Using ATF oil in a differential?

[320touring]

Following on from Darin's excellent thread re Gearbox oil viscosites Effect of gear oil viscosity on transmission efficiency (Metro owners take note)

I got to wondering...

could you run ATF in a differential?

The Gertag gearboxes on my e30 and e36 are happy enough using ATF to lubricate them-makes he shift much lighter from cold, with no adverse effects..

so, has anyone ran ATF in an open (NON lsd) differential?

if so, what happened?

[drmiller100]

the drag racers do it for a few hundredths of tenths. Works for a bit, but causes LOTS of wear really fast.

better idea would be engine oil - it has some cushioning and lubrication. ATF has very little lubrication.

[320touring]

Originally Posted by drmiller100

the drag racers do it for a few hundredths of tenths. Works for a bit, but causes LOTS of wear really fast.

better idea would be engine oil - it has some cushioning and lubrication. ATF has very little lubrication.

Thank for the info!

I may just try ATF in the Gearbox- known to work

and something like a 15w40 in the diff?

[oil pan 4]

Differantial assembly units can use ATF.
Millions of front wheel drive cars do it every day.

Most "open" spindle gear sets appear to do just fine in ATF, the GM zexel-torson LSD is approved for use with ATF. I don't see why detroit locker and varrious aftermarket lockers would have any problem.
Any spindle set with clutches such as a GM posi unit wont do so well with ATF.
The ring and pinion gears shouldn't really care what kind of oil they are in so long as they stay wet.

I think you could have problems if you put ATF in a differential used on applications other than light duty car stuff (I wouldn't mind being wrong on this).

It seems that on paper it should work but I have never found any one that has ever tried it.

Never try swapping ATF for gear oil in a manual transmission.

[320touring]

Originally Posted by oil pan 4

Differantial assembly units can use ATF.
Millions of front wheel drive cars do it every day.

Most "open" spindle gear sets appear to do just fine in ATF, the GM zexel-torson LSD is approved for use with ATF. I don't see why detroit locker and varrious aftermarket lockers would have any problem.
Any spindle set with clutches such as a GM posi unit wont do so well with ATF.
The ring and pinion gears shouldn't really care what kind of oil they are in so long as they stay wet.

I think you could have problems if you put ATF in a differential used on applications other than light duty car stuff (I wouldn't mind being wrong on this).

It seems that on paper it should work but I have never found any one that has ever tried it.

Never try swapping ATF for gear oil in a manual transmission.

Thanks for confirming that ATF SHOULD be ok in an "open" differential (no clutch plates)

My friend who builds Diffs for a living has confirmed that ATF should work on in my differential- So I reckon it may be worth a shot- now to get the time to do it!

Its also common practise for us BMW folks to run ATF in the gearboxes here- makes cold shifting much easier- I have no Qualms about doing that-or I may try engine oil as a half way (Darin seems to suggest that the oil in the metro trans is similar to 5w30 engine oil..)