Quote:

Unless you want a smoked transmission and a very large repair bill, use exactly what is specified on the trans dipstick or a known exact equivilent. Fill the tranny with the wrong stuff and you will shortly be buying a new transmission.



sorry , i can't agree with this, i have a 2000 ram with a BOMBed Cummins and a 48RE , it has had nothing but dexron III in it since i starting turning up the HP , i changed out the +3 at about 39k and haven't looked back, truck has 189k on it.

i rebuilt the trans at about 89k , that was after i let someone else try out my new turbo , truck was puttting about 450HP to the rear wheels at the time , and i stupidly didn't go on the test drive . i drove it 40K miles with a slipping trans, if i did anything other than commute back and forth to work , and this was with dex 3 , only the front clutch pack was smoked .

i've got about 100k on it since the rebuild and its acting up a bit , but everything i see is pointing to the PCM or the TPS (going in and out of lockup as i can see the signal dropping out) , it's not the trans itself. the truck also has an overlap issue for the last 100k miles (i have 6 clutches in a 4 clutch drum with about .120 clearance and its not enough clearance ???), i use BW hi energy clutches and there is no signs of slipping with spirited driving on a non stock HP engine .

the +3 and +4 has additives partly because there is a surge issue with the lockup clutch , these fluids mask the issue, and also it helps the lockup clutch survive because chrysler has a poorly designed convertor, in diesels anyway and the RPM drop is about 400 rpm , the + fluid allows the lockup clutch to SLIP .