Allison 5sp: questionable limp

[roy67ss]

Maybe you guys could give me your opinion on the limp I had the other day. I don't believe it was the classic limp that I have read so much about although the code it gave was p0735. This was the situation with my 2005 lly. I was about 40 miles from town, the weather was cool, right around freezing with snowy/slushy/wet highways. I was in the ~100hp setting on the dsp switch. I had been on this setting for the last 3-4 weeks so I believe the adaptive learning had all been pretty well done. I came to a 4-way stop at a new construction area that wasn't paved yet. There were a few small potholes and a little washboard and I kind of rolled thru the stop because there wasn't anyone else there. I was pretty well across the road when the truck jumped up to 4th gear (I think) and the mil light came on. I had just accelerated normally when it happened and I am sure it started out in 1st. I pulled over, turned it off and restarted but the light stayed on and I had no reverse and it was starting out in 4th gear. I didn't have my code reader with me so I had to come back home to see the codes and clear it. Since then the truck has ran fine and no sign of slipping at all. From the many threads I have read the last few days, this limp usually happens when giving 'er at much higher speeds when the tranny is shifting up from 4th to 5th or down 5th to 4th and usually reverse is still there. I have also read that the code can happen if there is a problem with the transfer case but I think mine is fine. I put the pump rub fix in it last spring.

What do you guys think of the situation? Could the rough road have had something to do with the limp code? I was planning on pulling the tranny this spring anyway to do the Transgo shift kit as well as put on a new flexplate due to the starter grind issue I have.

 

[Grizzly5531]

No pro here but have you checked your trans fluid level? When I bought my truck it was a quart or to low and gave all kinds of weird codes usually under slow and off camber driving position's. Just my .02 don't everyone blow me up if this is a horrible suggestion.

 

[madmatt]

ya know I had something real similar happen to mine on a rough road. I was pulling a trailer at hwy speeds when it happened. I changed lanes to pass someone and when i rolled into ti, it down shifted and at the exact same time as the shift i hit the mother of all potholes and immediately got a po735. Cleared it and it's been fine since. have been running on the same 60hp tune since Janurary with no other issues and the trans holds it fine on 0-100+ runs any other time.