Hey everyone I have an issue with my transmission and I'm not to sure where to start, and wondering if anybody has had similar problems. First off a lil background on my truck its a 1990 F250 heavy duty with the 460, and it only has 95000 original miles on it. Last year I had some issues with it shifting weird at high speeds, when I would do 50-60mph and give it a lil gas its like its in neutral until around 4000rmp then goes into gear. And only when I've been driving for at least an hour. The first time it happened I let it cool down thinking maybe the transmission got hot since I was carrying a load of wood outta the mountains. I changed fluid and filter, but when I dropped the pan I noticed the filter was not in its place and laying in the pan. After putting back together everything was fine even pulling about 20 cords of wood. Last Thanksgiving we went for a Christmas tree and it happened only once as to every time I pushed the gas like it did before. Two weeks ago it started all over again while fishing with my brother everytime i would give it gas on the highway it would do the same thing like it was in neutral until about 4000 rpm. And this time as I got into the city it was doing it at all speeds. So I checked the fluid said it was high, but didn't smell burnt. I waited a day and took it around the block and everything was back to normal, I even drove it around town for a bit. Today I'm going to drop the pan again and see where the filter is at since I got a clip to hold it in place. Please let me know if anybody has any ideas that could help me out, all feedback is greatly appreciated.

I don't have an answer, but I will say that this sounds similar to my truck's problem that ended on the highway last night. 1992 F-150 4.9 I6, accelerating/gear switching changed/stuck at 50 mph and I revved the rpms. I must have put it through the roof and broke the transmission. Maybe the engine rod shattered on mine.

All I can say is if you can find the culprit now you won't be looking for a donor truck to frankenstein. I'm preparing for the worst news from the mechanic on Monday and have found 2 (a 1995 and 1997) F250 series 4x4 V8s that can accept most of my gear add-ons and even some of my body panels due to rust on the other vehicles but solid mechanical features.

Well wasn't the filter now I'm stumped.

Sounds like the clutches are worn out, or you aren't picking up fluid.

Try putting a little extra in and see if that helps.

By the way how are you checking it? Engine running yes?

It's time to pull some codes, brother. I had one behaving this way and the culprit was the VSS (Vehicle Speed Sensor). It didn't know how fast the vehicle was traveling and was clueless on how to shift, what gear to use, and such. Pull some codes and see what might electronically be causing this headache.

Ryan

Solenoid pack could be going bad.
Could also be the wiring is bad to the transmission. It is right there by the cat.

Thanks for the input guys. First off Jebadiah, yes I always check it running and in park is what the dip stick says. And it reads great. Second O'Rattlecan I took it to a shop today that I used to trust I got a wierd reaction today it was there for two days just for them to recommend a trans service which I've already done. And I asked them to check the sensors which they said were all good but recommended some gasket also. I found it weird cause they said they they took it for a drive and it didn't do anything. And said it wasn't throwing any codes bottom line I threw away $85. The only good thing I got out of it is he said it was a bad ass truck. Third dustybumpers I have no clue where the cat should be since that was one of the first things I took out when I got it, replaced with a nice straight 3" pipe into a magna flow right under the first foot of the bed.

Hey O'Rattlecan, I was wondering which sensor your talking about the front or the rear I imagine the front. Is there anyway that I can test the sensor before I replace it. Also was it a hard job or pretty easy, I've been looking for my Chilton's but some reason that book I always so hard to find. Thanks for the help!!

It's the rear, it's on top of the rear differential.

If it's truly intermittant, as was mentioned before, please double & triple check the primary wire harness on the transmission. It connects to the solenoid pack, and it's on the passenger side of the transmission behind a small heat shield. This will deteriorate after a number of years and will require a new one to be soldered on.

Ryan

My bronco did that exact same thing - replaced the mlps and no more problem.
Here is what it looks like
http://www.ebay.com/itm/Ford-E4OD-T...ral-Safety-Switch-1989-96-99561-/321613688133

Hey kiwi thanks for the info I guess that's another piece I'll have to try out. Was it pretty hard to get to or no I haven't gone out to look for it yet.

^^ Easy to get to and replace - just on drivers side of the gearbox ..... from what i could see on my 92 the seal on the plug wasn't very good and water had gotten into the switch and corroded all the contacts. When i put the new unit in i put a pile of dialectic grease on the joint and sprayed the whole assembly with silicone sealer.

Hey thanks for the advice kiwi. I'll have to check it out this weekend. Planning on ordering a few sensors and put them in one at a time to see how things go, it might end up being a long weekend. Thanks everybody for all the info I'm sure I'm headed in the right direction just a matter of trial and error. I'll be sure to let you guys know the end result of the problem.

So today I went to order the sensors that I wanna replace, ended up running into an old friend and retired trusted mechanic. He lent me his obd scanner, I tested all options twice. The first round 2 codes came up one was tps sensor and the other was vacuum pressure, not sure they were codes because no numbers showed up. Second time I tested it nothing came up. Not sure if I should stick with the original plan of checking speed sensor and mlps, plan B the codes that came up and then disappeared. Any advice????

The TPS is a really cheap fix, and very easy to get to. It's on the bottom of the throttle body. If you were going to "throw parts" at it for a good faith effort, that one might be worth doing. The transmission does use this quite a bit to determine how hard to make the shift.

Ryan

So here's a quick question for O'Rattlecan and kiwi. When you guys changed out those sensors did you check for codes or did you just start changing parts.

I'd seen this problem before on a falcon over here so when i took the Bronco for a test drive i had a pretty good idea of what it was (seller didn't though) ..... luckily for my wallet this all happened in Cali so parts were cheap without the freight

I always changed the part based on the code. So if you have "TPS Out of Range" code, I'd throw a TPS at it. Sounds like that's what you head, hence my suggestion to throw that part at it.

My second thought:

One of the more troubled electrical problems on the trucks is that transmission solenoid wire harness I mentioned earlier (passenger side of the transmission, on the top of the pan area, behind a heat shield. It won't throw a code if it's worn out, it might throw several random codes that don't make sense. The computer is primitive and not very good at knowing what's going on there.

Ryan

OK a little update, first off we are usually probably my the driest state in the United States but this past two weeks we've been getting dumped on. Today was my day to figure this out but we had rain then snow then hot sun probably somewhere in the sixties back to rain on and off. Makes working outside on the truck a pain. So anyway I put the new tps in and was doing the mlps when I noticed one of the wires had a small cut in the insulation. Debating on throwing on some electrical tape and calling it good for a few or replacing the wires, guess it depends on how hard it is to run these wires and if I could find them. Second I was looking at the solenoid wire harness which was covered in mud, so was the mlps. I think its a good idea to re wire both of these now that I'm down there, so if anybody has any info that would be helpful to me I would appreciate it. Also where these wires go to and difficulty level. Oh and any advice getting the solenoid wire harness apart, that thing is stuck pretty damn good and I'm afraid of breaking it.

I need some help after fooling around under the truck I started it to find a check engine light and a rough and extremely low idle about 500 maybe 400 like the truck is struggling. Not sure if its from the wire harness on the passenger side or maybe I wired the harness wrong for the mlps. I also replaced the tps but that was pretty easy so hopefully I did it right. Here's what I wired. If anybody has a 90 f250 with the same colors let me know, everything online has different wire colors. Pics would be a plus.