The Stovebolt Site Forums The Shop Area Driveline 57 3100 squeaky driveline diagnosis?

I finally was able to take my first drive with my "new" 57 1/2 -ton pickup. It was a very short drive, maybe a mile or so at speeds not exceeding 30 mph. It has the 235 engine and stock 3-speed tranny. I immediately noticed squeaking that increases in frequency with vehicle speed when driving in gear. There's no noticeable squeak when coasting in neutral. I hear it when going forward. I haven't heard it in reverse. The noise seems to be coming from the lower middle of the truck rather than from the rear, but I can't swear to that. My first instinct is a bad front u-joint. The "maintenance" done on this truck over the years seems to have been almost non-existent and it may have been decades since either of the u-joints have been greased. It probably would be money and time well spent to replace both u-joints but I don't like to just start throwing new parts onto a vehicle without being sure first what the problem is. Where else should I be looking in addition to u-joints? It appears that if I split the rear joint by removing the u-bolts that entire propeller shaft could be removed from the vehicle. Is the front yoke of the front u-joint simply splined onto the transmission mainshaft? That's the only spot that I can see to accommodate front/rear movement of the propeller shaft when driving. I'm more familiar with the older AD torque tube set up. This is my first "newer" truck with an open driveline. Where do I start? Thanks!

Roll the windows down and turn the heater on high. If you still hear the squeak while driving, change the oil to 10W-30 and the valve clatter will surely eliminate any hint of a squeak.

does the "squeak" change with RPM evenly?
if so then going to say driveline.
If not going to say suspension. Under load the suspension is going to have a different than in neutral and coasting.

most likely leaf springs rubbing.

Does it stop when braking but still rolling?
also look for the backing plates rubbing on something as well.

Is the front yoke of the front u-joint simply splined onto the transmission mainshaft? YES
as you can remove the rear ujoint and slide it out of trans.

The frequency of the squeak seems to correlate with the speed of the vehicle. Your mention of backing plates could be a good clue. I just got done replacing oversized front brake drums with new 11 inch drums. There are relatively unworn brake shoes that rub slightly on the new drums even with the adjusters cranked all the way down to their shortest setting. The curvature of the shoes most likely doesn't match the curvature of the brand new drums. Also I installed brand new roller bearings for the front spindles. I lubed as many zerk fittings on the suspension as I could. About half of them wouldn't accept any grease. This truck probably hasn't been lubed in decades either and suspension squeaks are certainly likely. These squeaks occur the same whether I'm on smooth pavement or a bouncy dirt road. I'll drive it some more and look for some changes that might occur when braking. Front brake shoes that haven't yet worn to conform to new drums could be a possible culprit. I haven't ruled out u-joints either. Thank you hcb3200.

Some of the u joints will have a grease fitting if they do grease them up to see if it goes away

The noise is from the brakes, not the u-joint. The "no noise when coasting in neutral" that I first reported is actually me rolling down my steep driveway with my foot lightly on the brake pedal. I did find the u-joint grease fittings- thanks KEVINSKI.