Lurching while coasting (2 Viewers)

[ICY80]

Wanted to hop on here and see if anyone knew what could be going on with my 80. At approx 55 miles an hour while maintaining speed or coasting I feel a pretty violent lurch. Feels like it could be driveline related. My 80 is lifted 3 inches, no caster correction, but does have a front dc drive shaft. And another thing that just crossed my mind is the slop in the driveline when I let off or accelerate. Possibly Just a uv joint? I know I gave limited information but that’s about all I have. Thanks guys.

 

[BILT4ME]

Wanted to hop on here and see if anyone knew what could be going on with my 80. At approx 55 miles an hour while maintaining speed or coasting I feel a pretty violent lurch. Feels like it could be driveline related. My 80 is lifted 3 inches, no caster correction, but does have a front dc drive shaft. And another thing that just crossed my mind is the slop in the driveline when I let off or accelerate. Possibly Just a uv joint? I know I gave limited information but that’s about all I have. Thanks guys.

I'm going to reply here instead of on PM in order to keep the benefits for others out in the open in case someone else is searching for a similar issue.

What year is your truck?
How many miles (approx) are on the truck?
What recent services have you done (in the last 25K minimum)?

Does the lurch feel like something is binding?
Is there a noise associated with the lurch?
Is your rear driveshaft properly in phase with itself?
Are your U-Joints in good shape?
Does the noise / lurch change after you grease the U-Joints and slip yoke?
Is the lurch repeatable under controlled conditions?
Are your front wheel bearings loose? Properly adjusted at 35 LB Ft / 45 LB-FT?
Which direction do you have your DC front DS installed? Which end is the slip yoke?
Have you done any front axle alignment to properly position your DC shaft?
Have your suspension bushings been replaced with OEM? Anything else?
Have you changed all your fluids or at least checked them to make sure there is no debris or stripper glitter in the oils?
Are your pinions loose? (Does the shaft move in and out with rotation?)

There are LOTS of possible issues here from misaligned driveshafts to loose wheel bearings to bad bearings in the transfer case.

If you don't know how to check this stuff, say so so we can flame you,............................................... I mean help you.

 

[mudgudgeon]

slop in the driveline when I let off or accelerate

Most likely worn out splines in the birfield/CV axle and drive flange connection at the front hubs. If so, both parts will be worn

 

[ICY80]

SWEET. Thanks for the info. Truck is a '97 model. I'll have to check it out more in-depth this evening with the info you guys gave me. I chocked the tires, threw it in neutral, and checked for slop in the drivelines. It does have some play when you spin, but none up and down or side to side. 247k miles everything is probably factory. I always keep it greased and fresh oil in the diffs/transfer case. Lurch continues to happen repetitively under the same working conditions. Does have new wheel bearings. Haven't adjusted the axles.

 

[BILT4ME]

SWEET. Thanks for the info. Truck is a '97 model. I'll have to check it out more in-depth this evening with the info you guys gave me. I chocked the tires, threw it in neutral, and checked for slop in the drivelines. It does have some play when you spin, but none up and down or side to side. 247k miles everything is probably factory. I always keep it greased and fresh oil in the diffs/transfer case. Lurch continues to happen repetitively under the same working conditions. Does have new wheel bearings. Haven't adjusted the axles.

How about a few pics from the sides of the drive shafts both up close and far away enough to see relationships of parts.
Maybe a video or two of the lurching and noises.