Hello,
Hope im in the right spot. So i have a 50 chevy with a 5.3/4l60e swap from a savannah van i was told. Got this truck and had some issues when driving which I hope some might be able to point me in the right direction.

When I put it in drive and no foot on gas/brake..it like lurches a tiny bit , and again and again.. like almost rolling but with a little stumble or grabbing like. Hard to explain.

So when i go to drive, it doesnt seem to really instantly go..like hesitates like it is trying to get in gear. As i drive it just does not sem to shift gears perfectly. no big slam into next gear but just feels off.

The truck was done with a painless kit for wiring harness and ECU. Not sure anything about the install but trying to tell is it the swap or the gears in back as this is a 50 truck on a s10 frame and s10 rear end. The old owner mentioned something about bringing to a dyno shop to have them tweak it so it runs well. Not sure what that means exactly...sorry for my ignorance.

thanks
GP

 

From the factory it was conf. using a spec. tire size, and rear end ration-once any of that is changed, you need to recal. the ECU. The TPS could be off also.
Of course, the trans has to be good, and the conv. unlocking as it should.

 

Ok.. would a regular trans shop be able to do that or i have to find a tuning place in my area? Im in Nashville tn.

thanks

 

Sadly,I see a transmission rebuild in the near future for you,maybe early stages of losing 3-4,does it also do it if you pull it into manual 1st? Any decent transmission shop should have a scanner capable to command gears and help with a diagnosis.

 

tfi_racing makes a good point...
You mention that it hesitates when you first accelerate.
Shift to D1 and tell us if it still hesitates.
If it does NOT hesitate in D1, but does in OD, this would indicate your forward sprag is slipping, which would require a rebuild.
Unless the trans shop has tuning software with unlimited license, you will have to find a tuner in your area to adjust the tables for your rear-end and tire ratios.

 

ok will try it again today. as mentioned just got the truck and was a bit rushed for time. Will get her out, put in d and d1 and see what happens. Sure hope its just a tuning thing as it is transplanted into another vehicle.

might be a dumb question but if it came to a rebuild is there a rough idea/range of pricing on doing this. Of course it depends on what they find but just trying to see if a rebuild is better than a remove and replace as i have someone with a good trans.

thanks

 

Not so sure about this after talking with previous owner who said he just had a shop do a trans rebuild. Hes getting me the paperwork on it .

 

Sadly a lot of shops will reuse the sprags to save a few bucks.
I'm sure all of our sponsors replace the two sprags in every rebuild and even use an upgraded one for the critical forward sprag.