I bought my 91 from a fellow thirdgen member and it already has the t56 trans in it the problem i have is any time your foot even touches the throttle the shift light comes on i could be turning 1000 rpm in 4th and it still shows up there is no need to shift is this a problem when you do a t56 swap?

Does that car see it the same way it sees a T5?

Was it a stick car to begin with?

Your going to need to get an accurate VSS signal to the ecm if your stil runnnign the computer in the car.

Quite a few ways to do it, just do some searching on T56 and speedo should net u most of them.

Long story short, new cars have a 40k per mile pulse while ours used a 4k pulse per mile. U need to correct from the 40k to 4k and then you are all good.

later
Jeremy

If it's an originally auto trans car, then the ECM driver that is used for the converter lockup, is the same one that is used in manual cars for the shift light. In that case, it has nothing to do with RPM; it's just the ECM trying to lock the lockup up.

Either re-program the PROM, or remove the bulb.