Emergency use of motor oil in a transmission

[pitzel]

Ok, so my 4T60 started slipping the other day on a long drive, and I was in the middle of nowhere, in rural Canada, without any ATF available either on-hand or closeby. I did have a couple quarts of motor oil though.

Cause of the slipping was of course low fluid from a pan leak that I somehow hadn't detected. I was able to make it home, top up the fluid, and all is well.

But if the slippage was so much that the car was undriveable, how bad would it have been to add the motor oil as an interim measure? Would a couple quarts of motor oil mixed with the ATF have destroyed the transmission? Or would it have been good enough to make it a couple hundred miles until I was able to do a pan drop and complete flush?

Any thoughts?

 

[MolaKule]

So you topped it off with ATF once you arrived at home?

The preferred fluid would have been a 5W20, but you would have had to do a complete flush.

I would recommend you do at least a pan drain and replacement ASAP since you most likely have a lot of oxidized ATF in the tranny.

 

[pitzel]

Molakule, the ATF looks great, nice and cherry red. Only needed to add a quart of ATF once at home to make the transmission behave properly. The scenario with the motor oil is, luckily, hypothetical.

The 4T60 can be very finicky if it is down a bit of fluid.

Wouldn't oxidization be accompanied by a significant change in fluid colour?

 

[MolaKule]

Not necessarily, but I assumed you were down say more than two quarts.

Small sumped trannys are working on the edge anyway and oxidation can set in because the fuid that was left has to work harder against the heat buildup.

 

[SPITMAN]

Primary cause of oxidation is heat. Living in western Canada in what are still winter conditions, it was probably cold enough to not over heat (oxidize) the ATF. Also, the clutch packs must of still had enough lubrication as to not cause clutch burn. Fix the leak, top it off and keep an eye

on it.

 

[MolaKule]

My concern with the motor oil would be that certain addives in PCMO could accelerate the glazing of clutch materials.

 

[ebaker]

Would the problem with motor oil be an additive that damages the transmission, or would the problem be missing additives an auto trans needs? I've worried about this because I may want to use the same funnel to add trans fluid and motor oil. Would the small amount of cross contamination be a promlem?

[ March 25, 2005, 01:00 PM: Message edited by: ebaker ]

 

[MolaKule]

Or better yet, carry a quart or two of ATF since it can be used in both the tranny and engine without damaging either component, as long as the engine can be refilled with the proper PCMO when you reach the nearest town.

Just don't race to town to get the fluid replaced!

 

[unDummy]

I've used a quart of motor oil in the ATF in an emergency. The tranny functioned perfectly. I also flushed the transmission when I got home and am capable of rebuilding it(so no real risk).
But, I didn't want to find out if there would be any long term effects, and would recommend a complete flush at the 1st sign of civilization.
I sold the car with 250k miles on the original tranny and about 100k miles since the oil incident.

Since the motor oil is diluted with the ATF and in a relatively low percentage, it shouldn't be a problem.

The question is: would adding a pint of motor oil be more/less damaging then the actually slipping of the transmission?

Maybe everyone should rethink the storage in the trunk. I know many people with 'this or that' in the trunk but never what they need. Plans those long trips better!
Whats in your trunk???

Since I don't care to carry multiple quarts, I keep one quart of Marvel mystery oil in my autotrannied car. That quart can be used to top off the engine, ATF, or power steering.
My manual tranny car has a quart of Lucas stabilizer. It can be used to top off the oil/rearend/manualtranny/PS-atf.

Any need for more than a quart, I recommend the correct fluid, a gamble, or a tow.
Either check off the box with your car insurance coverage options or join AAA.

 

[99]

I would never use engine oil in a auto trans, even in a emergency. They're just too expensive to take the chance on it. I would've walked, cabbed it or whatever to wherever there was a gas station, etc and picked up some ATF. Good luck with your trans.