Trans issues after cumins repower
 

Hey gang, i haven't been around in awhile because i am been taking my truck apart about every 150 miles. The TC keeps failing and cracking at the snout and this time it broke the snout off. This my third TC and i am losing my mind. The trans is a turbo 400 with destroked adapter plate, fly wheel in front of of it. My spacing seems to be correct, what else could be wrong>? I called destroked and they dont have an answer for me or the guy who did the swap. I am on my own yet again with this truck.

Chris

First thought is alignment but what kind of mounts are being used on engine and tranny . Have you checked run out on flex plate yet ?

I have to agree with alignment
 

alignment ??

I would take a dial indicator and set it up to measure the run out on the torque convertor. on the end where it goes into the pump you should not have no more than .003 run out I would think I would suspect the flywheel-flex plate if they use an adapter for that check that so it doesn't have a wobble

another thing is your torque converter rated for diesel I really don't think a gas one would stand up to the abuse of that the cummins will put out

if my memory is correct didn't some of the old bread trucks use a th400 that might be a better option and use that torque converter

Chances are you have a BAD U joint on the slip yoke! Or your U Joint is out of time with your back u joint!

The guy who did the swap makes his own mounts. The convertor that was in it was a 6.2 convertor from Monster with flange reinforcement. The bread trucks have a TC out of an allison 545 trans. They are the same diameter. I am gathering when u say run out, how much play is in the TC when its mounted to the flex plate?

As for the 3rd response, How would the bad u joint cause the TC to crack at the snout?

When it broke this time it happened when i shifted out park and into drive. I heard a metal sound like a TINK and the all hell broke lose on the ground and under the truck.

I would guess it's either flywheel/flexplate, or possibly somthing with the input shaft in the trans. Runout would be the out of round movement of the snout caused by a bent flywheel,etc. Pictuire the snout of your tc spinning in an egg shaped pattern. :c:

what flex plate are you using? is it external balanced or internal? if chevy it can be either.

The flex plate also came from DeStroked. I am unsure how its balanced. I understand what run out is now. My new mech thinks it has to do with spacing. He said the trans seal look squished making him think when the trans was installed again it was forced together. As for input shaft, how do you know if that is bent? The trans was rebuilt so i figured that would have been noticed in that process and replaced.

trans
 

when you install trans to engine you should be able to spin the torque converter before you put bolts in if you cannot then it is to tight

as you are tightening the tranny continue to check your torque converter to make sure it is free on a gm you should have about .250 maybe a little less between the flex plate and torque converter that you actually pull it into the flex plate

as far as the input your tranny guy should have checked that might not be a bad idea since its out to take it back to him tell him your problems and have him check the tranny over good

Alright if the spacing off then what do i do?