I love my Monty and put 270 K on her. It's been through hell and back. I do tons of snow boarding and 4x4'n, so it get's beat up. So after all these years and being dependable, I'm at a cross roads. I started having problems last Nov 09, weird/strange problems. So, I ended up taking it to a mechanic and they said it was the "Harmonic balance". So I had them replace it. That cost me $823 (including belts). Ouch!. When I got it back, it is now shifting hard between all gears and the Tachometer is not working. I took it back and they said they looked at it and it now needs a new tranny, about $1600 more.

So get this. I get Monty back and now it shifts fine, with a little hard shift between 3rd and 4th. And now the Tachometer is working. So, I've been web searching and all the best answers are on this forum. There are no fault codes.

I'm having the automatic transmission fluid replaced with the Diamond (per recommendations from the forumn) and the filter completely replaced. It's only (only... ha...) $200.

From what I gather from reading if this doesn't clear up the hard shifting from 3rd to 4th(without making the problem worse again) my options are the following:

1. Limp mode (tranny goes into limp mode until problem or sensor is fixed)
2. vehicle speed sensor
3. go to dealer
4. replace tranny.

I'm in LA and sure would appreciate a shop or dealer recommendation. Or any DIY recommendation. The last thing I want to do is get rid of her unless this is her last leg. I've had this serviced at Van Nuys Mitsubishi until they closed. Now I just don't know what to do and I'm getting antsy to tear it up in this new snow.

 

Got it back today from the shop after the automatic transmission fluid change. All the hard shifting is gone and there is just a tad late shifting between 2nd and 3rd. Seems like it should shift at 30-35 (~2500 rpm) and is shifting between 40-45 (~3500 rpm). All other shifting problems are gone.

Also found a Independent Mitsubishi Repair Specialist - GVW. I spoke to the guy and he said there are 2 sensors. A Engine speed sensor (which explains the tach not working) and a transmission speed sensor (which reminded me that my cruise control is no longer working) and either or both could cause late shifting.


Does anybody know about these relating to late shifting?

 

Carey

I have no experience with sorting out the transmission issues. Just wanted to thank you for your post as I jave learned a couple things to keep in mind for my auto trans Monteros. I will be following along to see what more I can learn.

Regards
Tom

 

Thanks tdf. BTW, related to late shifting. So, I was thinking about how long it has been since I did a tune up. I put Bosch platinum 4's spark plugs 140,000 or so miles, or 10 years, ago. I guess they are suppose to last 100k. So I did the deed. The old ones weren't that bad. A little ashy, white grains of powder around the tip, which I consider normal for 270+ miles. I'm shocked it's not worse, indicating rings or valve problems.

I replaced them with new ones and noticed a little extra kick and the late hard shifting is gone. I'm guessing that the new plugs are giving me 1-2 hp and that little extra umph is helping the shifting. When it's cold, the 3rd - 4th gear lag will linger back in. But, if I just let off the gas a little over 35 problem solved (and only when its cold). I'm thinking a temperature/idle/fuel supply sensor needs to be replaced. Or maybe plug wires and rotor. But I'm not going to worry about it. I went from rebuilding the transmission for $1600 to tranny fluid, filter and plugs for under $300. I'm pretty happy bout that.

 

Carey,

Couple of questions regarding your maintenance history. I assume you have had this truck since new? Have you regularly kept up with ATF changes? What was the old fluid like when it came out? I'm thinking maybe the valve body passages could be a bit dirty. Might want to try adding about a pint of Marvel Mystery Oil in the transmission to see if cleaning it up will help a bit. Having said that, you can use any universal ATF meeting SP-III or Dexron spec. I personally use Mopar ATF +4 in mine, which is a full synthetic, and it holds up better than SP-III based on used oil analysis.

Having said that, have you checked your TPS?

 

Hi Skiddy,

I've have had the truck since new and have somewhat mostly done ATF changes (I'm guessing every 100k?) The fluid came looked not that bad, it was dirty, but not that bad. I think your right about the valve body passages. I'm hesitant with pouring Marvel Mystery Oil, just preference. I'll be sure to use it before my next change and maybe Mopar too. I'm still thinking that speed sensor is going bad. Is that the TPS you are reffering too?

So, this week end I was trying to solve my squeaky sound. I replaced all 4 shocks and it helped some. Then I bought a can of white lithium grease spray and just sprayed the bushings while my friend rocked the car. That didn't help.

So, then I sprayed a half a can of WD 40 into the little grill below the bumper. I guess there is a plate and some sort of stabilizer arm in there.

That was it, no more squeaky sound. Does this mean I should replace something somewhere?

 

Carey,

If you don't feel comfortable using Marvel Mystery Oil (MMO), you can try Auto-Rx. I personally use both, and add either one 6,000 miles prior to a transmission fluid change. I also do a cooler line flush, so I have 100% fresh fluid in there.

As for the VSS, it very well may be faulty but I cannot guarantee that it is. The TPS (Throttle Position Sensor) monitors the position of the accelerator, and works alongside the VSS to determine gear changes. You might want to take the truck into a dealership, so they can use a Mitsubishi MUT scan tool to check for codes in the TCM.

As for the squeaks, when do you usually hear it?

 

Hi Speedy,

Thanks for the Auto-RX idea. I used that before and had great results and since had forgotten all about it.

The VSS is not displaying the engine speed, so I found the mauanl on how to test it.

Also, here is the TPS adjustment and checking. It doesn't look so hard, so I'll give it a try this weekend.

The squeaks where heard all the time, even when the car was off and I shut the door. I found a picture of the places I sprayed and marekd them with a red arrow. (I hope these pictures go through)

 

Hi Carey,

Best of luck, keep us updated! Did you tighten the bolts after spraying WD-40 by the way?