...Ive noticed it has a weird vibration that starts when I get up to about 35 mph then disappears after 40 mph on up.
First thing I think of with a lifted EB is rear pinion angle. But this is usually a vibration under deceleration and consistent at most speeds. Not coming and going as you pass through a normal speed range.
I would definitely check the CV setup as mentioned. As well as anything else with the shaft "while it's out" as we like to say!
My C4 has a dual port modulator as it came off a bronco with emissions. I currently have both vac lines from the modulator run to the manifold on the block (not sure if this is relevant but Id thought Id share).
I think that's a good thing to mention. No idea if it's right or wrong, but maybe someone that's more familiar with the differences will let us know.
Other small issues Ive noticed but don't think they related is I noticed I have a small leak on my drivers side axel at the knuckle but its minimal.
How old are the wheel bearings? Didn't we talk about your bearings recently? I don't remember, but they are definitely worth looking into if you don't know their age.
They should be replaced not long after 100k miles (or 30 years!) to avoid a real mess.
My oil pressure I've noticed runs at about 40 under speed (35-65mph) but If at park it drops to 20 (is that normal?) oil level is good on the stick, oh and truck has all new wheel bearings and u joints
Are you using a thinner-ish oil, such as a 10w/30 or so? If so, that's a perfectly normal pressure reading. If you had something like a 20w/50 in there, I'd say it's a bit low for a good tight engine.
But even then it's still well within normal parameters and very safe. If you ever see less then 10psi per 1000rpm, you can start to be concerned. But anything above that is cake.
I did have my drive shafts gone over and the U-joints replaced.
Hmm, did you put them back in yourself? Did you notice any of the joints were tight in their sockets? I still see pro mechanics skip that last step of freeing up (centering) each joint in it's yoke so there is no binding. This does not usually end up as a vibration, but it's not a best practice either.
And how tight did you clamp down on the u-joint u-bolts? Supposed to be something light, like 10-15 lbs or something like that. Tighter can literally crimp the caps and bind the bearings.
It could be the slip joint maybe.
Doubt it. Unless it's damaged/bent, I don't see the slip causing the trouble you describe. But then again, driveshafts do the craziest things!
Could even be the tires. Not just a balance thing, but just tires if they're aggressive mud terrain types.
Paul
