Montero Sport- transmission problems common?

[wrigh003]

Hello all- this falls under "service" I guess. I have an '02 Montero Sport XLS 2WD that has been our family truckster for 10 years now. It's recently been retired to a backup role due to needing a transmission rebuild. I gritted my teeth and paid for it, since all the rest of the car was holding up pretty well. Then had to take it back again, bad brand new valve body, OK, whatever, it's under warranty and they'll handle it.

Just got word that they're almost done buttoning it up a third time, second time they've attempted this specific repair (first time was a total transmission rebuild, new valve body and torque converter too. Second repair tried a new valve body, since it wasn't quite right. Third trip was apparently the same thing- replaced the valve body again just now...). Labor and parts are covered under warranty, but I'm putting miles on my backup vehicle waiting on this thing to get out of the shop, plus the general PITA of trying to get it dropped off, picked up, etc., etc., etc.

I guess this is about 50% rant and 50% "has anybody else had this trouble?" Car was pretty much fine until 125k, at which point these transmission troubles started. I was hoping to get this thing to 200k miles before trading it away on something else, but if it's down repeatedly with transmission problems that'll never happen- I'll wind up having to trade it away before something else breaks.

Transmission guy says he's hearing this is relatively normal for Mitsubishis, apparently there are just zillions of valve bodies out there with a defective casting that makes them not work quite right. We must have been "lucky" to get ours to 125k.

[off-roader]

Your transmission guy is full of baloney! Mitsu truck (Montero, Montero Sport, Mighty Max, Dodge Raider, etc.) automatic transmissions are very reliable into the 200k mile range. I'm on my 4th Montero and have NEVER had tranny issues. I would say with over a decade of involvement with N. American Mitsu 4x4 owners, I have heard no more than a handful of problems with transmissions and in almost all cases it was due to either extreme neglect or use of the wrong transmission fluid.

As an owner you do need to ensure you service it as called for in the owners manual and don't do stupid things like shifting from Drive to Reverse while the vehicle is still moving. You also must use only 100% Mitsu compatible fluid. If you don't you will wear out your transmission prematurely.

If I were you, I'd simply find a used transmission from a low mileage rig at a pick and pull (see car-part.com) and have your current one replaced rather than try and rebuild it. Cost will likely be at most <$700 for the unit + the installation.

[wrigh003]

I hear you- this same guy told me about what you did about Mitsu transmissions lasting pretty well (minus the part about pick and pull being cheaper) when he was selling me their rebuild services. He probably doesn't remember having that conversation with me a year ago. This is the Aamco store in bham, came recommended by an indie mechanic I've used a few times. I've already spent the money, so now I'm leaning on their warranty. It's got another 2 years or probably 25k miles at this point, if it keeps failing, they'll keep seeing it. I'm crossing my fingers that this valve body replacement fixes it. They're using genuine Mitsu parts (and fluid), which has been part of the 2-week downtime for each of those repair sessions.

I was looking at pick and pull transmissions, etc., couldn't make myself roll the $800-1000 dice on a salvage unit that might not have been in any better shape than mine. Popped for the full rebuild on my trans instead, so far I'm not thrilled - can't blame the guy at the shop, though, he's doing what he said they'd do and they are standing behind their work, we're just having trouble getting good parts, evidently. Meh. Live and learn. Maybe?

I guess I'm just annoyed that all-new guts, computer reprogram, torque converter, and now three valve bodies and it's still not quite fixed.

[off-roader]

AAMCO? Yeah like the time they rebuild my 84 Supra Auto Transmission and it NEVER shifted properly into or out of gear after that! I brought it back to them no less than 4 times which was also a typical 2 week wait. That's 2 months of non-use and as a single vehicle college student, it was exceptionally painful to go through.

In the end, I just got tired of being without it so I bought a new car and NEVER went back to AAMCO.

[scrubber3]

Transmission rebuilds are an art form. I really wouldn't use AAMCO, but since you did and they are the ones doing the warranty you're gonna have to see it through. As offroader said, Mitsu transmissions are very stout and it is very uncommon to have issues with them. If they did a rebuild and they used updated parts, they need to update the controller for it as well if it's computer assisted. If not you'll end up with these same issues. Not to say this is the case, but something worth looking into.

