I split the case on my original trans. I put a new Jasper 4R100 trans into my truck. Now the torque converter locks up in second gear. Due to the lock up, it slams into third gear. Anybody know why it does so or any way to fix this problem?

 

I thought torque converter lock up was electronically controlled, might want to look at that.

 

Call Jasper! They will be happy to help you with some diagnostics.

 

Is it still under warranty? I would agree to call them. I rebuilt Allison trannies at Jasper about 20 years ago. Some of the builders are pretty sharp. They remanufacture A LOT of trannies there. If anyone has seen this problem before, they have. Just wondering - did you replace the cooler? I believe the cooler needs to be replaced in order for the warranty not to be voided.

 

Yes it is definetly still under warrenty. Yes I did replace the cooler. Hasn't even left the shop yet. Yes the torque converter is electonically controled. Took it to a dealer today and they reflashed the computer today and that made no difference. My trans mechanic is a Jasper dealer and they are sending him a new trans to be put in on Friday. Hopefully that takes care of the problem. Any ideas what to do next if the new trans still does it? Computer problems? The funny thing is that the old trans shifted like a Cadillac. Now with the new trans, third gear slams like a mother. I do not believe that it is a computer problem. Oh one other thing. Possibly Jasper sent a E40D trans. I know it will bolt up but will it plug in? One person says yes and another says no. Find out on Friday.

 

Isn't the E40D that POS from the earlier trucks? I know when I bought my 1994 I got a 5sp just because all of the 92-96 fords that were always sitting in front of our local tranny rebuilding shop. I'd have a fit if they sent me a different tranny to install than what should be in the truck.

 

I agree it should get what it came with and the puuters cant be the same????? thats 1st gen. too

 

The early E40D were problematic b/c of aluminum parts, poor center support, and unrefined design and programming.

The 4r100 and E40D are basically the same, a lot of the 4r parts will upgrade an e4 trans. The e40d is what led the 4r100 to be the pos it is today!

Jasper has a dedicated manufacturing facility for the e4od/4r100 trans. There are a handful of computer driven functional differences, most notably the converter lockup going from switched to modulated apply. Anything is possible, but rest assured they did not send you an old POS, all the transmissions in that family are fully updated.

The way you stated the question sounded like you did the install yourself, but your trans guy did it and Jasper is sending another unit to try and remedy the problem??? Then it should all be handled! Sucks that your truck is still down, but the issue WILL be resolved by Jasper!

 

Just work with the Jasper folks. They are pretty good at backing their products.

 

My mechanic did the install on the second Jasper trans yesterday. Amazing, it works!