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more manual tranny issues


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Well im back with more issues. I did the ATF flush on it and it was shifting like butter after 800 or so miles. So i drained the now dark..burned ATF out and put in some redline 75w90 gear oil. Now im back to second gear being crunchy when cold. What gives? Could it be the higher viscosity of the gear oil is keeping that worn syncro from working properly and it worked fine with the ATF cause it was thinner? Im thinking maybe i should drain out about half a quart and put in some resline. What do you guys think. When its warmed up it seems to shift fine. Its only when its cold that it has this problem..and only when im going from first to second..never if im just pulling it into second to turn onto a street or something.

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it is synthetic..redline 75w90.

You should be using redline 75W90 NS, or MT-90. The regular 75w90 has friction modifiers for limited slip differentials, that cause your syncromesh to engage slower, and grind. You could also try the redline MTL, which is more similar to the ATF in viscosity, but might be bad in temperatures over 90F (32C).

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hmm, interesting. i am currently using Redline 75w90. would that be causing my tranny to get stuck in gear? i mean i can get it out of gear but i really have to bang on it. and it doesn't do it all the time. the 75w90 did seem pretty thick to me. i think i'll swap fluid this spring and see what happens.

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Most modern manual trannies now call for ATF anyway. And the trend is growing. It's not because of large differences in the transmissions themselves, but rather large improvements in the qualities of ATF.

 

In other words, it's basically very safe to just USE ATF.

 

Also - think about it this way. When was the last time your heard of a manual tranny destroying it's gearset? You didn't because long, long before that happens the syncro's or the shift dogs are destroyed. So anything that prolongs the life of the syncro's and and prevents grinding or crunching (IE - shift dog destruction) is prefereble EVEN at a slight disadvantage to gearset wear.

 

And yet one more thing to think about - the gears in Automatic transmissions (yes, they have gears too) run in what? Yep - they run in ATF. And with modern ATF and proper flushing intervals it's not uncommon for AT's to go 200 or 300 thousand - and again most failures are not gear wear related but are due to improper shifting from the hydraulic control systems being worn or clogged.

 

Subaru ran ATF in the bonnevile Justy for lower gear resistance. Admittedly this was a race car, but it *was* runing at 125 MPH on a completely bone stock 5 speed in the hot desert....

 

So you *could* just run a high quality synthetic ATF in it and be just fine. If you like the way it shifts with ATF I say just run that. Check it for color and smell regularly, and you may end up changing the ATF every few oil changes as the manual tranny has no provision for cooling, and if you do long runs it will overheat the ATF and break it down. Simply changing it like you change your oil solves that problem though

 

GD

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hmm, interesting. i am currently using Redline 75w90. would that be causing my tranny to get stuck in gear? i mean i can get it out of gear but i really have to bang on it. and it doesn't do it all the time. the 75w90 did seem pretty thick to me. i think i'll swap fluid this spring and see what happens.

 

That's common on the 4 speeds - the one from my Brat would do that in 4th gear if I came to a complete stop. Just make sure you put in neutral BEFORE stopping and it's fine. It's due to wear on the shift dogs causeing them to bind. When they are spinning it's much easier to disengage them. Mine did that for the 50,000 that I ran it and never got any worse. I'm in the habit of stopping and parking always in neutral anyway so I never even noticed it.

 

GD

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Is there any low viscosity manual tranny fluid..say similar in viscosity to auto fluid? Also what do you think my chances are of getting my money back on this redline crap. My tranny shifts like crap again and this stuff is expensive. It shifted great with 1.89 Napa auto tranny fluid.

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As sugested I think you may just be using the wrong Redline. The "NS" stuff is what I use as it's forumated for manual transmissions, and adresses exactly the symtoms you seem to be having:

 

http://www.redlineoil.com/products_gearlubricants.asp?productID=38&subCategoryID=15&categoryID=6

 

The regular 75w90 is "gear oil" which can be used in a transmission, but contains the visco modifier for the limited slip diffs - not really a good thing for a tranny.... from their web site:

 

"75W90 Gear Oil can be used in many transmissions and transaxles; however, other Red Line lubricants have better frictional properties for rapid synchronization."

 

GD

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over on nasioc.com there is a mixture called "uncle scotty's coctail" that people are using in the wrx trannys with great results. I think it is a mix of 4 products. might be worth some consideration.

 

for anyone else interested, I found a thread talking about this coctail, http://forums.nasioc.com/forums/showthread.php?t=949794

 

1qt Redline lightweight shockproof

1qt Pennzoil Synchromesh

2qt Castrol HypoyC 80w-90

 

I've had ATF in my tranny for ~1000 miles, and am about ready to change it out to normal gear fluid. Still not sure if I want to go this route, just redline 75w90NS, or plain old GL5.

 

-Dave

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Ok everyone. I drained out the redline and put in just standard old Valvoline 75w90 non-synthetic. It still is hard to get into 2nd when cold but when warm it shifts a lot better. I think this is as good as it gets at least until its warmer than 29 out :-\

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  • 2 weeks later...

Not to hijack the thread, but this is a good read. I will do my '86 GL wagon today.

 

As it stands now, being its cold out, you can start the car...with the clutch in, let the clutch out and it will about die, due to the thickness of the oil. This sounds like a good help.

 

Car has 240K on it. Tranny syncros are a little bad going from 4th to 3rd. Curious to see how ugly the fluid will be once I get it cleaned out. I'm going to go the straight ATF route.

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