So I have a 2004 F-150 Crew, 5.4 Fx4, short bed, with 121,392 miles on it. The original tranny was replaced at 74,658 because it wasn't building the right pressures to engage reverser, drive and other gears. After roughly 46,000 on the new tranny and one round of fluid change on it, I'm having a coasting reaccelerating bump in the transmission. For example, if i was to make a moderately slower speed turn. I would take me foot off the gas, let the truck coast, make my turn and while leaving the turn come back on the gas I get a clunk. It never slips, its just a hard luck up back into gear, more pronounced at slower speeds. The only thing I can think of is that the
one-way-clutch in tranny is to sloppy, and it doesn't reales at the right RPM's.

The truck runs through all its gears on a normal or hard acceleration smoothly. It just has this clunk coming off coasting at slower speeds.

Any suggestion on what my problems is or
way to fix would be much appreciated

 

Have you talked to the place that replaced your transmission? Not too many transmission technitions on this forum. A problem like this is going to require professional advice.

 

Maybe its just slack in your u joints. Its worth the time to check them.

 

The tranny was replaced by ford. I pretty sure that it's not the u-joint because when I clime under the truck a see if there is any play in the driveshaft there's no movement when I try and twist it.

I guess i'll just have to take it back to dealer.

Any one know what the warranty would be on a tranny replacement?

 

Mine does the same thing. I'm guessing torque converter. But I'm leaving it alone.

 

I had a similar issue. I replaced the U-joints and greased the slip yoke; it was bone-dry. I used blue marine grease for the slip yoke instead of the expensive ford blue stuff.

I don't think the u-joints were bad, I just went ahead and did it while the drive shaft was off.

There was a TSB involving this that lead me to the slip yoke.

 

Definitely could be your slip yoke, it sucks! I hate them. Lots of forums open with the slip yoke issue.

 

Here's the TSB(s) related;

TSB
05-26-11 DRIVESHAFT SLIP-BUMP ON DECELERATION OR ACCELERATION FROM A STOP

Publication Date: December 21, 2005

FORD: 2004-2005 F-150
LINCOLN: 2006 Mark LT


ISSUE:
Some 4x4 2004-2005 F-150 (excluding Heritage) and 2006 Lincoln Mark LT vehicles build prior to 7/1/2005 may exhibit a rear driveshaft slip-bump concern on deceleration or acceleration from stops.

ACTION:
This condition can be attributable to the slip yoke of the rear driveshaft having not been lubed when the vehicle was built or wear/flaking of the spline nickel coating. Refer to the Service Procedure.

SERVICE PROCEDURE

Remove the rear driveshaft per Workshop Manual Section 205-01. Be sure to index-mark the driveshaft during removal to maintain alignment during reinstallation.
Inspect the rear driveshaft slip yoke for the presence of grease. If no grease is present proceed to step "a" If grease is present proceed to step "b".
If the splines of the slip yoke are dry, but do not show any signs of wear, nickel coating flaking, or contamination, then apply 8 mL (0.27 oz.) of the new slip yoke grease, distributing it evenly around the bore. If flaking is found, then REPLACE the rear driveshaft.
NOTE: EACH SYRINGE CONTAINS ENOUGH GREASE FOR 1 SLIP YOKE, THE PART NUMBER IS FOR ONE APPLICATION.



If grease is present, inspect the driveshaft for signs of nickel coating flaking. Flaking can be found by inserting a clean rag into the yoke, wiping the spline surface and then looking for nickel "glitter". If flaking is found, then REPLACE the driveshaft.
NOTE: FLAKING/GLITTER WILL BE VERY SMALL PARTICLES IN THE GREASE ON THE RAG



Re-index and install the driveshaft per Workshop Manual.

PART NUMBER PART NAME
5L3Z-19A506-A Slip Yoke Grease

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http://www.thedieselstop.com/faq/949...les/042606.pdf
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and a related thread;
http://www.f150online.com/forums/200...oke-clunk.html

 

Correct me if I'm wrong, because I not an expert on driveline components. Are not slip yokes lubed by transmission or transfer case fluids? So this TSB is for trucks with two peace drive shafts?

Is removing a signal shaft drive shaft and yoke from a 4x4 a do at home in drive way activity? Would anyone know the torque specs for the four blots connecting the drive shaft to the rear end?

 

I have the 2wd; but the TSB referenced the 4x4 as well. I have a two piece drive shaft, the slip yoke is the one sitting right next to the carrier bearing. It is not lubed by any fluids at all, some (braver than I) people with this issue are machining-in grease fittings for an easier time regreasing it in the future. If you DON'T have the 2-piece driveline, then this won't apply - and yes the yoke into the transmission would then be lubed by the trans fluid.