Hi guys, I have a 93 Cummins with an auto tranny. Evrything is stock. Expressed as a percentage, how much torq converter slippage is common for these trucks? 8% 10% 15%?? 

I can't answer your question, but I think that would largely depend on what converter you have, what the stall is set up to, and how much load is on the motor at any given time (more load = more slippage). Someone might have some information about a stock powered truck with a stock trans though.

If temps are regular over 150deg with no load I'd say theres  large percentage of slipping 

Once lockup occurs there should be zero. (3rd OD OFF and 4th gear). 

 

 

No lockup in a 1st gen.

9 hours ago, kzimmer said:

No lockup in a 1st gen.

 

Depends. 

 

TorqueFlite 727 transmission No, Its a 3 speed with no lock up. This was renamed to 37RH

 

There was a 4 speed with lock up. A518 model. Which this came to be renamed 46RE later in life.

 

Then the 47RE came out in 1994. This was called A618 transmission (old name).

Right. So... No lockup in 1st gens.

A518 was a 4 speed with lock up (pretty sure).

 

It was a 4 speed (727 with an OD housing added on) but didn't have lockup until 1994 when it was renamed to the A518/46RH. At least not in the diesels.

Edited March 20, 20205 yr by kzimmer

Thanks. I remember dealing with a 1st gen with a PCM issues about 4th gear or lockup. But never got to play with the truck to see. 

I had to google it to be sure lol, It sounds like the 4 speed might have come in around 91.5?