Engine Oil used in TH400 instead of Dexron

[Tow4]

Has anybody found engine oil used in the TH400 transmission of their CUCV instead of Dexron? I know they use engine oil in some of the big truck automatics but I didn't expect to find it in a CUCV.

 

[Warthog]

Never heard of that. A3s yes

 

[197thhhc]

Are you sure its not just burnt trans fluid. Does it smell like engine oil.

 

[Ken_86gt]

I Have not run into that one. Did it still work?

 

[Tow4]

It's nice and clean and looks like 15W40. It feels and smells like engine oil; it's not burnt. I could be wrong, but I remember Dexron as being more or less red.

Haven't run it yet, I need to replace batteries. I'll find out if it works next week.

 

[Karl kostman]

My 925 came from GL with 10 wt engine oil in the Allison heck that was a new one on me!
KK

 

[jw4x4]

Whether or not the engine oil will harm the tranny would be a very long, drawn out discussion. I would NOT run engine oil. Aside from the differences in lubrication properties, there is one critical factor to consider- the flash point of trans fluid is considerably higher than that of engine oil.

 

[jaxsof]

Lube oil will kill a TH400 in short order. ATF allows friction between the clutches where LO is strictly a lubricant.

LO 9-2320-289-12 still calls for Dexron II

 

[plym49]

You've posed an interesting question. If the supposed engine oil is in there, clean and not burnt, then presumably the vehicle was driving that way. Did the PO report any strange behaviors from the transmission?

It might be challenging to get all that oil/fluid out. The TC holds a lot and has no drain. The only way to get it out, short of disassembly, is to flush and flush and flush through the cooler lines. There will always be a little left (think titers), but you will get most of it out - and you will run an awful lot of ATF down the drain in the process. I'd bet a TH400 rebuild kit costs less than the amount of ATF you would need.

Also, will whatever is in there mix with ATF?

I might lean to driving the vehicle first - after you get batteries - and see how the transmission behaves cold and hot under light and heavy loads/throttle opening, and then decide on next steps based on that information.

Postscript: Either this was done intentionally and, if so, you might be all right - OR - this was someone's big boo-boo and might have been a reason the PO got rid of it. Driving a short distance should not cause any harm.

 

[supermechanic]

Can't agree with the post directly above.
15w-40 is listed as an extreme duty lube for automatics.
( Edit, Too slow,a post in between. )
(second edit) 15w-40 needs a significant warm up time before use in cold weather

 

[Ken_86gt]

Were did you see that 15w-40 is listed for use in a T400 transmission? Please post your reference

Can't agree with the post directly above.
15w-40 is listed as an extreme duty lube for automatics.
( Edit, Too slow,a post in between. )
(second edit) 15w-40 needs a significant warm up time before use in cold weather

 

[MidNightRider]

i know you are talking about the turbo 400, i had returned from Kuwait last year, spent about 7 months there working on MRAP's, and other equipment. and we were directed by the Military to flush all transmissions that has dextron and replace it with 15/40, I have been a military mechanic / Motor Sergeant for over 24 years and could not believe this. but we did as directed. when i left, it was on the table to have all transfer cases and all diffs drained, flushed and filled with 15/40. now the one reason for doing all this? the Soldiers only have to carry 15/40 instead of 15/40, Dextron and 80/90. just putting my 2 cents in on this. and yes, the transmissions in those heavy a@@ trucks operated just fine.

 

[mikes47jeep]

are you sure its not Hytrans fluid like the stuff they use in skid steers and other hydrostatic equipment? that looks alot like regular motor oil

 

[MidNightRider]

Nope, 100% sure, we would spend about 3 to 4 hours flushing out the dextron, and then we would get a 55 gallon drum, clearly marked OE 15/40, as you know the OE stands for 0il Engine, and then pump out what we need and put it in the transmissions.

 

[RedbeardTheZombieHunter]

are you sure its not Hytrans fluid like the stuff they use in skid steers and other hydrostatic equipment? that looks alot like regular motor oil

Allow me to play Captain Obvious here for a moment. Whatever is in that trans could always be drained out along with 2 or 3 flushes worth of ATF, cut with a little gasoline or a little more #2 diesel and run it in your M818 if it's a Multifuel. If you don't have a Multifuel in that beast, there's plenty of Multifuel owners here and there that'll be happy to give ya a buck or two per gallon for that drainage. Multifuels love ATF! I know it makes mine happy. Let's all be green(er)!

 

[Tow4]

I'll see how it drives. If I decide to change it, I won't be wasting 10 gallons of Dexron to flush it. I'll get out whatever pumps out and fill it up from there. In 6 months I'll do it again and call it good.

 

[plym49]

Sounds like a plan.

 

[Coal Cracker]

Somebody screwed up, DO NOT RUN 15W40 lube oil in the TH400! , if you do you can kiss it good bye. Have it flushed with a trans machine with dexron 3 , buy two cases bout 15 quarts should be fine. If you have it done with a machine you'll get everything out of the converter.

 

[supermechanic]

I stand by my earlier post. I ran two Nodwell tracked carriers(similar to a morooka), on powerline right-of-way maintenance.
Drive system was 6 cylinder chevy, th400 auto. 15w 40 motor oil in the trans.
12 years of service out of one, only half as much from the second, due to a roll over. Salvaged the parts from the roll over, put the trans into a pick up, no problems. Sold remaining Nodwell to a guy down south, it may still be running.

 

[dependable]

If it is true you can run 15-40 instead of Dextron, would it be ok to top off with 15-40? Wonder what operational result of mixing them might be. Personally, I would not try it without a reason, but would be a good emergency alternative. Have used ATF and motor oil to top off power steering pumps in past with no problems, but there is a lot more going on in a transmission.