I got a rotational knock under the front of my truck at low speeds. I thought it was a rotor but they seem Ok. I can hear it if i'm rolling slowly in heavy traffic but it seems to go as you get faster. Everything else on the truck seems to perform fine, i did 500 road miles today and it was fine except for this noise

If i engage/disengage the 4wd it stops for a while. There also seems to be an intermittent noise like some thing switching on and off under the truck.

I dont want to keep driving it an damage something as the parts are hard to get here in the UK and there is no dealer backup for truck.

Truck is an 04.5 3500 SRW QC 4x4 with low miles (45k) thats hardly been off road.

Thanks in advance for any answers

Andy

 

It kinda sounds like your U-Joints. In 2WD, drive slowly while turning real hard in one direction, then the other (stop to stop). The knocking may be more prominent when turning hard.

 

I tried that first, i'm pretty sure it's to do with the 4x4 or transfer box

 

anyone got any idea? thanks

 

Mine was doing a similar thing and it was my axle u-joint. I am fiarly sure just looking and seeing rust and/or lots of particles around the joint was fairly obvious what my trouble was. My u-joints from transfer to front axle are still stock. Could one of these be failing on yours?

I have not heard of someone having trouble with the transfer case other than a couple racers that busted parts up.

 

I'd also guess one of the axle U joints, or possibly the front drive shaft...

 

Yep, it was the u joints. Both sides are bad on the front axle.

Who sells these online, and ships worldwide.

What are they like to do?

 

I don't know who sells them on line, but there was a great thread with photos about how to replace ball joints. Since this involves removing the hub and axle, I thought it would be helpful.

https://www.dieseltruckresource.com/...ght=ball+joint

You may as well check the ball joints, since if they are getting a bit loose it would make sense to change them while it's apart. Also, put some anti-seize on the hub before you reinstall it.

Lastly, glad you found your problem, and that it isn't something too serious.

 

Motorama, how did you find out that it was the u-joints? I had a low speed knock like you described but my u-joints look fine. When my rear one went out, I could see wear around the rubber bushings over the bearing cups. My front ones appear to be fine.

 

We lifted up the front of the truck and got under there, you could hear them clicking when you spun the wheels and they dont look too pretty either.

 

I believe the part i need is Precision #464 but how many do ibuy to do both sides. 2 or 4?