R Racing
Active member
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- 38
- Location
- St. Leonard, MD
I just finished a repair on a M917 that required a trans swap . I had a rebuilt 1 from a GL auction and swapped it out. Well the rebuilt 1 was sitting in a crate for a # of years and things do get sticky.So after starting the truck and air was up I pushed the air button and all you could hear was air pushing out of the vents in the head. The air pressure dropped from 120 to 90 in about 3 seconds. It was not a good start to a day .I tried the oil in the air line and even after 3 bottles still the same. So I called Cat ( Sugested by Bruce AKA BKubu ) and to my suprise they not only heard of the 16 speed 7155 they new it well and even had a truck with a portable test rig for it !! After several lengthy conversations with them I found out that the cat 7155 was used on I believe he said 4 other model earth movers . He said that they had in just 1 location 3 guys that specialize on the trans, And that parts were still available ! I quized him on it a bit and he himself had worked on the trans and knew it well. So while waiting from a call back from a closer service location, I pulled the umbilical cord off of the ****er ( it coms off with 3 bolts ) and poured air tool oil down the 13 ports and then hooked it back up to the shifter and let it build air ( a quick way to build air in a shop setting was use the air compressor thru a regulator to the red glad hand in the front . after shifting for a bit the big air leaked stopped !! then I had 2 small 1s from the 4th and 7th vent. after repeating adding oil to the umbilical cord 3 or 4 more times the trans was shifting like new and I was driving it around with no air leaks . I did later discover that I still have a problem when the trans is put in neutral, it doesnt want to go back into gear and leaks a bit of air.But another oil in the cord got it going again . So I now have a Cat manual on its way and I made a appointment for cat to take a look at it. So in a way its good news to know that not only the military use this trans but other Cat equipment did as well , And there are still people out there that can fix them