I’m hoping to get a couple of troubleshooting ideas from you guys; this issue has eluded my mechanic and most of my car enthusiast friends.

Vehicle Information

• 2002 Mitsubishi Montero Limited Edition

• 3.5L V6 engine

• Automatic transmission

• 4-wheel drive

• 170,000 Miles

Problem Symptoms

• Strong vibration that feels like it’s shaking entire car.

• Vibration only occurs when in 5th gear and RPM around 1800-2000.

• 5th gear is very smooth when above 2200 RPM.

• Wasn’t able to reproduce problem in any other gear or in neutral.

• Once car starts shaking I have two options to immediately stop it, give gas to exceed 2000 RPM or take foot off gas, if I stay at the RPM “sweet spot”, the car will keep shaking.

Troubleshooting

• No code.

• Mechanic suspected U-joint issue but he thinks the joints are OK.

• Mechanic changed transmission fluid and filter; he said the magnet at the bottom of the pan looked OK.

• Mechanic said to give the new fluid a few days and see if it helps. It’s been 3 days since I changed the fluid; I drove about 80 miles on new fluid. The vibration is still happening.

Any ideas on what else could be causing this?

Thanks in advance for the help guys. I love this car and I hate to think that it may be time to replace it.

 

Be sure that the ATF is MM fluid. Do not use any other types of fluids, even if the product says it's compatible. Incorrect fluid may cause the type of trouble you are describing (even if it's fresh). You can pick it up at a dealer, or use the below link and order it online.

STM: FLUIDS | ENGINE OIL | TRANSMISSION | ATF | TRANSFER CASE

When was the last time you change your differential fluid? If it's been a while, I'd suggest putting fresh fluid. You might also think about checking the torque converter for correct operation.

Good Luck

 

I bought "Mitsubishi Diamond SPIII ATF" from the dealer.

I haven't flushed differential fluid since I got the car, 5 years 80,000 miles.

My mechanic also suspected the torque converter, that would mean a transmission rebuild, right?

 

Yes, the torque converter is within the A/T, and servicing will require you drop the transmission.
This type of shudder can occur due to the clutch plates in the torque converter being worn out.

Below is a link to the FSM with some diagnostics you can run in order to check various functions in the A/T.

http://www.pajero4x4.ru/piii/GR00006300-23Ac.pdf

When you changed the ATF, did you do a complete flush or just a drain and refill. Without a complete flush, old fluid will remain in the system (it takes a total of about 12 quarts for a complete flush). Running fresh fluid is the best way to keep everything in the A/T running smoothly.

 

My mechanic didn't do a complete flush, he only used 6 quarts of fluid so I guess a few quarts of the old fluid stayed there. Thanks for the link Mr. Z, I'm gonna go through those diagnostics before I started messing with the transmission.

 

Since you didn't get a complete flush, I would highly recommend you do this before continuing with any other diagnostics.
Below is the link from the FSM on how to do a complete transmission flush.

http://www.pajero4x4.ru/piii/GR00006000-23Aa.pdf

Pulling the transmission pan and replacing the filter/strainer is also recommended, but a bit more involved.

Good Luck

 

I am having the same issues. sam314159 did you ever find a solution your your transmission shudder?

 

I have the same Montero Limited as sam314159 only it's a 2001 with 144K miles on it. I am having the same shuddering in fifth gear that he describes. I am considering a complete ATF flush job but I'm wondering what MM fluid is. I plan to use the recommended Diamond ATF SP III.

 

I was having the same problem with my 2003 Montero LTD, 171K mi, and had the trans flushed and refilled with Mitsubishi ATF from the dealer. The chatter was still getting worse. My mechanic added a tube of Shudder Fix from NAPA, and it took care of it. Now however, about every 20 miles the orange blinking tranny light comes on. I'm not sure if it was the additive, or what. If I stop and turn off the engine, it resets for those miles. I'm kinda between a rock and a hard place now. I'm thinking of reflushing it again.
Anyone have any ideas?
Thx, Pat

 

Shipicker - is the light you are talking about on the upper part of the instrument cluster above the coolant gauge? That is the transmission oil temperature warning light. OR is it the orange lamp in the centre of the 4WD indicator - the rear differential lock indicator. I had the diff lock blinking after driving 15 or 20 minutes and found a 1/4" vacuum line leading to the front diff actuator broken. Replacing the hose fixed the problem. It is close to the oil filter and prone to abuse. If it is your diff lock problem there is a good article on this site called Montero/Pajero flashing light fix. IF it's a tranny temp then I can't help. Good luck.