# ...gear oil change...good stuff worth the money?



## lumbee (Mar 20, 2005)

Hey guys. Did a trans swap on my 95 2wd 5 speed a few weekends ago with a rebuilt unit, and the only complaints I have is that its a little tough to get into 1st gear from a dead stop. If I'm rolling it does OK, but if I'm dead stopped I usually have drop it into 2nd, then slam it into 1st. It doesn't grind or anything...just "sticky". I used the cheap 75/90 gear oil from autozone ...I think its called "coastal"...couple bucks a quart. I adjusted the clutch, and that hasn't seemed to help any. I'm thinking of draining the oil and trying some of the synthetic stuff like this:

eBay Motors: Royal Purple Synthetic Max-Gear Oil 3 BOTTLE 75-90 (item 370060508558 end time Jun-20-08 13:26:42 PDT)

You guys think this is worth the money? Any opinions on wether it will really make a difference?


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## 88pathoffroad (Jun 6, 2004)

FYI, you need a GL-4 rated gear oil. Synthetic oil works wonderfully and reduces drivetrain drag, some people report better mileage with synthetic gear lube.


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## lumbee (Mar 20, 2005)

..talked to my transmission guy, and he says run regular 30 weight motor oil in the trans. Says 75/90 is to heavy. Will give it a try and report back...


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## lumbee (Mar 20, 2005)

...put regular old castrol 10/30 in it yesterday, and can tell an immediate difference. Much smoother, and doesn't stick going into 1st. Wonder if there can be any adverse affects long term? Think I'll change it after 6 months or so just to see how the oil looks. If no significant break down, I'll stick with it.


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## 88pathoffroad (Jun 6, 2004)

Well hey, that's different. Cheaper, too!


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## lumbee (Mar 20, 2005)

...OK, OK, I'll retract my earlier statement. Trans is back to being sticky...and maybe a little worse than with heavier old. Not sure if the 30w breaking down or what, but I'm gonna change it back to 75/80w this weekend...


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## smikster (Aug 12, 2008)

any change?


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## lumbee (Mar 20, 2005)

...yes, I went back to 75/90 and it shifts great now with no problems. I did refill it with Valvoline brand gear oil. The 75/90 stuff I put in the 1st time was "Coastal" brand??? Its autozones El Cheapo brand. The Valvoline was only slightly more expensive (less than a dollar)....but like I said it shifts like it should now. Only have problems finding reverse on occasion...but no problems with any other gears.


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## lumbee (Mar 20, 2005)

Just tought I would revive an old thread for posterity. 

I'v been using Redlines MT90 for the last few years now, and my truck shifts like a dream. I always had issues in cold weather, but I don't have this with MT90.


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## GeoBMX4Life (Mar 25, 2010)

Good to know, I'm changing mine this weekend, thanks for sharing.


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## HardbodyLoyalist (Sep 19, 2013)

You DO NOT want to use a GL-5 rated gear oil like Valvoline in these transmissions. The fluid must be rated GL-4.

GL-5 fluids contain sulfur-based additives that attack yellow metals, and these transmissions contain bronze synchros.

Your only real options are Red Line MT-90 and Amsoil MTG, unless you want to go exotic and order something like Motul Gear 300. Pennzoil makes a conventional GL-4 gear oil, but it can only be purchased from distributors, and the minimum purchase is 5 gallons.


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## smj999smj (Jan 1, 2006)

You can use GL-5 as long as it states it is "safe for yellow metals." There are a few options out there.


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## dtkana (Jun 10, 2013)

I will say this. I purchased an old 86 D21 and the guy stated the transmission had been rebuilt a couple years back, he even gave me the receipt. Anyway, I got everything ready to change all the fluids and when I crawled under the truck there was a tag wired to the transmission that read "fill with 5w30 motor oil". Thats what I did, no problems. I think it is something to do with the newer parts. Many manual transmissions use ATF.


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