I'm trying to figure out what could be causing me to continuously break tranny pumps since my 6.0 swap. Could the crankshaft on my new '04 6.0 be a different length than my '99 5.3. I took a measurement from the back of the block (where the tranny butts up) to the converter side of the fly wheel is right at 7/8 of an inch. Does anyone know what it should be?

 

Well, the 99 and 00 cranks are longer than the 01 and up. I thought hte 99/00 cranks would still work with a 80E but didnt mate up to a 60E/65E without some modding. Read this:

https://www.performancetrucks.net/fo...d.php?t=351653

 

My crank was flush with the seal like in that pic. Could it possibly be that your flexplate isnt seating flush on the crank snout? Converter maybe have a problem causing it to rotate weird on the input shaft? Im not really sure what to say there.

 

Are you using the old TC from your 99? That may be the problem. It is sized differently than the newer ones if I remember right. To accommodate the different crank. I would get a newer model stall from Randy just to try out and see if it works. Or at least measure them and see if there is a difference.

 

check your clearance between the flexplate to
verter pads "with verter fully seated"
and trans seated to block
If its over 3/16 youre probably pullin out of the pump
and need to space it

but then again dont space it too much or it will be putting constant pressure on the pump

I think mine was 7/8 too

 

Thanks for the input guys. KANO- The distance from the back of the block to the back of the flywheel was 7/8. The distance from the back of the flywheel to the converter pads was about 3/16.
I believe I am getting too much line pressure in the tranny. I hear that line pressure is adjusted by delivered engine torque. The 6.0 is making more torque than the 5.3 which could be increasing the line pressure too much forcing the converter out of the tranny towards the engine putting pressure on the crankshaft. Which could be causing the pump rotor to break. That would also explain why I have fresh engine oil near the front and rear crank seals, and why my AC belt keeps coming off. I have to figure out how to fix this. Can't adjust line pressure with EFI live because I have the vac mod kit on the tranny. Maybe replacing the high performance boost valve with a stock one would bring pressure down enough? My head hurts...

 

if its vac modulated I dont think its a pressure issue adjusted by
delivered tq should be by vacume

did you check crank end play?
may be a thrust bearing bad

3/16 is a tad shallow
Id space it

 

Yes, I've pried front and back side of crank and seen no movement. From what I here 1/8 to 3/16 gap is right where I need to be.

 

Well, after talking to a couple of very experienced tranny guys, I'm gonna follow Kano and space my converter to 1/8 of an inch. They say it's not pressure related. Should have listened to you before Kano.

 

Like Kano said. If it has the vac mod kit, that is what adjust line pressure. Nothing else. Shimming the converter is very important. I spent a good amount of timing setting up the spacers on my flexplate. Tight spot didnt make it easy to place them in between there and threading the bolts. I also had to grind a small section off the ends my verter bolts. They were a good bit too long.