Truck experiencing a "shudder" when slowing down

[AHill100]

My truck is getting a shudder when slowing down, right at around 5mph. It only happens when slowing, not when accelerating, and only at very low speed as I coming to a stop. It feels like it is coming from the drive train, not the suspension. It happens with the engine on, and I can recreate it with the engine off and coasting to a stop.

Sometimes at normal speeds, when I have a very light to no throttle I will feel a light vibration, which feels like it is coming from the drive train.

Has anyone experienced this, any ideas?

Thanks,

 

[Mark31]

Warped rotors?

 

[AHill100]

Warped rotors?

Will do it without the brakes and only at about 5mph

 

[NIsaacs]

I would check your U-joints.

 

[AHill100]

It started when I experienced what seemed to be an injector problem, white smoke on startup, rough running off idle and seemed down on power. The tank is was low and I had treated the tank, when full, with Redline diesel treatment, a big dose to “clean” the injectors. It had been running fine for 400 miles burning down the tank.

I added diesel to 3/4 tank and the smoking cleared up and it ran better but still not perfect. After another tank it is now running good.

I would think maybe injector misfire at that specific speed with no throttle.

But it does it with engine off coasting in neutral and does with and without the brakes.

I would check your U-joints.

 

[SnoKing]

Dry U-joint or stub axle joint?

 

[AHill100]

Dry U-joint or stub axle joint?

Maybe the front drive shaft grease able u joint?

 

[Mark31]

Warped rotors?

I wanna change my vote. (I had a hanging chad!) I vote wid the Nickster, so if it is wrong, I can blame it on him! Take a little 5 mile scenie cruise around the 'hood, then pull up on a pair or 4 of 2x6s (depending on yo age and circumference) and zap 'em wid yo IR gun. If a joint is going bad, it is building heat. You don't have an IR gun? Shame!! If anybody hauls or tows, they NEED one. My wife is hoot owl sick and I just took her temp with mine. Just cover her eyes and shoot the carotid arteries on the side of her neck. It will run within a couple of tenths of a thermometer!

 

[S.Morris]

Middle ujoint on rear dshaft

 

[AHill100]

Thanks everyone for your help. I’m going to go through the driveshafts & u-joints and carrier bearing next as you all suggested. I like the idea of the IR thermometer, been wanting one of those anyway.

 

[Motorhead]

I have a Raytek IR temperature gun. I have the second one on this page and have had it for over 10 years. https://www.raytek-direct.com/stores/raytek-mt-series-portable-ir-thermometers
I also would suspect the driveline u-joints. Some guys pull the FRONT drive shaft to see if the issue goes away. If it does then check the cardan joint on the front drive shaft.

 

[basfire]

Happened to me. Same vibration. You cannot check the 'U' joints with the drive shaft installed. They all seemed tight. Once I removed rear drive shaft the rear 'U' joint had significant play. I replaced all 'U' joints on the rear driveshaft.
Problem solved

 

[Missouri Mule]

If your front brake pads been on for a while check them out. Take a look at the rotors also.

 

[AHill100]

I want to thank all you guys for the great replies and ideas. I have removed the rear driveshaft and tomorrow it goes into the drive line service for new U joints, carrier bearing and balancing. None of the U joints feel loose to my hand. I'm also going to replace the transfer case extension dust boot and seal which covers the drive shaft yoke that slides in the end of the case. I'll let you guys know if this fixes it.

 

[AHill100]

Service Manual says to use the special 9037 output shaft seal installer tool. I can buy this on eBay for $25, Miller brand. Or I can do the PVC pipe technique and a block of wood to tap the seal into place. Any advise on this? I don't mine spending the $25 if it will make a difference...