transmission help, stuck in third

[gouldie1903]

hi

i have a 2000 mitsubishi montero with an automatic transmission and it will only use third gear. i've tested it and from a start to highway speed it will not shift.

i got the code read at autozone and it just said transmission problem with no code. also the neutral light indicator is blinking.

it also shifts into reverse real hard.

i took it to the garage my friend works at and the alternator is bad and it being an electronicly controled transmission may be the source of the problem.

we also think that the tps may be the problem and the computer defaults to third but that doesnt explain the hard shifting into reverse.

any help/ideas would be appreciated.

[curtis73]

I'm no expert on DSMs, but sounds like a general electrical failure to me. Pull the tranny wiring harness and look for corrosion, trace the wires and look for shorts. Sounds like its not getting any signal so its defaulting to max line pressure which makes your hard reverse shift and holding it in third.

[gouldie1903]

thank you, i'll check it out today

[UncleBob]

uh, I wouldn't recommend anything yet. You haven't diagnosed it yet, you have a couple guesses.

The light flashing is informing you of two things, one of them you already knew, which is, the computer noticed a major issue and its in limp mode, which is why its stuck in 3rd gear. Although I'm not familiar with your particular model, I can promise you there will be some data to be had from the computer.

If you are only getting guesses from your shop, its time to take it to a tranny shop before you waste several hundreds of dollars on wild guesses. As usual, it'll be cheaper to have it diagnosed from a shop that has the equipment, experience and data necessary, than playing the "lottery" with another shop.

Very well could be TPS and/or alternator, but the shop better be sure, not guessing.