I just picked up this truck last week and had my first chance to really use the 4-wheel drive today. While in 4lo, there is slow "thumping" sound..... the sound is twice as fast when is 4hi and not there when is 2 wheel drive (with hubs locked) Since the front drive shaft will spin with the hubs locked, it seems like it might be a u joint because it would be under load while in 4 wheel drive and just spinning with the t case in 2wd. Any thoughts?

 

could be a Ujoint, have you checked the front shaft for excessive play?

 

Yeah, it did seem to have quite a bit of play.

 

Check the ball looking joint in the front shaft ( called the double carden joint) I had one go in a 81 pick up. It still worked in 2 wheel but sounded dangerous in 4 wheel. <B>

 

While under the truck, will there be any visual clues if it's bad or not? What should I look for.

 

The front driveshaft will have a knuckle close to the transfercase , you'll see a little ball like thing inside a housing push it up and down and see if it's broken. Its just after ujoint closest to the case. It may be cheaper to find a front shaft.
hope I helped! <B>

 

I had this exact same noise on my 84 at one time. When the hubs were locked and in 2wd....no noise. When in 4wd hi/lo with the hubs unlocked....no noise. With the hubs locked and in 4wd......it sounded like a box of rocks. I rebuilt the the front drive shaft and the noise went away.

 

I'm curious; it looks like you did the rebuild yourself…. a friend of mine told me the cardan joint is a bear to work on. Did you run into any trouble with it? Also, how much did the rebuild cost?

 

I have a friend with a machine shop.......

The double cardan is more tricky but do-able with patience. A shop will likely charge a hundred bucks depending on the condition of the slip spline etc.

It made a world of difference. Funny thing is, that the bad u-joints did not demonstrate their condition until after I installed the lift. It makes sense now, but at first, did not get the relationship.

 

So What was the verdict? Ujoint or Carden?

 

The jury is still out. I have the truck parked out at a friend's farm. It's either been too cold or too wet to wrench on it for the last couple of weeks. I did however call a drivetrain shop and he quoted me anywhere from $200-300 to rebuild the driveshaft. This seems a little high, no?

 

Check on a custom one, or I have a used one from my 83 I'll sell for 50 bucks plus shipping.

 

Here's a pic

 

How difficult are they to work on? I'm not a master mechanic but I do know the end of a screwdriver. I checked the prices of parts (u joint/cardan) at Scmucks and are lower than expected.

 

rebuild linky

 

Last time I worked on mine I stuffed a dirty screwdriver threw my finger! Thank god for tetnus shots!

 

Does anybody know where i can get the replacement balls for these on a 82
Thanks Csob

 

mine has a similar noise, more of a clunking sound. sounds like i will be rebuilding the front shaft soon.

Al