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Doug
Doug, ASE Certified Technician
Category: Transmissions
Satisfied Customers: 8594
Experience:  ASE Certified Diagnostic Technician
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I'm ***** *****. My '99 Montero Sport is having transmission

Customer Question

Customer: I'm ***** *****. My '99 Montero Sport is having transmission issues
JA: Thanks. Can you give me any more details about your issue?
Customer: When starting the car everything works normally. But once going as soon as it shifts into 3rd gear the neutral light flashes and it won't shift back down when stopped, it gets stuck in 3rd.
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to Mitsubishi Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
Customer: Yes.
JA: OK. Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: Transmissions
Expert:  Doug replied 1 year ago.

Hi,

There is very little on this transmission you can do/diagnose yourself, so what we would want to do before anything else is make sure the transmission fluid is in normal range, measured with the engine fully hot and running.

If the fluid level is normal then we are going to be relying on getting it on a scan tool to see what is forcing the fail safe mode. Whenever the vehicle locks into 3rd gear, this is fail safe, enacted by the computer to try to protect itself. It saw something on one of the sensors that it either could not interpret or interpreted as dangerous and opted to lock the system down. When this happens, a trouble code is set in the transmission controller (different from the OBD codes, though they may be useful if there are any set).

Given that it is not happening until 3rd gear we can pretty safely rule out all of the speed sensors.... since a speed sensor problem would be evident in any gear not just one in particular.

With 3rd gear using under drive clutch and over drive clutch to engage, we can pretty safely rule out the under drive clutch and solenoid and valve, as they are also used for 1st and 2nd gear as well which again are working normally.

That would leave us with the over drive clutch to be suspicious.... and since fail safe works for third gear (bypassing electronics), that lets us know that the over drive clutch frictions and valve are probably OK.

That would leave us with the over drive clutch solenoid as a prime suspect.

Again without scan tool operation all we can do is speculate however, getting the system scanned should be a priority after verifying the fluid level is correct.

Customer: replied 1 year ago.
I have checked the transmission fluid level and it is registering full when hot. I've thought about getting the transmission fluid replaced and see if that might fix the problem.
Expert:  Doug replied 1 year ago.

I'm sorry for the delay, there is something strange going on with our notifications today apparently.

Changing the fluid is very unlikely to correct the issue given the conditions. If you were experiencing a bunch of slipping prior to the event taking place, then we might consider that... but with it just shifting into third then locking into fail safe, it is not too plausible to be just fluid related.

Customer: replied 1 year ago.
I should get the computer scanned to see what the code is? What will the code tell me exactly?
Expert:  Doug replied 1 year ago.

If you can get access to a Mitsubishi compatible scan tool to read the transmission controller, that would be ideal. If you can only get to an OBD reader (generic scan tool like parts stores use) that may provide enough information, but not always. The transmission specific codes are what really tell the story, and for those you need someone with a professional scan tool (that has Mitsubishi transmission support).
There is not enough information/symptoms as it stands to be able to make a judgment or further diagnosis without knowing what fault(s) set.

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