Transmission issues?

wilsondiesel

Member
Nov 11, 2015
190
0
16
Sedalia, MO
Has anyone seen transmission issues out of these? I have a customer that has a 2016, is having issues of no reverse engagement when parked on a hill. Fluid level and pressures are good. No codes. Truck is deleted are the only mods
 

KyleC4

Tech
Dec 30, 2016
339
7
18
Bay Area
Couple things I’ve had issues with on these. I’ve had sticking valves in the upper and lower valve body. I’ve also had the check ball get damaged and end up damaging the low reverse piston. The great thing about this trans is that after removing valve body assembly you can air check everything through the bottom of the case really easily.
 

wilsondiesel

Member
Nov 11, 2015
190
0
16
Sedalia, MO
Couple things I’ve had issues with on these. I’ve had sticking valves in the upper and lower valve body. I’ve also had the check ball get damaged and end up damaging the low reverse piston. The great thing about this trans is that after removing valve body assembly you can air check everything through the bottom of the case really easily.
Could you send me a screenshot of where to air check after removing the valve body? That would be the best way to check for a damaged reverse piston correct? Do you usually clean the valve bores like and Allison to unstick valves or just replace the whole valve body? Thank you for the info as I have found there is not much out there on these and my dealership hasn’t seen much either.
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,263
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38
Disneyland, CA
If you have valves that are sticking, you have internal problems. Whatever is sticking those valves came from the inide, not the outside.
 

wilsondiesel

Member
Nov 11, 2015
190
0
16
Sedalia, MO
If you have valves that are sticking, you have internal problems. Whatever is sticking those valves came from the inide, not the outside.
Hey Mike, is there a way in these transmissions to tell if it’s sticking valves without pulling the valve body apart? It is not throwing any transmission codes.
 

KyleC4

Tech
Dec 30, 2016
339
7
18
Bay Area
Pressure switch readings 1,3,4,5 should all read Low when in reverse. If not, then you’d have to check for a shift solenoid or pressure control solenoid for being stuck on/off or exhausting when should be applying. A check ball damaged. sticking valve etc. If trans is not slipping at all or delayed/flared shifts then I’d bet it’s something in valve body or TCM. Double check shift Cable adjustment and make sure tight. Watch IMS readings as well and make sure each time you select gears it reads correctly. L,L,H,H for signal A,B,C, and P when in reverse. Has pan been dropped at all to check for debris?
 

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