I'm new here and I hope I'm in the right spot. I own an '02 Montero LTD. An awesome truck to say the least! I recently ran it through an auto car wash with the high pressure under wash, of course this may have nothing to do with it but....Now I get this incredible VIBRATION in the drivetrain. Feels like I'm running over grooves in the road. The entire body shakes!! It happens when I hit a steady speed..around 40 to 50 mph. The vibration is intermittant. I've shifted into 4wd and the vibration spreads to the front as well leading me to believe its in the xfer case or trans itself. Please help!!! If anyone has heard of this or knows what to do tofix the problem please respond. THANKS!!

 

I have exactly the same problem as the previous member, with my 2002 Montero (not Sports, 3.5 liter). It sounds exactly like driving on the rumble strip on the shoulder of the road where grooves are milled about 4-8 inches apart to alert sleepy drivers. This is not a subtle vibration! The whole car shakes violently at fairly high frequency. But it does it on a perfectly smooth road. These are the features I think I have identified:

• Between 40-50 MPH.
• Must be cruising and not accelerating or slowing down
• Because it happens when cruising at constant speed it is generally on the flat or gentle slope.
• Must be in top gear (5) in automatic or manual. Does not occur in 4th in manual.
• Engine RPM about 2000.
• Starts suddenly, stops suddenly, and may repeat with a period of smooth running between.
• May occur when cornering gently or going straight.
• It started after I fitted new Michelin tyres (tires) - perhaps a coincidence.

Tire Steering and brake specialist could not find anything wrong. Careful examination reveals no loose parts. Thought it might be a constant velocity joint.

Mitsubishi garage said it is a transfer valve in the torque converter that locks the torque converter so that it cannot slip after you reach a certain speed. They thought replacing the transmission fluid would fix it. $180 for new fluid. But it still does exactly the same thing. No improvement.

I expect the next step will be a major overhaul of the torque converter. If so, is that necessary, and will it fix the problem? Is this really the cause? I think I should post this to the Mitsubishi technicians as well.

 

If its torque converter shutter, try changing the fluid.. It can help. It sounds like you may have a loose flange where your rear cv axles attach the the differential.

 

I took it to a company called "Tricities Transmission" in Johnson City, TN. They overhauled the torque converter and found the problem. There is an old fashioned fiber surfaced clutch plate that locks up the torque converter when you hit a speed of 40-50 MPH in top gear. That prevents slippage and improves power and fuel consumption. The plates had worn out with a wave or "dimpled" pattern on their surface causing vibration when it starts to kick in. Replacing the clutch plates fixed the problem. The bill was $800 which I thought was reasonable considering I could have been looking at $2600 for a new transmission.

I did try replacing the transmission fluid and all the other things people suggested but nothing worked to stop the vibration - very similar to driving on the rumble strip on the side of the road.

Thanks everyone for all your help. I hope this post helps someone else.

 

A few days after they replaced the torque converter my son borrowed my car while I was away in Canada. On the way back home he called to say my car was jumping out of gear. At one stage he was cruising on the freeway at 65 MPH 100 kph when it suddenly jumped from 5th into 3rd gear!! He had to suddenly pull over to the side of the road. At one point the engine wouldn't start. I thought all this was caused by the gear lever linkage mechanism being out of adjustment because I had noticed some difficulty getting it to engage in reverse even before I left. I advised him to slowly limp home.

When I got home from Canada, I looked under the car and it was covered in oil. The oil level in the transmission was just at the bottom of the dipstick. I didn't think it could be completely out of oil because the torque converter wouldn't work at all without oil. I called Tricities Transmission and they confirmed that. They came and towed the car back to the garage. By that stage it was un-driveable.

They stripped down the whole transmission and overhauled it. They showed me the parts. They have a stack of thin clutch plates for each planetary gear, operated by an automatic hydraulic piston. Each plate is coated in fibrous clutch plate material. One of the plates had lost its fiber layer and others had warped. The fiber had gone through the oil pump and clogged the oil channels which caused the hydraulic pressure to increase to 400 psi, at which point it blew oil out past the oil seal on the front bearing of the gearbox causing oil to leak out onto the exhaust system.

They said it is not clear which problem occurred first. The original vibration problem could have been caused by the transmission vibrating and causing a vibrating response in the torque converters lockup clutch, or it seems more likely to be the other way around. The vibrating clutch damaged the transmission and we didn't find out until after the torque converter had been replaced.

He said when they replaced the torque converter they took the sump tray off the transmission and did not find any particles, but somehow it stayed in the oil lines. I don't know why it wasn't caught in an oil filter.

The second repair (transmission overhaul) included overhauling the new torque converter in case it had bits of fiber in it. That part was covered by a warrantee on the new parts. Most of the second bill was new parts for the transmission.

Anyway I believed his story, but he had another bill for $2500 and I said he had originally quoted $2600 for the whole job if the transmission needed replacing and now the total bill was nearly $3000 with tax because it was done in two stages. So he agreed to cut the labor bill in half for the second job and that gave me $190 discount. Actually I think I was a bit cheeky asking for that as I believe his story!

 

The saga continues... After having the transmission overhauled twice and the torque converter 3 times, I thought the problem was solved. But a couple of weeks later it started rumbling again.

This occurs between 40-50 MPH and only when cruising at constant speed. Any acceleration or deceleration makes it stop. This occurs mainly in 5th gear but is detectible in 4th as well, whether it is in automatic or manual, 2 or 4 wheel drive.

The transmission mechanics have given up on it and so have I. It is drivable and doesn't seem to be getting worse. My wife says could it be engine mounts? Well anything is possible.

 

I have the same vibration, but it goes away when I put the vehicle into 4th gear. Did you find any other issues with this transmission, such as vacuum lines?