THE PORTAL HUB - Pinzgauers, Haflingers, Volvo 303s and more!

I AM having an unusual noise at all speeds. It sounds some what like a paddle wheel boat I have checked all my oil levels twice now and I still can’t figure out were the noise is coming from any suggestions on what I should check?

All your header bolts tight?

Not sure what a paddle boat sounds like, but I had a header bolt fall out and it sounded like I had no muffler at all.

If it's a steady splash, splash, splash sound, you just need to slow down a little. You're hitting the bumps too fast and spilling your drink.

I think It is a Bearing? On one of my hubs spent the last hour hanging out the side while my brother drove it up and down the street. Forgot to check my fluids after coming home from Denver, had one over filled.

I have seen (heard) tires make strange noises w/o any other noticable problems. A bad tire can make some very strange noises and run out ok at speed... Just another thought from the Pinz community!
Mark

Remove the engine cover and start the engine.

Check if any of the cylinder heads did blow the gasket.

I also never heard a paddle boat, but might be something similar.

Roman

If you are hearing a "thrum-thrum-thrum-thrum" noise while driving at speed, it is quite possibly the slight difference in speed between the rear driven wheels and the front coasting wheels. The main shaft is turning slower than the front of the transfer case, and the shaft is slowly orbiting around the bushing. Does the rate speed up if you mash the throttle, and slow if you let off towards coasting? Try engaging the front axle and see if the "paddle wheel" sound changes.

Jim M.
712W and 710M

I may be getting something similar on my 710. At speeds>80 kph, I begin to hear a "thrum-thrum-thrum" sound. The period is about 1 second. The truck is quite noisy at this speed anyway so you have to listen closely to detect it. You can feel it too. I only hear it when I am giving it throttle. As soon as I lift my foot off, the sound goes away. It gets worse from 80 - 100 kph. Going uphill, the period shortens to between half second and a second. Is this the same thing??

I may be getting something similar on my 710. At speeds>80 kph, I begin to hear a "thrum-thrum-thrum" sound. The period is about 1 second. The truck is quite noisy at this speed anyway so you have to listen closely to detect it. You can feel it too. I only hear it when I am giving it throttle. As soon as I lift my foot off, the sound goes away. It gets worse from 80 - 100 kph. Going uphill, the period shortens to between half second and a second. Is this the same thing??

I think so. Drive wheels that have torque on them will turn faster than a coasting wheel due to tire "slip angle" where the rubber tread blocks stretch as the are forced to push the vehicle along. More foot into the pedal, more slip, rears turn faster. Front tires are always just coasting, and even though the fronts are not engaged the main shaft is being turned by the fronts and the shaft is held by a bushing that is turned by the transfer case; I expect that if the shaft is out of balance (even slightly) and the bushing is not perfect, the shaft gradually rotates in the bushing and disturbs the shaft balance. Change the torque on the rears and the speed difference changes, hence the change in period.

It is just the nature of our beast. Unless it changes from a sound to a vibration there is nothing to worry about; at that point it would make sense to balance the shaft and replace the bronze bushing. I don't think it will leave you stranded, but highway speeds might get uncomfortable.

But this was the only thing I could think of that might be considered a "paddle wheel" sound!

Jim M.

Thanks, that sounds like my problem. What about changing the ratio of inflation pressures of front and rear wheels? Just a thought.

Jimm I think your spot on but I just had my drive line replaced with a chrom molly

The only thing is my noise is more noticeable when I let it out of gear and begine to coast.

Ok I lifted the four rear tires today and put it in drive.I got the rmp up to about 2500rpm I am getting a little rumbling noise out of the rear axle but nothing close to the sound I here at all speeds including two miles per hour I am asumming this rumbling is normal sence there is no weight on the axle? what else could I check to try and pin point the sound? ohter than tie my self to the center shaft and drive down the street.

I will say it again,tires can make some strange noises. Slipped belts and low speeds get really weired.
Mark

Forgot to ask,what kind of tires u got?
Me again,Mark