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! :)
