My car has been shifting into OD at 40 mph and locking the converter as well. The tranny only has about 2000 miles on it and its a probuilt kit, along with a vigilante converter with less than 500 miles on it. When it shifts and locks up its very harsh and makes the car jolt until I get to around 47 mph. I have just been manually shifting for now. What could be the problem?

 

with the gears you have you probably need a lighter weight converter such as comes in taxis and police car this will raise the shift point and make for a much better feel .

 

Went I had my 2500 converter in there it worked just fine, its when I sent it in to get restalled it started to do this. I was wondering if there is anyway to program the converter to lock up at a higher speed?

 

I suspect performabuilt meant governor rather than converter

 

IIRC J.E.T made a TCC delay module that delays lockup till 4th gear.

 

It needs to be reprogramed in the chip to a higher MPH.
Shift points of the trans are taken care of by the governer.

 

i agree.

you can take out your own governor and just take off some of the weights with a drill or grinder if your careful