[tony0713]

been having this problem for a little while now. when I back up, like into a parking space, I get a binding feeling when I left off the throttle. I believe it's coming from the rear.

I replaced every u joint in the truck. I had a friend back the truck up slowly while I was outside listening and it sounds like the rear. any advice?

 

[1999_7.3L]

rebuild before winter comes, if you wait till snow it will deff blow!

 

[BigFuel]

Does the nose of the pumpkin rotate up when you let off? You are sure that its not the brake shoes dragging (just asking)? 4x2 or 4x4?

 

[tony0713]

Does the nose of the pumpkin rotate up when you let off? You are sure that its not the brake shoes dragging (just asking)? 4x2 or 4x4?

I'm not sure about the nose, I will check later. I don't hear the brakes dragging but how would that make a binding feeling. and 4x4.

 

[BigFuel]

A binding feeling ought to just be the feeling of the truck resisting movement. Same thing with a dragging brake and it can happen with no noise if the brakes are cool and on one side as well as both. If there is a "thunk" with the resistance of movement then it's something deeper. While you are digging at the problem take off the rear tires and blow out the brakes. Inspect for oil leaks and the pads at the same time.

TTB (D50) or solid front axle? Why I'm still asking about the front is because weird sh!t can happen with a TTB (or a 2WD with cross beam sys.) in reverse. If it is a TTB go into a open parking lot and drive straight forward and measure the top of the tire to the inner fender right above it. Then reverse for 20 feet and measure again. Does the truck "squat" and/or do the tires camber in?

 

[tony0713]

A binding feeling ought to just be the feeling of the truck resisting movement. Same thing with a dragging brake and it can happen with no noise if the brakes are cool and on one side as well as both. If there is a "thunk" with the resistance of movement then it's something deeper. While you are digging at the problem take off the rear tires and blow out the brakes. Inspect for oil leaks and the pads at the same time.

TTB (D50) or solid front axle? Why I'm still asking about the front is because weird sh!t can happen with a TTB (or a 2WD with cross beam sys.) in reverse. If it is a TTB go into a open parking lot and drive straight forward and measure the top of the tire to the inner fender right above it. Then reverse for 20 feet and measure again. Does the truck "squat" and/or do the tires camber in?

I can feel the bind as well as hear it. clunks while binds. sounds/feels like when a u joint is real bad minus the squealing. I put the truck in the air and tried it but could not duplicate it. I also thought it could be a bad hub, until I heard it come from the rear when my buddy drove it while I listened from outside. it's a 250 so it has the d50 front, the front end is in pretty good shape as far as the wheels leaning inwards.

 

[BigFuel]

Ok, I'm with you and it's time to move into the pumpkin. Check the ring gear for abnormal wear and grab a prybar to check bearings and endplay. Do not wrap on the pinion bearing with a impact gun. there are crush to spec bearings in there and the gun will ruin them.

 

[tony0713]

I just tried to duplicate it again while I was listening to the rear end outside of the cab. I couldn't hear it although my buddy said it was doing it. before I start ripping things apart, could it be the tranfer case? is out tranfer case chain driven?

or I know that my transmission needs a fluid change. could that be it?

 

[backwoodsboy]

Open or L.S. differential?

 

[tony0713]

Open or L.S. differential?

4.10 limited slip

 

[backwoodsboy]

Does it do it while you are backing straight up, turning, or both?

 

[tony0713]

mostly always in a turn. rarely when I'm going straight.

 

[backwoodsboy]

Have you changed the fluid in the rear end lately? If so, you may not have added enough of the friction modifier.

 

[tony0713]

when I bought the truck last year it was a little low, so I topped it off and added the modifier.

 

[backwoodsboy]

Any chance the fluid is low again? L.S. clutch-packs get cranky when they don't have the right quantity/quality of fluid.
Other thought would be loose U-bolts or worn bushings in the leaf springs.

You would typically notice worn gears/bearings at highway speed first, so I doubt either of those are the issue.

 

[tony0713]

Any chance the fluid is low again? L.S. clutch-packs get cranky when they don't have the right quantity/quality of fluid.
Other thought would be loose U-bolts or worn bushings in the leaf springs.

You would typically notice worn gears/bearings at highway speed first, so I doubt either of those are the issue.

I would think the fluid would still be good, there aren't any leaks. if it were bad bushings, I would see movement while I feel the binding.

 

[BigFuel]

So the nose of the diff does not rotate when this is happening?

 

[tony0713]

So the nose of the diff does not rotate when this is happening?

no. it doesn't go up/down. but I can't tell it if goes left/right.

 

[BigFuel]

Pinion doesn't move if you try and shake it? A lumpy feeling reverse usually while turning............have you watched the motor while backing up? _might_ be a bad motor mount but not likely. In forward the transmission will torque the motor in one direction but in reverse it will torque it the other way. I'm still leaning on opening the rear end and looking at the pinion/ring gear interface to see what it looks like.

 

[tony0713]

i thought it could be a bad trans mount so I climbed under there with a pry bar and didn't have any play. I also tried wiggling the drive shaft, no play. I will have to try and see it with the hood open.