Ok, I got a 03 F150 with a 5.4 going to a 4R70W with a BW4406 Electric Transfercase then to a 9.75" rear end. After accelerating from a dead stop only the trans getting ready to shift into second there is a clank comming from that area. It had done it for a while then after some off roading it went away (see driving in 4lo for about 60 miles). This clank of sorts only happens when shift low in the RPM range definatly hear it shift at 1800 to 2000 rpm. It sounds like it's just before the shift or right at it. If it was my guess I'd say solinoid going bad but who knows. I used to have a delayed engagment in the AM but that has gone away. However I got a weird shudder rollin on the throttle at 45 mph in 4th gear conveter locked the otherday. Also with overdrive on and slowing from the mid 50 mph range and hitting the gas (not hard at 20 to 28 mph the engine revs then slams into gear. I have flushed the fluid 3 times now in 10K miles and get a good bit of clutch material each time (a bit less on the 2nd and even less on the 3rd). Any help would be great since I only know counter shaft trannys.

 

broken accumulator spring?

 

could be, how do you check? Is removing the valve body hard?

 

No need to remove the valvebody. The 1-2 accumulator is out in the open you just need snap ring pliers and a strong thumb.
Alan

 

any ideas where to look?

 

Remove the pan, drivers side front of the transmission. You will see a hole with a snap ring covering the accumulator cap. Push the cap up with your thumb and remove the snap ring. The spring will force it out, if it is broken it may not then you just smack it lightly with a small hammer or a screwdriver handle. It'll pop out.
Alan

 

Hey did u ever get that fixed? I hear the same noise everyonce in a while when i takeoff from a dead stop uphill. It sounds like a clunk right under the hood. I havnt heard it recently though. Besides that it runs flawlessly. I only have 14000 miles on it.-Mike