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

 

Try this, I had similar vibration between 40-50 mph. with my 2002 3.5L 4wd. My research on this forum told me to service tranny fluid. I did and it resolved the problem. If your Tans. Fluid hasn't been changed on schedule it can't hurt,
Good luck

 

Ok ok I just got a 20th anniversary last week after driving 3 other 3.8L. All 4 had the same deep droan! It does starts at 2150 rpms. On the drive home I was sure 5th or OD was missing. Just for reassurance I changed front and rear diffs and transfer gear oil. Flushed 11 quarts of SPIII ATF and added a bottle of lubeguard! Its alot better! But still there! However its only been 100 miles. Going to flush another 11 quarts at 250 miles. This worked great on my domestic!

 

Not sure if same as my 2006 model but I solved vibration by removing rubber dampener connected to trans mount. Might be worth a try.

Jim

 

I saw that block under there! I actually thought it was a bump stop for off roading! Its only connected to the cross member from the bottom. It that it. Im so tempted to add a shutter fix but an above reply said his trans light keeps coming on. I will try it.

 

It's worth a try anyway. Mine would vibrate at 2200rpm even if standing still. Pulled the dampener and no more vibration. Hope it's that simple for you.

Jim

 

Hi, i Had the same Problem with my 2003 montero limited. it vibrate at 2000 rpm around 40 mph, most the time was when was going up hill. and after a lot of research and several transmission shops look at it, they told me to try shudder fix !!!!. at the beginning i was skeptical but i gave it a try. PROBLEM SOLVE !!!! it save me a lot of money.

 

I added a bottle of Lucas it does shift alot smoother, but I still have the problem. I did see Fix on YouTube but didnt want to add both!

 

This vibration problem is caused by using the wrong oil in the transmission. See posts about what oil to use. I had my transmission overhauled 3 times before I discovered that Mitsi had come out with a new oil to address this problem. SPIII.