"Thrumming" noise

[Terranical]

So, the last few months my '94 T2 has developed what I can only describe as a thrumming noise - it only happens between 2000rpm and 2500rpm and sounds like a blowing exhaust (it's not, it's just had a Spanish MOT), and creates a vibration which can be felt through the floor, up to 2000rpm, smooth as silk and over 2500, the same. This happens in all gears and whilst accelerating or on overrun.

At first I thought it might be a universal joint, so I pumped a load of grease into all three grease nipples, this made no difference at all.
I also thought possibly a wheel bearing, although I would assume that would be constant, not just in a narrow rev. band, plus worn wheel bearings would have shown up in the MOT I would have thought.

Anyone got any ideas? :nenau

 

[stinka]

Prop UJ ? Only because mine started like that, and now its unbearable and literally hanging off

 

[Lazy-Ferret]

First thing, 3 Grease Nipples??? Shouldn't you have 4?

Anyway, the only thing I can think of that comes in at that sort of revs, would be the turbo.

 

[Terranical]

That was my first thought, particularly when greasing them produced no old grease the other side, but I would have thought that being freshly greased up would have made a difference to the noise, but it hasn't, thanks for that anyway Stinka.

 

[Terranical]

First thing, 3 Grease Nipples??? Shouldn't you have 4?

Anyway, the only thing I can think of that comes in at that sort of revs, would be the turbo.

4? One on each propshaft UJ and one on the transfer box drive I thought!

 

[Terranical]

First thing, 3 Grease Nipples??? Shouldn't you have 4?

Anyway, the only thing I can think of that comes in at that sort of revs, would be the turbo.

Being something of a newbie on anything to do with turbos I wouldn't know where to start looking for a problem there, apart from ensuring all pipework sound and clips properly tightened!

 

[Fez_uk]

Probably propshaft UJs, I'd be tempted at disconnecting the rear one and running in 4wd mode with just the front prop attached.

Only do it for a few miles, see if the noise goes.

 

[Terranical]

Probably propshaft UJs, I'd be tempted at disconnecting the rear one and running in 4wd mode with just the front prop attached.

Only do it for a few miles, see if the noise goes.

Interesting!!

 

[Fez_uk]

Interesting!!

One of landy tricks I have picked up along the way. :thumbs

 

[rustic]

4? One on each propshaft UJ and one on the transfer box drive I thought!

On the older Mavs and Terranos, 2 grease nipples on rear prop shaft, one on each uj, and 3 on front, one on each uj, and one on the sliding joint.

Later Terranos don't have them on the front, that's why they wear out as they also have fixed hubs, not auto hubs:doh.

 

[Terranical]

Good man - first time I have greased the UJ's (in 30,000 miles of ownership - oops!) and seeing one nipple on each UJ assumed that was it - looks like a trip underneath tomorrow, and we've got 28 degrees forecast!!!
Thanks Rustic.

 

[cncfabs]

Probably propshaft UJs, I'd be tempted at disconnecting the rear one and running in 4wd mode with just the front prop attached.

Only do it for a few miles, see if the noise goes.

Whats going to stop all the oil running out of the gearbox:doh

 

[Fez_uk]

Whats going to stop all the oil running out of the gearbox:doh

Good point, forgot they are not the same.

 

[Lazy-Ferret]

On the older Mavs and Terranos, 2 grease nipples on rear prop shaft, one on each uj, and 3 on front, one on each uj, and one on the sliding joint.

Later Terranos don't have them on the front, that's why they wear out as they also have fixed hubs, not auto hubs:doh.

Bum, just did mine today, while MOT preping, but only found 4... I found one on each UJ, e.g, 2 on rear prop, and 2 on front prop, where is the other one, to the front, or back of which drive shaft?

 

[Banshee]

Right, I'm going out in a bit and am going to take a video of the noise mine makes, I'm beginning to think my noise is coming from the prop

Some of the longstanding members will know I've had a pesky noise from the underside of the truck for ages and am still yet to find the source, so far I've checked;

Load Sensing Valve
Rear Wheel Bearings
Spare Wheel Bracket
Fuel Tank Guard

The only thing that sounds remotely the same when underneath and smacking it with a hammer is the Propshaft, I'll upload the video when I get back and see if you guys can shed some light on it again

It only happens at low revs for example cruising at 30mph in 4th gear and then accelerating

 

[kitchenman]

I have that noise up to around 1500 revs, does not show up at higher revs.

Will be interesting to know a fix.

 

[Banshee]

I have that noise up to around 1500 revs, does not show up at higher revs.

Will be interesting to know a fix.

Is it a really loud rattling sound?

 

[kitchenman]

No a sort of drumming noise, only there at low revs

 

[solarman216]

Whats going to stop all the oil running out of the gearbox:doh

stuff some rag in it, good for a test run, Rick