so i'm still feeling out all the quirks and tendencies of the '04 CCLB i just picked up, and one thing thats bothering me is a "clunk" for lack of a better verb.

when i press the accelerator and the RPMs come up while in forward gear, right after the truck starts to move i feel a clunk in the driveline. truck drives and shifts fine, but as i slow down i get the same clunk right before i come to a complete stop. i checked the driveshaft u-joints and carrier bearing with the trans in neutral and all seem tight via my low-tech inspection..

something in the trans? i read through the 8-page torqshift tech thread and didn't see anything pertinant in there. i'd like to nip this in the butt before it propogates to something detrimental.

 

Common clunk problem is the drive shaft slip joint. Split the drive shaft and grease the slip joint splines. I use blue marine grease. It has fibers to hold it together and is water resistant. Mark the two shafts so they go back together in the same orientation.

 

Have you tried greasing the slip joint of the drive shaft? I know it can cause a clunk if dry

 

i'll look into it.

the clunk feels like it is something with more mass behind it, but dampened.. doesnt have a metal-on-metal harshness by any means. i hoped for a driveshaft diagnosis, but i almost wonder if it isnt stall-related.

 

Has the tranny been serviced according to the book with only Mercon SP or LV fluid?

 

ha, great question... i bought this truck on what i would consider "impulsive" terms; it all happened so fast and i didn't do all the homework i normally would before buying (anything)... which grinds me.

i've been around here for a few years and drove a gasser superduty the past 5 years, so i'm not bright green when it comes to the platform, but this drivetrain is new to me.

i'm guessing a service was done very recently; a check of the fluid level revealed a very clean looking and smelling acceptable level. not sure whats in it though.

 

well a google search turned this up, which sounds right in line with my observations:

http://www.fordforum.com/forum/ford-...ing-off-13198/

 

Whenever I buy a used vehicle if they don't have all of the up to date service records I bite the bullit and change all fluids and filters. That way I have a starting point on everything. Only use OEM filters and recommended fluids in the 6.0 and torqueshift.

 

https://www.ford-trucks.com/forums/1...ard-clunk.html