I have heard that it is not necessarily a good thing to add a shift kit to my old '96 12 valve truck's tranny. I wonder why? I think the transmission should be the 48RE but that should not matter right? Isn't the idea to increase line pressure and not slip the clutches so much? Why would this school of thougt be any different for a Cummins powered truck than a gasoline truck? I think it would be more efficient at putting the power to the ground so to speak...Any thoughts would be welcome!

 

Where did you hear that?

 

should be a 47re the 48re was the trans used with the cr's

 

that information was given to me by a local tranny guy that seems to know his stuff but who knows...he does mostly cars and not pullin' stuff! I guess the thing to do then is to order a shift kit?

 

The seals in the older trannys aren't strong enough to handle the increased line pressure of some shift kits. The 47rh's can't handle much at all. A 96 47re will handle more, but with 14 year old seals, it's still a gamble depending on how much the shift kit increases the line pressure.

 

yeah I think that's what he meant, maybe that the old seals might be weak. The tranny was rebuilt about 3 years ago but who knows. It's a gamble...