I've search the forum for my issue with no luck. Here's the deal. Lost OD while driving. Got home checked fluids. Decided to have trans rebuilt due to having 200k on truck. Transmission rebuilt by a transmission mechanic who was recommended. After install test drive truck would rev rpms up and then grab 1st gear. No good. Removed transmission and went back through it. Reinstalled and same issue. Goes into reverse no problem. Will not engage 1st gear untill rpms go up and decides to grab. Then shifts through fine. Get to a stop sign and no 1st gear. Not even if manually put into 1st or 2nd. Replaced solenoids,valve body, told electrical and to replace cpu did that and nothing. Get Trans fault on dash and code that says replace speed sensor. I've done that 2 times. I've been working on this for a couple months and am frustrated. Please help.

 

I'd suggest finding a new mechanic.

I would bring it by Ford to see if they can diagnose it.

 

I didn't see the speed sensor issue until now. This really sounds like multiple issues. The forward clutch issue we talked about and a harness or computer issue.

D

 

I'm not going to rule out getting a code like that when the forward clutch decides to not play though.

Mark Kovalsky might be a good resource on this one too for that info.

D

 

Sounds like a good idea. You are worse off than when you took it in. Sounds like he's just throwing parts at it.

 

I also think you have a problem inside the forward clutch. I really don't think there is anything electrical that could cause this.

If the shifter is in OD and you rev the engine higher than the torque converter stall speed (which is roughly 2100 RPM) and the truck doesn't move it will set a speed sensor code. Ignore this code unless it also sets the code when the transmission is working correctly.

 

Thank you all for your response. How would I go about testing the harness. Would anybody have the wiring diagram? Thanks again.

 

Hello! I have the exact same issue as you down in every manner! I have the 2008 F150 5.4 Triton. Were you able to figure out the issue? I changed out the output speed sensor and that did nothing. I also had the neutral switch changed with no change in results. Thinking of checking out the 1 2 accumulator spring. I hope you were able to solve this. Thanks