i keep getting a check eng light for 2-3 shift soleniod valve performance no 3rd or 4th gear. and yet it locks it into 3rd gear. i can make it go to 2nd but its a big clunk. so i just leave it in drive. so what gives? it does it out of no where. the other day i came to a stop at the house, put it in nutreal and turned the key off. then i started it back up put it in drive and bam CEL p0757. i wasn't even driving. could there be something loose? its done this before last year but it was when the trans got hot from poking around dirt roads at low speeds. but hasn't done it since, until now. i've got i 3 times in the past two weeks.

oh yeah, i got the CEL last night. lock me to 3rd, well came home and shut the truck off. wife went out this morning CEL still there but truck ran like normal. did this the other day too. we went to the flea market. wife had to kinda get on it for like a second then let off. i think the trans got confused and set the cel lol. it locked it to 3rd gear. we shut it off and went walking for about 2-3 hours. came back to the truck and it ran great. ???????????????? i'm confused.

 

I had the same thing on my truck sometimes it ran fine and sometimes it wouldnt shift out of 3rd even on the highway. Sometimes when it was cold it wouldnt shift out of 1st until it got warm. I got a bud with a trans shop and he changed the soleniod for me it been fine since.

 

The po757 is a fault code that is probably being cause do to a stall converter. It is possible to fix this with tuning. What you need to do is clear the code and then delete the test for this code. Vince

 

a stall can do this? can you explain why? not to question you, I would just like to know for myself. I like knowing why things do things. lol i can turn it off with hpt no problem. by the way i do have a yank tt3000 incase you didn't see it in my signature.

 

What happens is the computer is looking for a set parameter of engine rpm and output/vss signals. With the stall the input signal changes in some cases just enough for the parameters to be out of spec and the code will be thrown.

 

oh gotcha. so i just need to turn off that code. that would be why it sets it even if after a smooth shifting drive. the wife will be happy to know. she was flipping out. she has to drive this to tennesse from maryland in a couple months.