I've recently picked up an MT643 after my 545 had broken down. I think I paid $500 for the tranny, she came with torque converter, flywheel, and plate adapters.
I knew I needed additional hardware and an allison spacer. After calling everyone and their mother I came upon Weller Truck Parts out of MI. https://wellertruck.com/ I spoke to Rick from parts dept. who was cool enough to send me a couple blueprints for the MT643/MT655 and CAT3116/3126. I'm posting it hoping it can help enough people to return the favor and help me figure this thing out :Thanx:
The first blueprint doesn't require the allison spacer between the engine and transmission and the 2nd one does. At least that's what I was told.
I decided to go the 2nd route and order the spacer part number 23018900 along with the 10-Bolts 11503649.
So far what I've done is remove the AT545, old flywheel, flexplate, flexplate adapters, and torque converter. Everything came out pretty easy so I was thinking I'm off to a good start.
From there, I installed the new flywheel from the 643 that I picked up onto the cat 3116 along with the flexplate for the flywheel. Everything seemed to bolt right up. I had to remove the small ring from CAT housing, which changes the bolt pattern from SAE2 to SAE3 to allow my 643 to go right in. Now that I have my Allision spacer which is almost 2" wide and new transmission, it's time for everything to get bolted back together. Unfortunately, even with the spacer I have about a 3/8" gap between the spacer and housing. I'm not sure if I was sent the wrong spacer, I need a different flexplate, or perhaps I don't have the right torque converter. Not sure where to go from here. I'm in Beaverton OR.
I knew I needed additional hardware and an allison spacer. After calling everyone and their mother I came upon Weller Truck Parts out of MI. https://wellertruck.com/ I spoke to Rick from parts dept. who was cool enough to send me a couple blueprints for the MT643/MT655 and CAT3116/3126. I'm posting it hoping it can help enough people to return the favor and help me figure this thing out :Thanx:
The first blueprint doesn't require the allison spacer between the engine and transmission and the 2nd one does. At least that's what I was told.
I decided to go the 2nd route and order the spacer part number 23018900 along with the 10-Bolts 11503649.
So far what I've done is remove the AT545, old flywheel, flexplate, flexplate adapters, and torque converter. Everything came out pretty easy so I was thinking I'm off to a good start.
From there, I installed the new flywheel from the 643 that I picked up onto the cat 3116 along with the flexplate for the flywheel. Everything seemed to bolt right up. I had to remove the small ring from CAT housing, which changes the bolt pattern from SAE2 to SAE3 to allow my 643 to go right in. Now that I have my Allision spacer which is almost 2" wide and new transmission, it's time for everything to get bolted back together. Unfortunately, even with the spacer I have about a 3/8" gap between the spacer and housing. I'm not sure if I was sent the wrong spacer, I need a different flexplate, or perhaps I don't have the right torque converter. Not sure where to go from here. I'm in Beaverton OR.