[wrigh003]

Yeah, we're already in it with Aamco. I did a big poll of my gearhead buddies and regular folks, too, and got back a couple of "it went fine"s and no "never again"s. Small sample size- most people don't follow through on a transmission rebuild, it seems. Combine that with a ref from the mechanic that I trust, and that's where we wound up. I don't really buy transmission work as art form- it's a machine, if it's in spec it should work. If this was a hot rod or something I'd maybe feel a little differently, but it's a computer controlled box with all brand-new guts in it. It oughta just work unless the parts are defective- which is my pet theory, that there's a bad batch of valve bodies out there and I keep finding them.

It's "fixed" again, as of this morning, I'll go pick it up tomorrow (since I have to go find someone to ride with and get the car picked up) and we'll go from there. Talked to the guy for about 15 minutes on my drive in this morning, he's really not sure what's happening, though he's in touch with Mitsubishi and at least trying to get to the bottom of it. The issue of the computer/controller possibly having something to do with it came up, if that's it, we'll be back in the shop in a few weeks to get that looked at. I have seen a couple of posts by others on the internet about there being a way for that part to get wet/old/burn up down in the kickpanel and maybe skitz out a little. The shop did test it, though, and it tested as OK, so who knows. "Drive it for a couple weeks for the computer to re-learn, see if the shifts are right, then call me" is the advice this time. Same as before. I remain thankful that I have another car to drive.



Thanks, all, for providing your insight- I'll update later, good or bad.

[off-roader]

I my experience Mitsubishi does not work with independent vendors like AAMCO unless they are partnered with Mitsu which I highly doubt. Perhaps he was speaking with a 3rd party who's supposed to know mitsu transmissions.

[rxinhed]

I had two experiences with an Aamco dealer back in the 80's / 90's:

1. Had my '68 Buick GS400 and was allergic to auto-trans fluid even then. Aamco was having a special on a fluid and filter change, parents offered to pop $$ for the job. Pulled the car in, then waited in the waiting room for about an hour...for fluid/filter?? No, mechanic came back with a $2,000 dollar estimate for suspension, u-joints, bent driveshaft, loose pinion gear, ball joint, various bushings....huh? I had a custom built Ed Moore driveshaft with new joints, rebuilt rear axle, recently installed Moog suspension stuff because I had rebuilt it. The mechanic had not bothered with the job at hand, at that point, and I was able to simply leave. I let my folks know how much the place had tried to rip me a new one, then spread words amongst my friends.

2. Shortly after this experience, I began working at an auto parts store and delivering pieces to the Aamco business. I remained aloof as much as possible, because this business tried to scam everyone who walked in, the guys didn't recognize me. One of our clients worked at the Better Business Bureau, and I gave her a long winded story. The subject Aamco was subject to a sting operation by the local PD and faced fraud charges afterward. Charges were dropped, business lasted a few months longer and was closed.

Hmm. My $0.001 about an Aamco experience.

[shov3lbum]

For the Montero sport transmissions you can't use anything except the Diamond SPIII fluid directly from Mitsu, if the repair shop used anything but, they just ruined the transmission, but it will work fine after going back to the required normal fluid. We've had guys over on the monterosportonline.com forums who tried using other fluids, then the transmission always acts funny. The other posters are 100% right that the Mitsu transmissions are rock solid pieces of machinery.

OP: I suggest you post over on the monterosportonline.com forums, we have a certified Mitsu tech over there that is super knowledgeable about this stuff. Although the main site is down we still have the forum portion up, it can be found here http://msport97.proboards.com/index.cgi our Mitsu tech's name is buggzyy, he could hook you up with an answer.

[4D55 Performance]

These Mitsubishi auto trannies are bullet proof. My last Monty had well over 200k on it and the tranny shifted perfectly. These businesses have one goal, and that's to make money. It so unlike a Mitsubishi tranny to give out.