Need Sanity Check! Clunking while driving solved by removing front driveshaft

[goathearder]

FIXED - See Post #13

Ok, so anytime my Blazer is in gear and driving over 3-4mph I would get this very loud clunking and heavy vibration I could feel through the t-case shifter. Would get less noticible at speed but definitely still there. Sounded like it was coming from between the t-case and front passenger tire so naturally I assumed the driveshaft would have something to do with it.

As a point of reference, it would do this in ANY setting of the driveshaft. So I took the driveshaft out, drove around in High Loc and wala, the clunking is gone. Check the driveshaft and there are no wear marks so I don't think its hitting anything. Obviously I am thinking the u-joints are shot BUT I only bought the truck a month ago and the PO said he changed the u-joints recently. Now it very probably he did them wrong or not at all or that the just failed but before I throw some u-joints at it, I need a sanity check to make sure I am not missing anything simple. I don't know a ton about u-joints and they look ok to me but I probably wouldn't recognize if they were bad.

What else could be wrong?
Would bad u-joints make that clunking sound?
Could the yoke on the ring gear or t-case output have play? Would that cause a clunking sound?

Anything stupid I am missing?

Thanks in advance for any advice,
John

 

[K85 Octane]

203 T case right
are you still full time?
lockable hubs or slugs in front axle?

if you can't physically move the joints around with your hand, they are probably not bad enough to cause a clunking sound. If vibration at speed was a problem, I'd say maybe, but to have problems at 4mph, ugg.

Less noticeable at speed uh....

 

[jbz400]

if the u joints are good i would check the center pivot point. alot of times the male end will break off. its inside the cv you will most likly have to take it apart to see. keep us updated

 

[goathearder]

203 T case right
are you still full time?
lockable hubs or slugs in front axle?

if you can't physically move the joints around with your hand, they are probably not bad enough to cause a clunking sound. If vibration at speed was a problem, I'd say maybe, but to have problems at 4mph, ugg.

Less noticeable at speed uh....

Yea, 203. I am still full time on it and no switches on the hubs so I am assuming there are slugs in there. I will check for any play in the yokes tonight and hope I don't have any.

And yea, definetely less noticible at speed, does that point more to u-joints???

Luckily U-joints are only like 40 bucks total so I guess it doesn't hurt anything to swap some new ones in.

 

[goathearder]

Bless the internet. Read a bunch of articles on how to do the u-joints and the double carden so I just ordered the u-joints and a new centering yoke. Hopefully that will fix the issue and even if it doesn't I know my driveshaft is good to go for a couple years, hahahahaha.

 

[K85 Octane]

the double joint on my s10 cost me big bucks to replace. I sh1tcanned the driveshaft and went with a standard u joint. Stupid designed squeaking bastard, not needed on low vehicles fuking GM!!!!

keep us updated

 

[fouronereason]

I had clunking in mine, under different situations tho, I jacked my front end up turn some tires back and forth and found out I sheared some teeth of the spider gears. Might wanna try jacking it up and seeing what you hear.

 

[goathearder]

Yea, I tried jacking it up and I couldn't spin the tires fast enough to hear the clunking. I was hoping that would be an easy way to find the issue.

 

[andyblack]

Maybe your front driveshaft was dented or out of balance?

 

[GMC Truck]

My 83 had that same problem is it was the splines worn out in the slipyoke. Cost a ton to fix so just replace if its shot. To check your splines you MUST loosen the spline seal collar then you can feel the loosenes. Some driveshafts have "coated" splines and the coating gets worn off.

 

[goathearder]

Hmmmmmmmm interesting. So the splines are somewhere near the connection of the two parts of the ds? What looseness would I be feeling for? Rotational or linear looseness?

 

[GMC Truck]

Loosen that slip collar (unscrews) at the splines and check to see it the splines wobble. Try sliding them in and out and check for wobble at various points. They mostly get worn at there normal running location so as you slide it out they will tighten up. I was also told that only the "course" splines are coated not the fine splines.

 

[goathearder]

Well I am happy to report the driveshaft rebuild was a 100% success!!! The center bearing or whatever you call it in the double carden was THRASHED. Totally dry and had chunks broken off all over the place. Put a new one of those in and all new u-joints and there is absolutely no clunking anymore.

 

[jbz400]

good to hear