FT Bus tranny problem.

[fekbmax]

I have a Allison AT 545 automatic transmission in my bus conversion. It's mounted behind a FT 391 and the tranny Is a Jasper re man with about 10,000 miles on it or so I was told. It shifts great, doesn't slip and pulls good. The problem I'm having is it keeps kicking the spring out of the torque converter seal. I have changed this seal 3 times now and the fist time I changed it it lasted about 200 miles. Second time around it went maybe 50 miles. Last time around it made it about 100 miles. Soon as it kicks the spring out of the seal Trans fluid will start coming out of the bell housing. It's a steady small stream. The pump seal is not leaking, it's for sure the torque converter snout seal. I have called and talked to Several truck shops, tried looking it up, talked to Jasper, and all they want is for me to have them do a over haul or check it out. I could be wrong but I do not believe it's a transmission problem itself. I think maybe the converter has ballooned or gotten out of shape and the snout isn't running true in the seal and maybe putting alot o force on it and causing it to kick the seal out.
Am I way off base here ? Any of you guys with big truck and  commercial vehicle experience have any thoughts or similar experience ?

[The Magic Ratchet]

I don't know much about Allison transmissions but, in the past, when I've had repeated failures of this seal the problem was usually with the pump bushing behind the seal or, occasionally, with the converter itself (scoring or bad surface where the seal rides). On transmissions like C-4's or C-6's the bushing can be changed from the front without removing the pump. It's probably the same with your Allison.

Lou Manglass

[fekbmax]

 Thanks for the input. Will definitely look at that on this next tranny pull.
Also Hoping I know a guy that's got a big enough lathe to spin the converter and check the snout for being true.

[fairlanegt427]

I have never had an Allison automatic trans but being a heavy hauler with a few million miles under my belt. I would try going to your local Allison dealer that specializes in heavy truck transmissions.  and or just call up Allison and talk to them.  these truck driveline companies are pretty easy to talk to to get answers to these problems.  I had a problem with my eaton my local dealer couldn't figure out so I got ahold of eaton and they helped a lot and fixed the problem talking to me and my local dealer for what it is worth.  good luck on this I am am curious to find out what your issue is.

[fekbmax]

I have gotten some good advice from a few people the other sight that really makes since. My plan I to do all of those things once I get the tranny out again. I will follow up once I can do that.

[fairlanegt427]

ok that's great it is just for my own dumb curiousity.  for what its worth