Tonight on my way home, my truck stated making a really strange heavy clunk. It seems to happen more when starting to move. There is a large shake of the entire vehicle as if a cog or gear in the drivetrain was skipping a tooth and then continuing. I was able to get it home, but I'm concerned about even taking it to my mechanic since I don't know how long until it stops moving entirely.


2003 Dakota, 4x4, manual transmission.

Engine was rebuilt 18-24 months ago, and a new clutch was installed at that time.


Any ideas?

 

Could be a bad u-joint.

Does it do it in every gear? How about neutral?

 

It has happened in reverse and first.

I don't know about neutral, but it sounded like it was coming from the rear drivetrain.

I'm midway through replacing the universal joints (I have the rear driveshaft on the floor of the garage, and I'm working on the front one). I have new u joints with grease nipples that I'm going to install.

There are some things I noticed while I was under there that concern me (or maybe I'm imagining problems).
A) I think it feels like the rear shaft is skipping inside the transfer case.
B) the play in the front diff doesn't feel right. There is the usual play and then a little more play where it seems to be scraping.

*crossing my fingers that it's all ujoints*

 

How are the motor and transmission mounts too?

 

Quick look says the transmission mount is ok, but I'll investigate it and the engine mounts after this job is done
(good advice, thanks)

 

You can always pull the front diff cover and give it a look, same with the rear. Maybe you have some metal. You could also pull the plug on the transfer case and check it too.

I'm thinking front driveshaft. It seems to be a common problem.

 

New paranoid observations:
(note: rear driveshaft is totally removed, and front u joint/spline assembly is on the workbench)

Rear left wheel spins without moving either the right wheel or the differential flange. The skipping that I noted in a) above is actually at the rear diff, and if I spin the flange the right rear wheel turns, but sometimes I feel it skip (kind of like when on a bicycle the chain skips a tooth)


[thank you very much for your advice and guidance]

Now to swap these u joints out

 

When you say "front axle" are you telling me that after I remove the 6 small bolts that hold the front axle to the transfer case, I'm not going to find a replaceable u joint in there?

 

Ok, so I took the 6 bolts off the rear (transfer case end) of the front drive shaft.

How the heck do I get the front axle off?

I don't mind applying elbow grease or encouraging it with a hammer, but I want to make sure I'm pushing or whacking at the right part.

There seem to be four layers of different pieces back there.
(from front to back)
-Three curved pieces that distribute the pressure from the bolts (these are off and sitting with the bolts)
-A thin galvanised looking piece of metal (that is sort of the end of the rubber boot)
-A rusty steel donut (that the bolts slid through)
-A funnel shaped piece of rusted steel that has the threads for the six bolts in it

I'm not sure which part I should be pushing around.

 

Not sure on an '03. On my '00 it's bolted to the front differential as well.

Pull the entire front shaft out of the vehicle.

You may want to just replace it. It has a CV joint on it and it's known to fail.

The clunk in the rear, pull off the differential cover and take a look at the ring and pinion. If you have an LSD, they are known to break clutch pack retainers and they can go through the gears.

Neither wheel should spin without the opposite wheel OR the flange moving.