Hello, I have a 91 1/2 ton burb 4X4. There's a vibration when accelerating. I've rebuilt the front end before, upper and lower ball joints, tie rod ends, wheel bearings, half shafts U joints, alignment. I don't want to tell a mechanic to fix it without knowing what's wrong first and I don't want a $2000 bill. It has vague steering also. The rebuild didn't fix the steering issues. I would rather fix it myself but don't know where to start besides tearing it all apart. I have a lead on a 3/4 ton front and rear end from another Burb, is this a bolt on?
CK5
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1991 Burb front end
- Thread starter m4
- Start date
All parts should be a bolt in. Check the frame for cracks at the steering box. I don't know what you run for tires, but if they are of any size you can fatigue the steering box area on the frame. This can cause some of the problem. I'm no mechanic though.
Check around the bolt holes in the frame for any cracks. It's amazing what a difference just the ORD bolt-in brace will make with the feel of the ride. As for the vibration under acceleration, it sounds like the rear or possibly something in the tranny.
3/4 Ton Blazer
1/2 ton status
Sounds like a rear u-joint to me, why are you assuming that the front end is suspect? In 2wd, the front is not under load.
RJB44
1/2 ton status
Same problem w/vibration on my 91 GMC Jimmy
[FONT='Verdana','sans-serif']I'm not sure if you have any lift. Mine has a 4' lift (Springs). I was trouble shooting that same vibration issue. I replaced my u-joints, problem still there. I was told that it was most likely due to the fact my drive shaft was not lengthened when the lift was added. Because of the lift, the drive shaft is not aligned properly, causing vibration in the drive line. It happens from about 10 mph through about 45mph, then smooths out when up around 50 mph. I am running 35-12x50 tires. it looks like my next step is to contact Tom Wood and have him build me a new shaft. I have not been able to find a shop in the Northern VA area that is experienced in building shafts for these type trucks[/FONT].
[FONT='Verdana','sans-serif']I'm not sure if you have any lift. Mine has a 4' lift (Springs). I was trouble shooting that same vibration issue. I replaced my u-joints, problem still there. I was told that it was most likely due to the fact my drive shaft was not lengthened when the lift was added. Because of the lift, the drive shaft is not aligned properly, causing vibration in the drive line. It happens from about 10 mph through about 45mph, then smooths out when up around 50 mph. I am running 35-12x50 tires. it looks like my next step is to contact Tom Wood and have him build me a new shaft. I have not been able to find a shop in the Northern VA area that is experienced in building shafts for these type trucks[/FONT].
Thanks, the Burb is stock. The rear drive shaft is the first place I'll look. We have a good driveline shop here, I'll take it there. New U joints and balance. I hurt my back working in my shop Saturday, just waiting for the medication to kick in. Shawn
Mike D
1/2 ton status
Check the drivers side motor mount. Probable worn out. When accelerating The torque raises the left (drivers) side of the engine. Combustion pulses slightly raise and lower the engine quickly possible causing a 500 pound harmonic. Also the drive shaft angle at the trans ( or transfer case ) changes (goes down) putting more load on the ujoint yokes.
kevin400ex
1/2 ton status
not positive if the 4x4 has one, but carrier bearing in the rear shaft.
That's good info right there.
Here's an update. I had the rear driveshaft rebuilt. New U joints and balanced. The drive line shop said the shaft was balanced but the shaft was not straight, they straightened and balanced it. It still has a vibration and I can feel it in the steering wheel. The motor mounts were replaced with the new crate motor but I'll check them. The fact that I can feel the vibration in the steering wheel make me think it's in the front end area. Any ideas? What other bearings are in the front end besides the axle inner and outer. Is there one in the carrier for the axles. Shawn
