Drivetrain shaking and rumbling when coming to a stop

[lumbee1]

I've had an increasing issue of the drivetrain shaking when I come to a stop. Whether I hit the brakes or not, as the Cruiser come to a stop I get a deep shaking and rumble from the driveline. It does it just about everytime and is most noticable around 1400 to 1000 rpm. Sitting at idle I get what I think are the typical Cruiser shaking. The driveline doesn't seem to shake or not as bad on acceleration. Straight line driving all the way to 75mph is fine.

This problem became noticeable months ago but here some relevant work that I've done recently.
- 1 month ago axle regear. 3rds were shipped off to ECGS. While the 3rds were out, I did a full axle rebuild. Wheel bearings torqued to 25ft/lbs. No change is shaking before and after.
- 1 month ago replaced front driveshaft. I actually drove it without a front driveshaft for 50 miles. No change.
- 1 yr ago eplaced rear driveshaft U-joints. Both u-joints were replaced to fix a squeak, but this was some time ago and I don't remember if or how bad the shake was then.
- New calipers on the front, 1yr old calipers on the rear. Rotors are 1yr old
- Springs and shocks. Both springs and shocks are farily new and in great shape.
- Transfer case fluid was swapped 10k miles ago.

Suspects:
Rear TC output bearing. I don't know what a bad bearing feels like for the TC. I do not have any leaks from the TC and I've read the seal and bearing go around the same itme.
Motor mounts going bad. I guess that's a possiblity but these rarely fail and I would notice this during acceleration not decelereation.
Exhaust hangers? I've got one to take a look at these.

To elminate the rear output bearing, I am going to pull the rear driveshaft and drive without it. Hopefully there will be a huge difference and I can start fixing it.

 

[nukegoat]

Pinion bearings should be looked at

 

[Tools R Us]

Front caliper bolts tight, IIRC, 90ft/lb.

 

[lumbee1]

Front caliper bolts tight, IIRC, 90ft/lb.

Brakes were done with the axle regear. I go by gud-n-tite for all the caliper bolts and I check them regularly.
Lug nuts torqued to 90ft.
Steering was completely revamped a few months ago and alignment is in spec and caster is -3*.

BTW, the shaking has gotten gradually worse to the point that the truck is rattling when coming to a stop. I've also got to figure out what exactly is rattling.

 

[lumbee1]

Pinion bearings should be looked at

The driveline shake and rumble was present before the regear and hasn't changed. Solid spacers were installed instead of crush washers.

 

[baldilocks]

Does this happen as soon as you lift your foot from the gas pedal at any speed? Speed dependent? How long will it go on for?

 

[excessive]

Put a jack under your motor and trans mounts , test them ... they could be bad .

 

[lumbee1]

Does this happen as soon as you lift your foot from the gas pedal at any speed? Speed dependent? How long will it go on for?

No. I can coast at any speed and it doesn't happen. It's only when slowing down or coming to a stop. I don't think a video would capture the sound and feel of the rumble.

The best way to describe this is if I had sand rail tires on the truck. At speed they are somewhat smooth but as the vehicle slows down the gaps between the paddles become more noticeable. And causes the shaking.

 

[Michael Hanson]

Hi, Check rear drums. Mike

 

[blkprj80]

Maybe swap your tires from side to side and see if it changes anything?
My friend's 80 shook and rumbled coming to a stop due to his tires.

 

[nukegoat]

Driveshaft angles

 

[KSJ85]

What tires are you running and how old are they. Badly cupped?

 

[alia176]

Maybe rotate the tires to see if the vibes follow?

Secondly, perhaps take the front end out of the equation by removing the front DS and the drive plates. But, a sand paddle like sensation is a rather pronounce type of vibe that I don't think would come from a gear meshing area or a Tcase bearing area. However, the front wheel bearing *could* be suspect if they're badly indented some how. Still, this is a WAG at this point!

 

[mudgudgeon]

go by gud-n-tite for all the caliper bolts

Gudentite is a fickle mistress. When you least expect it she'll bend you over and peg you gudenhard!

Plenty of thread on mud about lost caliper bolts, I've lost one, and now torque then every time.


How are wheel bearings? Preload good?

Are wheels all seated / centered properly on the hubs?

 

[alia176]

Brakes were done with the axle regear. I go by gud-n-tite for all the caliper bolts and I check them regularly.
Lug nuts torqued to 90ft.

The lug nuts are usually torqued at 76 ft-lb just a FYI Since someone is already picking on you, figured I'd jump on.

 

[Cruzerman]

Since this doesn't happen while coasting, I would be thinking brakes.

 

[lumbee1]

Since this doesn't happen while coasting, I would be thinking brakes.

With brakes not applied, it still rumbles and shakes coasting to a stop.

 

[lumbee1]

The lug nuts are usually torqued at 76 ft-lb just a FYI Since someone is already picking on you, figured I'd jump on.

I torqued my lug nuts to 85ft/lbs.

 

[lumbee1]

Gudentite is a fickle mistress. When you least expect it she'll bend you over and peg you gudenhard!

Plenty of thread on mud about lost caliper bolts, I've lost one, and now torque then every time.


How are wheel bearings? Preload good?

Are wheels all seated / centered properly on the hubs?

I did the axle job on both the front and the rear. The shake was there before the regear and after the regear. Nothing changed.

The bearing preload was a mess before I did it. The fronts were too tight and the rears were too loose. All 4 hubs were done with the @Tools R Us method and torqued to 25ft/lbs. The preload is perfect and the hubs are barely above ambient after hundreds of miles.

 

[lumbee1]

Maybe rotate the tires to see if the vibes follow?

Secondly, perhaps take the front end out of the equation by removing the front DS and the drive plates. But, a sand paddle like sensation is a rather pronounce type of vibe that I don't think would come from a gear meshing area or a Tcase bearing area. However, the front wheel bearing *could* be suspect if they're badly indented some how. Still, this is a WAG at this point!

Done. It changed but wasn't a drastic change. I also suspect the tires. I have even "looking" wear but I've dealt with out of round and unbalanced tires before on previous vehicles.