I tried finding a post like this but have not able to find one so i apologize if i missed it. My 00 dakota has been having this vibration sensation for awhile now but recently i have noticed it is starting to become worse at times. It happpens off and on around 30- 40 mph and then starts to smooth out. you can really feel it bad when going in reverse with the brakes half applied like when pulling out of a parking spot and the vibrations are definitely from the rear. a few years ago i did have some on the u-joints replaced on the rear driveshaft but i dont know if they went bad or the others finally went bad! rear differential bearing was replaced, and i did have problems with the rear brake shoes not adjusting correctly by my own human error. i do at times makes sure my tires are balanced when i have them rotated, but that has not ever seem to clear the problem.

Any Ideas? im leaning to having u-joints looked at and possibly having the driveshaft balanced.

 

U-joints would be one of the first things to check. If you have the two-piece driveshaft then you have 3 u-joints. It is best to replace them all at the same time. Use Spicer u-joints. Spicer is the best quality and is OEM too. Your truck came from the factory with Spicer u-joints. If you have a lot of miles on the truck, it is also a good idea to replace the carrier bearing as long as the driveshaft is out of the truck anyway. A good driveline shop can take care of it for you and balance the driveshaft if needed. U-joints can be done DIY, I tried it myself and almost got it right but wound up having a shop replace all 3 u-joints with Spicers, they replaced the carrier bearing and balanced the driveshaft too. I saved some money by R&R'ing the driveshaft myself but the whole job still only cost me about $250.00 if I remember it correctly. It was money very well spent.

If you have a 4 wheel drive truck the vibration could be from the transfer case or front driveshaft. I know nothing about 4 wheel drive myself. Maybe you could disconnect the front driveshaft, drive the truck and see if the vibration goes away. I am no expert by any means would guess though if the vibration is felt more towards the rear of the cab or in your seat the problem is in the rear driveshaft.

Jimmy

 

Do you have a manual trans or auto if manual it could be the clutch is ready for replacement.

 

i already have replaced the tranny with a brand new one due to keeping this truck for awhile yet last month and i had to replace the H- yoke and the front driveshaft and was still doing it without the front shaft.

 

Ok manual trans or auto?

 

it is automatic

 

the other thing i starting to notice is when i am just starting to coast from a stop position, you can start feeling the rear shaking or vibrating.

 

Have you pulled the Diff cover and checked that out also grab the yoke that goes into the diff and feel if it has any movement any movement should be noticeable in the driveshaft from one end to the other. If you replaced any U-joints you may have a cup off or just not lined up perfect any amount off how small can cause vibration.

 

if i take off the cover and notice metal shavings in the fluid what should suspect?

 

There shouldn't be metal shavings. That'd be gears or bearings. Take a close look at the spider and ring/pinion gears for damage.

You might see pieces of metal, from broken clutch pack retaining clips - if you have the trac-lok (LSD). They can/do fail.