Grinding type noise on light accell at highway speeds

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I have a truck here that makes a strange grinding type noise when you bearly tip into the throttle when driving at highway speeds. I've heard this noise on a couple of trucks I've owned but was never very concerned about it. I always thought it had to do with the front prop shaft after lifting the trick and changing the position of the splines in the front shaft. That or maybe something in one of the 3 differentials.

This sound familier to any of you? I got a guy with a pretty clean 95 classic and wants me to look into it. My stance so far is that it's old age and not something worth chasing at the kind of labor rate we run here.
 

rovercanus

Well-known member
Apr 24, 2004
9,643
244
I would at least pull the driveshafts to check the u-joints. You can't always tell if they are bad when mounted. While they are off you can spin the differentials to check for anything unseemly loose.
It sounds like a driveshaft to me.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I would at least pull the driveshafts to check the u-joints. You can't always tell if they are bad when mounted. While they are off you can spin the differentials to check for anything unseemly loose.
It sounds like a driveshaft to me.

Ya I suppose I could drive it with each prop shaft out and figure out if its front or rear while I have them out to look at them. seems like the front.
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
You could always put a set of chassis ears on it to start. I would tell the guy you will spend an hour or so on it, but if it is more involved than that, it might not be worth getting into.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I thought about the chassis ears but if I do look at it for this noise I think I'm going to take the front prop shaft out of it to check those u joints better like rovercanus said. They seem tight in the truck and look good( no rust coming out of them) but if ones tight I wouldn't know it. Then I could check for any strange slop in the frt diff. While I have the front shaft out I could take it out on the highway again. If it's gone like that I gues I'll know what half of the truck it's in. Outside of all that it just looks like a big can of worms I don't want to get involved in. My last truck did this and I didn't give a shit. I just figured if something let go I would know what it is. If it fuckd up my trans because it was the front shaft I would be down to about 2 good transmissions in my garage.