I have an '04 F150 super cab, 5.4L V8, 4WD, FX4, Tow Package, K&N air intake, Flowmaster exhaust. I tow a 20' enclosed trailer (about 4k lbs loaded) about 2,000 miles/year.

I have a pretty good fundamental understanding of engines and transmissions but am not a mechanic. I get my oil changed every 3,000 miles and have had my 30k and 60k service done at a Ford dealership. The truck has 74k miles on it now. Earlier this year I lucked into a cheap small car to use as a commuter so I now only use the F150 for towing but it used to be my daily driver.

I have been reading some forums about towing and transmissions and I'm starting to worry. It seems to shift fine. I think I might have felt a slip a few months ago but not sure? A couple of questions:

1. Ever since I've owened the truck, I get a rare problem when it down shifts. I'll be coasting from 40 or 45 mph to 20 or 30mph and probably was in third. Then when I hit the gas lightly to speed up, it "clunks" down to second (I think it's second). This happens maybe once every month or two. any thoughts?

2. From what I've been reading on this forum, my trans is getting old. What can I do besides the Ford recommended service to make sure my tranny isn't going to go out in the middle of a trip with my trailer?

3. Should I get a trans temp guage? If so, anyone have a ball park cost for parts and labor?

 

It might be in the middle of a shift when you press the pedal, changing the torque going into the trans during a shift. The trans doesn't handle a change like that real elegently. That makes a clunk.

Keeping up with the maintenance is the best thing you can do. The next best thing is to make sure you don't overheat it by installing a trans temp gauge.

 

most '04s have updated calibrations available. There's various issues that they've changed with the new calibration. If a Ford TSB applies, and your vehicle is covered under warranty, you can get the update for free. Otherwise, might be worthwhile to ask your local dealer how much they'd charge to update your PCM.

 

Sounds like the ole' typical "Driveline Clunk". I've had this in all the trucks I've owned, though less with my 05' F150. Always was told by the service guys and local shops it has something to do with the slip yoke b/n the tranny and the drive shaft. It can be greased and might help for a while. I wouldn't worry about it unless the tranny's not shifting correctly. If the tranny downshifts right and shifts good, I wouldn't get all worked up. I spent too many hours and labor trying to hunt down and cure this with my Z71. Rear wheel drive vehicles esp trucks are going to have a little slop esp as the truck gets older. It is anoying to hear but given the clearances/tolerances b/n the tranny, driveshaft and differential, esp as the truck ages, a little clunking won't make me go wanting to FIX something. Just some food for thought.

 

Thanks for all the info

 

you saying that this clunk is normal? My dad's f150 99 4x2 4.6 does that just about all the time now, it feel like the damn tranny is going to fall out of it

 

Yup, that clunk happens on a lot of these transmissions. I woulnd't call it normal, but I wouldn't call it a problem that needs attention either. It's just a clearance issue and a transmission that does it will likely last just as long as one that doesn't do it.

Darrin