98 F150 trans issues

Scheffdawg · Oct 7, 2010

It looks like it's getting to the end for my DD, but I'm hoping someone on here has heard of a similar issue and knows the likely cause.

First off, it's a 98 F150 with the 5.4 V8 and auto trans w/ OD. Lifted 9" on 37's and 3.73s (Don't know if that's stock or not). It's got 220k and as far as I know engine and drivetrain are original.

The problem comes when I am at freeway speeds and first drop into overdrive. After I'm in overdrive every shift, downshift or upshift, is a hard shift, feels like it's got an aggressive shift kit. Once it does it once, shifting out of OD for the first time, it does it for every shift, even 2nd-1st. This continues until I turn off the truck, and doesn't return until I hit OD again. I've been driving around with O/D off and it does not shift hard unless I've been driving for 20+ or so minutes and only at low speeds and nowhere near as hard of shifts.

I've had it at one tranny shop twice, they seem to know their stuff, but can't figure this one out. The trans speed sensor and rear diff sensors have been replaced. With the pressure guage attached to the trans while driving, the trans guy said pressures and temps looked really good before reaching O/D. After these were replaced, the hard shifting became more sporadic instead of everytime I hit O/D and also the shifts haven't been as hard, but it is still doing it. After a quick convo with an out of town friend that owns a shop, he said it's likely I'd either need to have the trans rebuilt ($1,500-$2,500?) or put it up for sale and get something else. I can't afford the rebuild, so it would be option 2 if those are all I have to choose from.

Anybody have any idea what the cause could be? To my semi-mechanical mind it seems to be electrical, but I don't know much about auto-trany's. Are my only options rebuilding or selling?

Big Red 88 · Oct 8, 2010

i would try doing a complete electronics update, shift solenoids, tcc solenoid, epc and an internal harness. if that doesnt do it than you are looking at a rebuild. if the pressures are running normal then its getting to the clutch packs but the are probably worn, along with the bands. does the od light flash when any of this happens? i work at a trans shop in snohomish, pm me if you want me to try to help you

Scheffdawg · Oct 8, 2010

The OD light did flash the first couple times it happened, but has since only flashed once or twice in the last few months.

Scheffdawg · Nov 3, 2010

Finally pulled the pan last night, replace the fluid and filter. Buddy with more experience than I said there were alot of shavings on the magnet, but he'd definitely seen worse for 200+k miles.

How difficult are those electronic parts? Can I do those by just pulling the pan or do I have to drop the whole transmission? Anybody local carry them? I found them for $35-$55 online, called the dealer and was quoted $430. The couple autoparts stores I stopped by said they didn't carry internal trans parts.

With alot of shavings in the fluid, is it worth it to do the electronics upgrade? Or should I just get a used trans for ~$700-$800 with ~100k on it and put it in?

TrikeKid · Nov 3, 2010

Scheffdawg said:
Finally pulled the pan last night, replace the fluid and filter. Buddy with more experience than I said there were alot of shavings on the magnet, but he'd definitely seen worse for 200+k miles.

How difficult are those electronic parts? Can I do those by just pulling the pan or do I have to drop the whole transmission? Anybody local carry them? I found them for $35-$55 online, called the dealer and was quoted $430. The couple autoparts stores I stopped by said they didn't carry internal trans parts.

With alot of shavings in the fluid, is it worth it to do the electronics upgrade? Or should I just get a used trans for ~$700-$800 with ~100k on it and put it in?

SeaTac Trans sells parts local, as does Transmission Sales & Service in Tacoma. Shift solenoids and the other sensors you should be able to do just by pulling the pan. I don't know of anywhere up that way for parts though.

Is it shifting into od at the right time? Has anyone that's looked at it had a scan tool capable of watching the output of all the sensors as they drive?

Scheffdawg · Nov 4, 2010

As far as I know, no they have not. The only diagnostic equipment I am aware that they used was a code reader and a pressure gauge hooked up to the trans while driving. Are those inidividual sensor readers common to most specialty trans shops?

It feels to me like the shift points are correct, or at least consistent since I've owned it (3 yrs). Though I do have 37's and nothing has been reprogrammed from stock.

Big Red 88 · Nov 4, 2010

Yes, I can sell them to you locally (Snohomish), with a lot of metal shavings personally I would say it's not worth it to put the electronics in it but I didn't see the pan myself, if there is a lot of metal in there then it's going through your whole trans and embedding itself in your clutches and bands and eventually going to tear more stuff apart but like I said I didn't see the pan so I can't tell you how far it is down that path. As far as the od light flashing that means you have a code in your trans and why they couldn't get it I am not sure ford usually has a spot for memory codes. Give me a call @ (360) 568-0220 ask for Jaden, it would be easier that way since I am not on here all the time. If it wasn't too much metal then let me know and I can get you the electronics. You can change the solenoids with just dropping the pan although you do have to pull the linkage to do the epc

Scheffdawg · Nov 4, 2010

Thanks for the help, I'll probably give you a call sometime next week to set something up.

They did pull a code from the port under the steering wheel, but it was an intermittent speed sensor code/radio interference (I wasn't clear if it was the same code with 2 possible meanings or 2 seperate codes). Both speed sensors were replaced and problem persists.

I should clarify, the fluid itself was in good condition, not too dark, no noticeable metal chips, but the magnet in the bottom of the pan had lots of shavings attached.

TrikeKid · Nov 5, 2010

A scan tool that can monitor sensors is something any dealer would have, I doubt a trans shop would have Ford's scan tool (NGS or WDS) but I believe the tool truck brands have scanners that can monitor sensor outputs. I did a rebuild on a taurus transaxle that had a hard shift problem, drive it while monitoring all the sensors and that lead me to the tss that hadn't been plugged back in when the trans went back into the car.

I don't know that I'd throw parts in a 220k transmission, but I also have a little experience fooling around inside an automatic and could do the rebuild in my garage if I wanted.

Big Red 88 · Nov 6, 2010

i do have a scan tool to watch the sensors so if you want i can do that. the metal shavings on the magnet is probably the sun gear pitting out, common problem with those trannys. speed sensor is definatly going to make it shift wierd, your shift pattern is ran off of it but your computer needs to see the fault a certain number of times in order to set the code and if its intermittent then it will take a while. i have seen the differentials go out and cause that since the speed sensor is in the rear differential if there is a bunch of metal on it then it throws off the speed sensor intermittently (the speed sensor is magnetized and runs off the abs ring on the carrier of the rear diff) is your abs light on? i have also seen an intermittent short in the wiring so i would check that too, follow it from the sensor up and see if its rubbing on something or that kind of nature thing

we had a jeep come in that every time you would step on it hard it would set the check engine light and immediatly turn off after you let off and after a few times of doing that it would put the trans in limp mode until you shut it off, what was happening was the motor was torquing enough to rub the harness on the firewall and it would short out every time you stepped on it hard. had to do the motor mounts and fix the harness. (just an example)