Rear end play

[Chebbyfan]

Ok, I looked thru the first 20 pages of the topics her and couldn't find what I felt I needed to solve my problem.  My truck is an 04, extended cab, 233,000 miles on drivetrain, rear disc brake truck.  When I brake, the rear end feel like it loads up and unloads (for lack of better terms) when I release the brakes.  I replaced u-joints not quite a year ago, along with brakes and everything looked good.  I filled the drive shaft with grease before slipping back onto transmission end, couldn't believe there was no grease zert in that slip yoke to do that.  Seems like it just started this this summer, but I don't know where to look.  Could the shocks be letting the axle wrap just a little bit when braking?  The truck is fairly clean underneath for the miles and environment.  Its just annoying I can't figure this out.  Thanks for any help.

[txab]

There is a reason for no zerk on the yoke at trans. You don't want the grease to be mixing with trans fluid. Put a zerk on there and somebody would pump that thing full of grease.

 

Axle wrap was a problem on the early 900 series. They came out with a new yoke with nickel splines, iirc. Is the truck lifted changing the drive angle, pulling the yoke further out of the trans? Seen examples of shaft barely in the trans. It caused a sticking situation. You got a 1 piece shaft? Did you clean the splines? You can lightly grease the splines.

Edited December 18, 2021 by txab

[Chebbyfan]

Yes, its a one piece driveshaft.  I made sure splines were good, then put some grease in there before sliding in the trans.  Thank you for your reply txab, I'm really trying to find this problem..............

[richard wysong]

stock suspension? have you done a close inspection of the springs and hangers, bushings? If it has spacer blocks it may have weakend the spring with the extra leverage. you may be able to add a short leaf to the top of the stack to compensate

[Supreme Pizza]

"rear end feel like it loads up and unloads"

 

I'm not sure exactly what you mean.

 

Can you describe the problem in a different way?

[Chebbyfan]

6 minutes ago, Supreme Pizza said:

"rear end feel like it loads up and unloads"

 

I'm not sure exactly what you mean.

 

Can you describe the problem in a different way?

Its like when I put on the brakes, the rear brakes will stop the axles, but then releasing the brakes, the brakes release and the truck lunges forward like its releasing sprung up weight and it clunks a little bit.

 

The suspension is all stock, but I will have to check spring bushings and mounts. 

[CamGTP]

Seems like it could be a issue with the rear calipers or the parking brake inside the rear rotors.

[Supreme Pizza]

1 hour ago, CamGTP said:

Seems like it could be a issue with the rear calipers or the parking brake inside the rear rotors.

 

Ya, I was thinking the same think. Something going on with the brakes maybe. You could test it by stopping the truck (from 10mph or less) with the parking brake only, and see if that changes anything. You could also go down a steep hill with the engine in neutral, come to a stop, and let off the brakes so the truck roll forward again, to see if that changes anything. Maybe jack up the rear end, and check for brake drag, then put it in gear (with rear end still off the ground), and see if the problem goes away under those conditions.

[txab]

3 hours ago, Supreme Pizza said:

"rear end feel like it loads up and unloads"

 

I'm not sure exactly what you mean.

 

Can you describe the problem in a different way?

In the 900 series people described like being rear ended by someone, very light lurch

[richard wysong]

1 hour ago, txab said:

In the 900 series people described like being rear ended by someone, very light lurch

yeah check the brakes, parking brake shoe delamination is common but I don't think it would cause your symptoms. make sure the caliper slide pins aren't frozen

[Chebbyfan]

With disc brakes, where does the drag come from?  There is almost no drag at all on the rears when I jack it up and turn the wheels.  Do I need to adjust the emergency brakes for the drag? 

[richard wysong]

if the parking brake works don't worry about it, if it doesn't stop the truck from moving in gear there is a star adjuster on each wheel but you will probably want to remove the rotors and clean and check the shoes and lube the adjuster. no drag is good

[richard wysong]

if you have to replace the shoes it may be easier to pull the axles to get the hold down springs on and off, if the backing plates have seen better days change them, they make 2 piece 1s if you don't pull the axles

[dna9656]

Sound to me like you're talking about a brake issue more so than an axle wrap issue but I don't know very much about axle wrap but like all old guys I got a story for you...

I had a '67 GTX with a 383 magnum and a AFB (cool huh?) and a 426 4 speed iron cased tranny. One day the rear brakes stuck on then broke loose. The seals in the ends of the axle tube had worn out and gear lube had contaminated the brake shoes, I thought oil would make them slip, nope oil makes them GRAB. I pulled the axles out and found "shims" on the axle bearings (there was no roller or ball bearing in there just a bearing. The last guy took a coke can and cut strips to fit in the bearing instead of spending the $ to do it right.

[Supreme Pizza]

A coke can? That's crazy man. Why use a coke can, when there are so many perfectly good beer cans around.

 

 

 

 

Edited December 19, 2021 by Supreme Pizza