I'm new here, and not too experienced with drivetrains so bear with me. This and the other F150 forums have helped me with a lot of small fixes. I have done lots of searches on this issue as it seems to be common, but each case seems to be slightly different and I could use some insight.

2002 F150 KR 5.4 with 126K miles, no real previous issues (front rotors all that comes to mind).

1) For several years now my truck has shuddered a little if I accelerate a certain way out of first gear. This is amplified when I'm making a turn from a stop. The other gears shift just fine IMO.
For a shorter period of time, when running even a little bit cold and putting it into gear out of park, the engine will rev up a little (couple hundred rpm's if I had to guess without looking) and then sort of slam into gear.

I have heard a lot of possible reasons for some of the F150 tran issues, but I'm wondering what might be the problem(s) with my specific issue.


2) Now another question which might depend highly on the conclusion of question 1: I will eventually get some 35's and will want to re-gear. If I do need to fix my differential, converter, etc, would it be easier/cheaper to just regear and have my transmission rebuilt at the same time? I'm a newb...a differential rebuild is different than a transmission rebuild right? What would the estimated cost range be for:
a) regear + differential rebuild
b) regear + transmission rebuild
c) regear + transmission rebuild + differential rebuild

Tbh I'm not really sure what all 3 consist of.

Thanks for any help!

 

Have you checked the status of the Ujoints?

 

1) sounds more like limited slip clutch chatter. Do you have a limited slip diff? If you don't know, look at the door jamb sticker at the AXLE code, if it begins with a letter (example - H9) it is. If it is, change the diff lube with 75W140 synthetic and a bottle of Ford friction modifier.

2) 2wd or 4wd? Regearing (parts and labor) is around $800 an axle. A tranny rebuild is around 2 grand.

 

Thanks for the quick responses!

I have not, but when I got the rotors changed I figure they would have noticed...that was around the time this started, but no way I can remember if it was before or after the change.

1) It is a limited slip. Changing the diff lube sounds like a good project for my skill level (lol, amateur here). Would I do it just like this: http://www.fordf150.net/howto/differentialfluid.php

2) 4wd, so both axles. Does doing the regear and tran rebuild together (assuming I would need a rebuild) make it any cheaper?

 

The front diff is not likely a LS so I would start with doing the rear first.

I didn't read that writeup, but if you remove the wheel speed sensor out of the top of the diff, its much easier to pour the fluid in

 

I talked to my pops and from what he said (I also have this damn squeek or something that has come from the back for some time now) I'm going to check the rear Ujoint first, then change the fluid (will do anyways since I don't think it's been changed once in that 126k!). I'll report back with the problems I'm sure to have lol.

 

The writeup is good. Note that the factory does not use a gasket, they use just RTV. Autozone carries a gasket for the 8.8" Ford rear, but I don't know if they have one for the 9.75".

Use 75W140 synthetic, any brand - and get a bottle of friction modifier from the Ford dealer.

Make sure you can get the fill plug loose BEFORE you pull the cover!

Doing necessary rebuilds together shouldn't change the cost.

Yes - a squeak is very often a dry u-joint! I'd drop the driveshaft and change them both. Do the inexpensive stuff first that should probably be done anyway.

 

4wd is more likely to chew up Ujoints because the driveline angles are more extreme than 2wd versions

 

Differential fluid is changed. After driving I notice no real difference. The truck still shudders on tight turns and pops out of park. Also, the ABS light came on?...any clue as to why that would happen now?

Going to change Ujoints tomorrow, praying it fixes everything.

Edit: oh lord what a long day, I know why the ABS was on...good advice to take off that speed sensor, just should have reminded me to put it back on lol.

 

ooops

atleast it was an easy and free fix :o

 

Indeed sir!

In other news, replacing the Ujoints is ridiculous...springs breaking, u joint stuck, beating on it like a **** and nothing. Sooooo frustrating.

 

Take the driveshaft to a parts store that has a machine shop and get them to do it on the press.

 

The place I'll take it to isn't open till Monday and I'm assuming the only parts store in town that is open tomorrow (authozone) doesn't have a press...this is soooo depressing. Should I just have them put the new ones in while they're at it?

 

i would think if you're paying them to take them out its not much more to have them pop the new ones in there.

 

Took it to pep boys and they spent 3 hours on it, only charged me one. In the process of hitting the damn thing so much, the pins no longer fit properly, so I'm going to have them welded I guess.