Delica Canada | Mitsubishi Van Club

I'm wondering if anyone can point me in the right direction with a funny noise... I am quite sure it's not normal.

The van runs pretty good in 4x2, but shifting into 4x4, engaging the auto wheel locks and then driving off normally, there is a low pitch, deep sort of rumbling and noise happening as the engine RPMs and speed increase. As RPMs increase, the green 4x4 vehicle light starts to flutter in and out (not the 'wheel lock' light, the other one). At 80km/h and 2900-3000RPM (4th gear) I can feel a bit of the vibration in the steering wheel and hear it as well. I have been avoiding using the 4x4 for this reason, it doesn't seem to have been doing it for a long time, but I couldn't say when it started. Needless to say, in 2 wheel drive, it runs much smoother and I don't notice the noise or vibration. The use of 4x4 has been when the roads and highways were particularly slick with ice and snow, no dry pavement to be found.

The van is a 92 L300 5 speed manual, with stock 4 wheel drive components, no LSD, lifted 2" with shackles and spacers/torsion re-index in the front, on bigger tires. If any of that makes a difference. I've had it for about 40,000km now, haven't changed the diff oil yet (would that be a contributing factor?). Was gonna take it in to do, but the mechanics told me that it was 'exotic' and wouldn't work on it, and would have charged $150 for a diff oil change, which seems excessive.

I'm in Fort McMUrray, so I don't have easy access to mechanics that are even somewhat familiar with these vans, though there is a higher per capita representation of diesel mechanics around than most other places.

Anyways, that's the best I can describe it. I tried taking video, but the sound quality didn't capture the issue at all.

If there's any suggestions anyone has, I'd certainly appreciate it, thanks in advance! :)

Sounds similar to mine when the u joints needed replacing in the front drive shaft.

Agree with Firesong. I replaced my u-joints about 6 months ago, and I was having similar symptoms. Crawl under the rig. Locate the front drive shaft and try rotating it by hand (in 2H with the vehicle turned off of course!). There should be some slack rotationally (less than 11 mm according to the manual, section 26-9), and no slack laterally. If it fells loose then the u-joints are done. Order parts and onto the next step which is to drop the drive shaft...

If you've done 40K kms without changing the diff oil then you're well overdue, especially if you've been four wheeling. Front diff is awkward on the L300 but doable. Remove the belly pan, remove the filler bolt, remove the drain bolt and let it drain. Clean the metal shavings off the drain bolt. Replace drain bolt and fill until the fluid comes out the filler hole. An automotive suction pump helps alot as the space is really tight. See attached pic. Don't overtorque the bolts putting them back in. Torque filler bolt to 49Nm and drain bolt to 59-64Nm. Cost of fluid is about $15-20 depending on which brand you choose. Hypoid gear oil, GL-5, 80W, 0.9L. 1/2" drive large metric sockets, a breaker bar, and a torque wrench required. Good luck!

Yah diff oil is easy to do. Drop the skid plate and loosen the drain bolt. The thing I advise is picking up a plastic hose/cap for the oil bottle. 6$ at can tire. Lets you squirt the oil into the filler hole easy.

Fs

thanks all! Have to get at it when the boss isn't around. I get tired of telling him why I won't sell Mitch to him just now. :)

Finally have gotten the chance to crawl underneath the van on the heated floor, found the front drive shaft had no fore/aft play, the forward u-joint had no play at the front diff, but the rearward u-joint had a little bit of play.

Didn't have the socket size to get at the oil, so that's still to go.

I didn't think mine had play until Manitobadeli gave it a good shake and even then it wasn't much

A bad u-joint can cause vibration and noise, and show no play at all if it is just starting to cease up. I would recommend taking the front driveshaft off, and try working each of the u-joints fully in all directions. If the motion feels rough or tight, it needs to be changed.

Jason