Okay guys I need some help, I'm getting frustrated here!! My truck is not wanting to drop back down to 1st gear. I replaced the speedo sensor towards the back of the transmission, and then I replaced the output speedo sensor that's towards the front of it, took it for a drive and it seemed to cure the problem. Got up went to work and was working like it should, left work and back to no first gear again. When I pulled the output speedo sensor out the magnet had some metal to it and some sludge but I wouldn't consider it bad by any means. I think my governor pressure sensor and solenoid is bad, but why does it sometimes work and other times it does not? Is there something else that may cause that?? Everytime I think I have it fixed, it works for a bit and then goes back to not shifting down to 1st gear, so my take offs ate like granny style!

 

I notice it even more of I go out and start the truck and let it warm up for a while, if I get in and just go it shifts through all gears up and back down. If I start it and just let it run for 10min or so then leave then it won't go back to 1st gear

 

Think it's time to drop the pan, and see what you find. If you haven't replaced the governor pressure sensor/solenoid, might be time to do so. They get dirty, and stop working..... No, they are not self-cleaning like they should have been.

 

Ahh , I'm not alone .

Tackling this today . I'm starting with cutting out the check valve on the trans line . Then moving to drop the pan , replace the GP solenoid and switch . While there , adjust the bands (front being a possible issue) I may drop the valve body and also check valves to make sure nothing is dirty or sticking .

My guess is the GP s&s will do it . If you do end up doing this , go to Cascade transmissions and buy the whole kit for $150ish . It will include the HD Borg Warner solenoid which is recommended

 

Seller on EBay, ElectricalAdvantage, has the set for around 100 bucks.