Can gear oil be used rather than ATF in Man Trans?

mduralia

Registered User
Just curious. This is the only vehicle I have ever owned that used ATF rather than 75W-90 or something similar in the transmission. My tranny gets notchy as it warms up and I just wondered if using higher viscocity lubricant would help.

I appreciate any comments.

Thanks.
 
ATF vs 90w

I'm on the opposite end of this spectrum. My tranny is full of 90w and has been for some time as I understand it. I'm not a pro at this so I can just tell you that I'm having lots of trouble shifting the car when it's at a stand-still. Looking into if the 90w is the problem.
My Mechanic tells me that (most) aluminum trans use ATF rather than gearlube. Not sure of the reason.
 
The gear oil is too thick, and can cause stiff shifting issues and grinds on speed shifting. The recomended is Dexron III and 4 oz. of Ford Friction Modifier or TransX differential addative. It is the Same thing according to Ford.
 
I'm running synthetic 75W-90W with friction modifyer (limited slip additive) in mine with good results. Lots of factory publications spec gear lube when used in climates that average above 90* F. I live in Texas and my engine makes a ton of torque. That and I will drive the hell out of it when I feel like it. I've read posts over the years of others who claimed shifting improved with gear lube so I gave it a try. So far so good, it shifts better than my last tranny did.

Vernon
 
I ran 90W in mine for years not knowing any better, and it seemed fine to me. It may be a little slower if you are into speed shifting, but otherwise I found no difficulties in any climates. (I lived in Canada originally). Anyway, it won't hurt to try.

On another note, if you are having trouble getting into gears, chances are you have issues with either syncro's or clutch engagement or both.
 
If you are going to use gear oil use Redline Synthetic MTL + their friction mod. I switched over to this years ago on my '90 5 speed after reading an article about shifting problems in a BMW. Redline recommended it at the time. I drove 246,000m in that '90 without any gearbox problems & now 185,000m in my '93. So I certainly would recommend it. Ford originally installed/recommended Dexron 3/Mercon, then changed over in later years to synthetic ATF with the friction mod. Latest I heard that was also good is Redline's synthetic ATF called D4 (I think). That's what they now recommend over the MTL. If I had to choose now and lived in the northern states I'd probably go with the D4.
 
That's funny, I'm concerned about inadequate lubrication with automatic transmission fluid. Putting gear oil into a gear box doesn't concern me one bit. Here's the deal gear oil has a lower coeffecient of friction, higher temperature range, stronger film strength, and much higher shock load. Thats why I use it in my SC when running past fast cars.

I also don't go below 20W-50 in the engine reguardless of what the owners manual says. My car doesn't meet any owners manual criteria anymore.

Vernon
 
gear oil will not enter the bearings as well as a thinner oil when cold. i do not know the difference between late and early model transmissions, but there is a reason for the switch in oils. i have seen large truck engines die from cold gear oil when first started and the clutch released on a zero degree day.
 
The main reason of switching from 90w to ATF is fuel mileage. ATF is about 10w and robs a whole lot less power. Plus it will flow faster when cold, thus helping out wear and mileage even more.

That said, I've tried Redline ATF and Mobil 1 0w30 motor oil. The 0w30 Mobil 1 seems to shift the best. Although if you're tranny's already having troubles, all bets are off.
 
Vernon...would like your opinion

Well, I've gotten a lot of answers here and the group seems pretty well divided.

Vernon - I've read many of your post in the forums and you seem to have a great deal of automotive knowledge. I'm curious to hear your opinion about the last post by BlackbirdSC.

If ATF is around 10W, what are your thoughts about using the 0W-30 or 10W-40 in the transmission?

Thanks,
 
Switching Oil

OK, I've got gearlube in my tranny now and as I said in previous posts it shifts hard. I'm going to try switching to the ATF and see what happens. I'll post the results here after.
Question: What is the capacity of the tranny? Cant find it in the manuals.
 
catching up now

if the syncro's are bad wouldn't it mean you always have trouble getting into gear, rather than my problem, only when I'm sitting still. Mine shifts fine when moving. (Remember, mine is one of the currently full of gearlube trannys)

XR7 Dave said:
I ran 90W in mine for years not knowing any better, and it seemed fine to me. It may be a little slower if you are into speed shifting, but otherwise I found no difficulties in any climates. (I lived in Canada originally). Anyway, it won't hurt to try.

On another note, if you are having trouble getting into gears, chances are you have issues with either syncro's or clutch engagement or both.
 
Holy, how do you spell them?

mduralia,
First off thanks, as for Steve's post, it seems logical to me. His statements are true and I see no reason to doubt him. If you live in a colder climate this may be the best choice. But be sure no matter what type of lubricant you use that you add a 4 oz. bottle of Ford limited slip lube friction modifyer so the sycros live.

dvruger,
Based upon your posts I think you have an issue with input shaft to crank binding, you're not getting full release. XR-7 Dave is a expert on this subjet. But common causes are,
bad pilot bearing or scored input shaft tip
loose clutch hub splines
insufficient throwout travel or length
excessive flywheel resurfacing
worn out clutch pedal bushings
air in the hydraulic line (most common and easyest to fix)

You don't have a sycro problem yet, but driving with this binding will wear them out a heck of a lot quicker than normal.

Vernon
 
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friction Modifier

I just became a little confused (don't confirm that with my wife).
Do you need to run the friction modifier with the ATF also? Or just the gear lube?

XR-7 Dave: I've blead out the clutch so that's not the issue. If and when I pull the clutch on this is it best to go back stock (I'm not planning on drag racing this car or doing much power shifting) or go with a performance? What's cheaper, and if I go performance what is the best for my application. I'm just a punch it and go kinda guy. Like it to get to speed fast when I want it to. I'm also not rich!

Vernon: Thanks for the info. I've been round and round in the local Ford garage about this and they are doing their best to convince me it's not in the clutch. It does however sound that you know what you're talking about, and I"m taking it to heart. Now it just appears I've got to save my pennies to put in a new clutch. With 100,000 on the counter it's probably time anyway.
 
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from what i've been told...

if i had to do it over again, no matter what year from 1989-95 i'd go with the cluch for a 1995. there are lots of options out there.....


but if you're on a budget.........i'd go here...

www.dialaclutch.com

This is the best deal i came across in my search for a new clutch. It is a stock LUK brand and comes with everything you need to do the job. ( I bought the one for a 1990 which is smaller in diameter than the 95, but it has been verified that the half inch or so larger 95 clutch will work on the earlier car models also and it will give it more grabbing force)


From what i've heard on the board from sources I trust, this 1995 clutch should be good up to 300 hp.

Jeff
 
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