Slight "thud" on moderate accel from standstill
- Thread starter Bucky1
- Start date
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iamdub
Full Access Member
Remove the marble from the pocket in your door panel. 
My guess is it's the ever-so-common driver's side engine mount. Pop the hood and watch the engine through the gap where the back of the hood meets the cowl. Hold the brake firmly and, with the trans in D, give the throttle a sharp jab. See if the left side of the engine jumps considerably and has a corresponding thud. Confirm by checking underneath for a rust-colored chalky substance all around and on the engine mount(s).
My guess is it's the ever-so-common driver's side engine mount. Pop the hood and watch the engine through the gap where the back of the hood meets the cowl. Hold the brake firmly and, with the trans in D, give the throttle a sharp jab. See if the left side of the engine jumps considerably and has a corresponding thud. Confirm by checking underneath for a rust-colored chalky substance all around and on the engine mount(s).
You can also look under the truck at both your front and rear sway bars and end links, see if one is broken or missing, if one is it will move every time and smack under the body
iamdub
Full Access Member
I was just about to say to grease the slip yoke splines. Does it seem to do it only once when accelerating after you've braked to a stop?
Mine turned out to the front differential mounts after everything else had been eliminated.
Yes it does. About the time the truck starts to rock back, and the tires starting to turn you hear/feel it.
iamdub
Full Access Member
Classic slip yoke binding when braking then breaking loose when you let off the brake or accelerate. It's quick and easy to remove the shaft and grease the splines to at least rule that out as a cause.
HiHoeSilver
Away!
Or worn u joint.
I agree.
swathdiver
Full Access Member
My first thought when I saw this post.
I will grease my shaft then.
I know you can't always tell, but the noise doesn't sound like classic u joint. And by hand there isn't any play. Since the shaft will be disconnected, I can check it for feel.
Thank you I will report back!
I know you can't always tell, but the noise doesn't sound like classic u joint. And by hand there isn't any play. Since the shaft will be disconnected, I can check it for feel.
Thank you I will report back!
Shaft greased, thud still there. I tried to post a power brake video, but too large. Moves some but not a lot. Really doesn't make the noise power braking. Son said it sounds like it is in the right front. Sway bar and bushings look good.
I will say, what a lot of slop the transfer case and rear end have for 130k miles IMO. But those should have all the slop out of them when taking off.
I will say, what a lot of slop the transfer case and rear end have for 130k miles IMO. But those should have all the slop out of them when taking off.
swathdiver
Full Access Member
What about the front axle mounts? You didn't say whether or not you checked them...
R3cord303
Posse In Effect
I too have a thud when accelerating but haven't looked into it. It doesnt do it all the time, usually only when accelerating hard from a standstill. Gonna have a shop look at mine at some point. Feels like its coming from the ass end.
Front axle mounts?
Front differential mounts, the axles are not mounted separately
part numbers: 23104735, 23104736
How do you check em?
not really sure on that one, I would imagine you could stick a pry bar up in there and see how much play they have, I didn't check mine I just came to the conclusion after doing everything else, my drivers side one was toast, had both of them replaced. there is not a lot of room to reach up in there
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