I will claim up front I am a rookie but I do have the desire to learn. I have read many threads on this site and elsewhere before I decided to post. Any help is appreciated.

While reading through the many trans. threads I was able to identify the type on my 2001 F-150 Automatic 4.2L V6 as a 4r70W. In another thread someone was kind enough to describe the term slipping as "the engine revs go higher than normal and stick for a while before shifting.

If this is a valid description for slippage then my problem is not slippage. My problem is most noticeable between 40-60mph and during warmer days. On colder days, approx 40F or lower, the issue does not seem to occur as consistently or may not occur during my 22-mile commute.

Anyway, what happens is; between 40-60 mph the vehicle kicks, stutters or jumps (for lack of better words) continually. The engine rpms do not increase or remain high as described for slippage, but rather remain low (below 1500). When this does occur I can accelerate thru the problem. I can then back off the accelerator when the speed gets above 60 mph (and I think when rpms stay above 1500). If my speed (and/or RPMS) lower again the problem will return. Everything is also fine (or so it seems) at speeds below 40.

I went to do a fluid change, as recommended throughout many threads, but the mechanic recommended not to as it was very clean. Any suggestions on this? Does this issues have a specific term? What are the correct rpms at these speeds?

Thanx
DXJ

 

It really sounds engine related, like a bad coil pack or wire or spark plug. Mine did something like this when a coil on plug (5.4L year 2000) and it was a little more unpredictable and patternless. Does you're engine seem fine and you basically know it's the tranny? I've had to get mine rebuilt as we speak (I'm truckless ) so maybe that particular gear or o/d is messed up. I wish I could offer more insight.

 

Sounds like and ignition problem to me as well Blue. It's called a "low grade misfire".

Usually happens @ 45mph right after the trans hits Over Drive you get a "Bucking" ..

Plugs - Wires - Coil Pac...
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Good-luck with the rebuild Blue - It's a different world when all that power stays at the rear wheels

Your really going to want that Supercharger after this haha..

 

Thanx for the reply. The Coil/plug has been suggested before. I had put a car chip on the OBDII and monitored the engine rpm and timing for a couple days. I couldn't tell if anything was odd or not. Perhaps I should go ahead and change out the Coil. plugs and wires to see if it eliminates the issue. Truck has 125K on it. It is probably due for this anyway.

 

At 125k you need plugs, wires, and a coil pack. I recommend OEM Motorcraft if possible.

 

The mechanic is wrong. You can't tell if ATF is worn out by looking at it. The friction modifiers get depleted and that changes the way the fluid works. It can cause torque converter shudder. If your fluid has at least 30,000 miles on it you should change it no matter what it looks like.

Having said all that, I agree that this is probably an engine issue.

 

+ 1 on that.. Don't let them talk you into Autolite's , just go somewhere else if they don't have Motorcraft. I don't know about the V6's, the stock 5.4L's are picky as hell when it comes to plugs and won't run right.

Only three brands work well with the modulars that I know of - Motorcraft, NGK and Denso's..

Motorcraft is the OEM plugs and your best bet on a stock - lightly modded motor.

 

That's true . Have you ever driven one these trucks when the Friction Modifier brakes down in the rear end? Holy Hell!! I was all over the road - thought I had a bent rim or something

I can't imagine that happening in the transmission..

 

Jbrew, haha brotha, I got the truck back. It shifts like a new truck with a higher stall converter and HD components throughout. I don't exactly know what was done, I'll find out when I pay him, he'll show me. Procharger here we come boy.

Anyways, as far as the v-6's go there dxj, it might be time as mentioned for a good ol tuneup, wires are probably weak, plugs and coil pack too. I don't know if or why the plug choice is a big issue like the 5.4's. The 4.2 is essentially a 5.0/5.8 with 2 less cylinders, and we've run a few different plugs in the 5.0's we've had. Bosch was decent, Motorcraft were always good and Autolites. I think the 5.4/4.6's are a bit, ALOT I mean testy with plug choice. Seeing how you might be considering this tuneup, the dealer might be a good if not only place for these parts. The coil pack's I haven't seen alot of outside of the dealer.

Worst case scenario you have the same problem, but did preventative maintenance anyways. Good luck.

 

Great Blue!! That's good news !! It didn't take that long either...Something I learned since joining a few tranny forums. You get the best info and honesty just going down to a trans shop and talking with the people down there. Tips and tricks you don't really here of. Those guys are in a class of there own...
Do you plan on going all the way with the Procharger ? ie - 3 core , bumped up injector's and a tune? Or the two core , stock injector's , stock tune?

 

anyone mention dielectic compound is his friend when doing plugs n wires?

 

Good point ! Silicone wire sealer as well for that V6..

:santa:

 

Yuppers, at least that's what I want to, 3 core, injectors (still have stock ones)so I'll up them, reprogramming my superchip (already in place) it's a Sean Hyland piece, also upgrade the fuel pump I guess. Trust me, this won't be for a while yet, maybe a late 08 project. Gotta watch the $$$ for a while, things are REALLY BAD here in Windsor and I'm between jobs. Gotta behave

Good call on the dielectric grease, these like 5.0's aren't as picky, but it never hurts and should always be done.

 

Yea , if your going with new components , that's well over 5 grand. I want to do that to my 98 after I get a new Daily Driver..
I'm a operating engineer - job cuts and layoffs been happening here . I'm between as well. New hires and call backs won't happen until mid March..Trying to find something in the mean time is a task. Roush offered me a job for 10 bucks an hour lol - Unemployment pays more than that!! So it's tough out their right now, I know..