle designed in the 60s that has survived (very well) on what was available, I have this nagging in the back of my head that keeps telling me to save my money and use a conventional 90wt oil. Could you explain why the Redline is worth it? And what would be suggested for the t-case and portals?

Don't mean to question your judgement I would just like to be more informed on the decision.

Thanks!

Re: 80w90 gear oil okay?

Posted: Fri Oct 02, 2015 10:06 am
by rmel
Lots of threads on the subject of Syn vs mineral oils for
all things needing lubrication.

Use the Search function with key "redline" and you will
hit most of them.

Never use a synthetic in your portals or Engine, it's
covered well on the threads.

Re: 80w90 gear oil okay?

Posted: Fri Oct 02, 2015 10:23 am
by GRCameron
There is plenty of lubricant wisdom to be found in these forums. Redline MT-90 is a GL-4 oil that is NOT aggressive toward the brass synchro rings in the transmission and transfer case. If you run a GL-5 lube in these spaces the reactive sulfur additive builds up on the surface of the rings and then separates - taking some of the brass base metal with it. Given enough time shifting suffers and a rebuild is in order.

You can run just about anything in the hubs. Redline Heavy Shockproof has been recommended by many owners. It has a viscosity like 75W90 with film thickness like 75W250. Expensive? Yes. Worth it? Most likely.

MT-90: http://www.redlineoil.com/product.aspx?pid=46&pcid=7
Heavy Shockproof: http://www.redlineoil.com/product.aspx?pid=44&pcid=8

You can order both of these through Amazon and have them delivered to your door.

Re: 80w90 gear oil okay?

Posted: Fri Oct 02, 2015 10:39 am
by pinzinator
I have run Redline Shockproof in the transfer case for a few years. It doesn't leak, and seems to work well. The transfer case, like the transmission, shifts easily at all speeds and temperatures. My only complaint is that it is hard to pour into the transfer case, and that only reflects on me, not the product. I agree that synthetics should not be used anywhere else in the Pinzgauer, as it WILL leak.

Re: 80w90 gear oil okay?

Posted: Fri Oct 02, 2015 11:09 am
by kdiqq
Dang. Well my transmission is already leaking where the shift shaft meets the box (which is why I need more fluid, so I can fix it haha) but if the consensus is that Redline goes good in the transmission, I will concede. It's all cheaper than a rebuild. And if it's anything like my other vehicles, I won't be changing tranny fluid often at all.

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Re: 80w90 gear oil okay?

Posted: Sun Oct 04, 2015 8:57 am
by Texas710
Biggest problem with redline is that it is hard to source locally, you gotta wait for delivery which is never what I like to do. Other than that, it is a great product, worth every penny. Use it in the transmission.

Don't be afraid of replacing the seal where the shifter enters the transmission, great post around here somewhere search "tranny oil leak...." about that and it really is pretty straightforward. Took me all of about an hour.

Re: 80w90 gear oil okay?

Posted: Sun Oct 04, 2015 1:57 pm
by kdiqq
Well I put the tiniest amount of locally sourced 80w90 that was GL4 compatible. I wasn't going to run it low. So I will order the seal here soon and filled it up with this liquid gold stuff haha.

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Re: 80w90 gear oil okay?

Posted: Wed Feb 15, 2017 7:50 pm
by Sonarman
I am going to give some of this a try. I will post how it does in the future.

Re: 80w90 gear oil okay?

Posted: Wed Feb 15, 2017 8:26 pm
by Haf-e
That looks like it says all of the correct things on it for use in the tranny and tcase. I'd still go with Redline myself...

Using a lift would make it much easier...