Noise under cab/bed, u-joints?
Thread Starter
|
Cargo Master
Joined: Sep 2003
Posts: 2,735
Likes: 0
From: TX
Noise under cab/bed, u-joints?
Ok, so here I am this morning cruising around the school parking lot looking for a spot. I have in first gear (automatic) for reasons other than trying to be cool.
Truck is a 78 2wd, single cab long bed, C6 w/400
Im cruising about 5 mph or so. I give it a little gas (not rhomping on it), and I hear and feel a little jerk under the cab which could also be coming from under the bed. I let off and I hear it agian. So, I keep doing this to see if there is a pattern or if it was a freak thing. It does it without fail. If I rhomp on it doesn't do it. It's only when I give it a little gas (not easing into it, but not rhomping it, if that makes sense).
Feels like there is slack somewhere, and when I give it gas it takes the slack, and when I let off the slack "returns". I would want to guess u-joints, but I'm not sure. Seems to me that if the driveshaft is spinning than any slack would already be taken out, so to speak.
What should I look for?
I will go out later and see how much play is in the driveshaft, and do any other testing that ya'll recommend.
Truck is a 78 2wd, single cab long bed, C6 w/400
Im cruising about 5 mph or so. I give it a little gas (not rhomping on it), and I hear and feel a little jerk under the cab which could also be coming from under the bed. I let off and I hear it agian. So, I keep doing this to see if there is a pattern or if it was a freak thing. It does it without fail. If I rhomp on it doesn't do it. It's only when I give it a little gas (not easing into it, but not rhomping it, if that makes sense).
Feels like there is slack somewhere, and when I give it gas it takes the slack, and when I let off the slack "returns". I would want to guess u-joints, but I'm not sure. Seems to me that if the driveshaft is spinning than any slack would already be taken out, so to speak.
What should I look for?
I will go out later and see how much play is in the driveshaft, and do any other testing that ya'll recommend.
Senior User
Joined: Feb 2010
Posts: 305
Likes: 1
u joints?
It could be a number of things, U-joints, ring and pinion, broken trans mount...
Just going to have to get underneath and move things around to find it.
park on level ground, put the truck on jack stands so there is no load on the drive shaft and rotate the shaft back and forth and look for slack.
Doug
Just going to have to get underneath and move things around to find it.
park on level ground, put the truck on jack stands so there is no load on the drive shaft and rotate the shaft back and forth and look for slack.
Doug
Thread Starter
|
Cargo Master
Joined: Sep 2003
Posts: 2,735
Likes: 0
From: TX
Ok, so short of jacking it up, here is what I have done (I'm at work).
Checked under thet ruck, no play in the driveshaft at all. Noticted nothing out of the ordinary when I pushed and rocked the truck by pushing up on the tranny as well as pulling and pushing side to side.
It does it in gear only, not in park or neutral (so would rule out motor mounts?)
More noticable when I let OFF the gas.
Does it in reverse as well.
Checked under thet ruck, no play in the driveshaft at all. Noticted nothing out of the ordinary when I pushed and rocked the truck by pushing up on the tranny as well as pulling and pushing side to side.
It does it in gear only, not in park or neutral (so would rule out motor mounts?)
More noticable when I let OFF the gas.
Does it in reverse as well.
