Allison AT545 Stuck in Reverse

[executive_36]

Allison trans technician gurus... please help me out with this if you have any insight:

I was driving my 1988 Executive 36' coach with a Cummins 'B' and an Allison AT545 pusher at approx 20mph when it inadvertantly went into reverse and ground to a halt in the middle of the road.

The Transmission will not come out of reverse, but it will simultaneously engage in 1,2,3 and 4 forward gears. Of course, with both a forward and reverse gear engaged, the trans temperature wants to heat up pretty quickly.

Here's my question: Is there anything in the transmission that can cause this problem other than a malfunctioning valve body?

Please provide me with any insight you would like to share with me, thanks so much.

 

[dbarton291]

RE: Allison AT545 Stuck in Reverse

executive_36 - 5/4/2009 3:42 PM

Allison trans technician gurus... please help me out with this if you have any insight:

I was driving my 1988 Executive 36' coach with a Cummins 'B' and an Allison AT545 pusher at approx 20mph when it inadvertantly went into reverse and ground to a halt in the middle of the road.

The Transmission will not come out of reverse, but it will simultaneously engage in 1,2,3 and 4 forward gears. Of course, with both a forward and reverse gear engaged, the trans temperature wants to heat up pretty quickly.

Here's my question: Is there anything in the transmission that can cause this problem other than a malfunctioning valve body?

Please provide me with any insight you would like to share with me, thanks so much.

A burned fourth clutch will do exactly that. When you select drive, you will have forward, first and fourth applied. That will try to lock the gear pack.

The most common cause of a burned fourth clutch other than wear out, is a misadjusted shift linkage. But once the gear pack is trying to lock, fourth is already burned.

When you get the trans fixed, make sure the shift cable is properly adjusted and lubricated. Make sure it's tight and the bracket that attached the cable to the trans is tight.

 

[executive_36]

RE: Allison AT545 Stuck in Reverse

thanks so much for your insight. time to buy a transmission kit and go through it and make it right