I don't know if this will help or if it applies to auto tranny's but I had a 96 351W 5Spd. 4x4 that clunked when starting off and it was a pain the stealership replaced the slip joint and I did the u-joints with no help. I talked to a friend who knows his FORDS and he told me the connection between the tranny and the transfer case is a dry connection and the clunk you hear is the two shafts climbing off of each other because there is no lube left on the shafts I wasn't sure I believed him so we pulled my transfer case back and he was right the two shafts had rust on them and the slpines were all clogged up with rust we wire brushed the shafts and put some good lube on put it back in and I never had the clunk again.
Good luck
Glen
05 F-350 4x4 Reg Cab PSD 6Spd. (No clunk yet)

 

This is a GREAT thread! I've noticed a slight "clunk" on acceleration. Now I have some idea's on what to check for...since buying my Used 2003 F250 SD SC SWB XLT V10 Auto 4x4...I have been busy... getting it ready for winter.

biz

 

Well biz, it's just getting better. Here is what you want to use to lube the splines.

 

Diesel --

Thanks my friend! That is a GREAT picture of the grease.

Thanks again,
biz