HELP! Transmission issue.

[Spatenator]

Just had my transmission rebuilt last Summer, but lately some problems have been cropping up.
First thing in the morning, after about a mile of driving, the engine revs up to 3,000 RPM, then the transmission downshifts. I mean REALLY downshifts.
I'll cut the ignition, restart, and it sort of behaves.
After pulling the codes for the CEL, I get 0441, 0300, and 0123.
I've replaced the gas cap for the 0441, and will be checking the hoses for cracks and whatnot this weeked.
The 0300 cylinder misfire might be related to the 0441?
As far as the 0123, I replaced the TPS, but it's still throwing the code.
Any ideas?
I'm afraid if I was at highway speed, my newly rebuilt ****** would go kerblooey.

Jeep KJ Renegade
6 cyl.
4WD

 

[tlrtucker]

Try easy things first before you start replacing parts. Like you said, check for the cracked hoses back by the fuel tank, those hoses are dirt cheap and easy to replace. Don't be quick to assume that a TPS code means your TPS is bad - could be a misleading code due to another problem. I had about 6 different codes throwing out everything from bad O2 sensors, bad cats, big and small leaks, gas cap, etc. Turned out it was a section of rubber hose going into (or out of) the charcoal canister back by the fuel tank. About $1 and 6 inches of new hose and everything cleared out. But it cleared out AFTER I disconnected the battery for a couple of minutes (the codes wouldn't clear themselves). Not a single code over a year later.

As far as the ****** goes - start by checking your fluid level. Low fluid levels can cause a ****** to not work correctly. Might not be a bad idea to just drain the fluid, replace the filter and fluid and see what that does. My dad has a '76 Olds Cutlass that wouldn't shift and would barely even move. Fluid levels were full but we drained and replaced the fluid and filter and it drove like new. Then start checking sensors...

 

[Spatenator]

Fluid level is fine.