m917 dump transmission shifting problems

[thetruckguy]

I am trying to help a friend fix his m917 dump. the transmission will not shift into reverse. He said he was pretty sure it was not shifting into some forward gears also. It is a 16 speed caterpillar transmission. part number 5R3855, serial number 72S3680.anyone familiar with this?

 

[simp5782]

There are a good many threads on the CAT 7155 not shifting into gears. It has a lot of Orings and poppets in the valve body.

Best and easiest way is the remove the umbilical cord off the shifter and fill each port on it up with air tool oil. Steadily pour it even in the little lines. You can also pop off the air line on the passengers side tank that feeds it and fill it with air tool or marvels mystery oil. You may have a few dried orings that are stuck.

Member RRacing is the guru on these and he is located in Maryland. He has some replacement valve bodies that are easy to swap out thru the access port in the floor if you get to that parts replacement.


https://www.steelsoldiers.com/showthread.php?168626-cat-7155-issue