Well, I’m glad that it probably isn’t the transmissiom. I never thought it was.
Marworth, please keep us informed of what they find. With the original transmission being burned up, replacement was the only option, so that was needed. I wouldn’t recommend driving it too far though in this condition. I would highly recommend having a good external transmission cooler installed and a trans temp gauge to monitor trans temps. If you have to take it a good distance to a good mechanic, I would recommend towing it since we don’t know what the problem is yet. You have a good Ford reman in there. You don’t need to burn it up too. Ford probably won’t pay to replace that one too.
transman
Yeah, please do. All this expense and lost time because some little thing was not working properly.
OK, but to who? Find a Ford dealer willing to work on it? Find a new Tranmission person? What kindof mechanic. I do have to take it out of town because no one here was willing to work on a vehicle of that size. How do I find a good mechanic?
The fact that it’s a motorhome should not matter; it’s still a generic Ford F-350 chassis/drivetrain and any competent Ford mechanic or Ford dealer should be able to sort this out.
What I’m starting to question is the competency of this garage that the motorhome seller sent you to. Is the seller of this motorhome footing the tab on all of this?
I won’t accuse them of anything but I will say that sometimes things like this can be a conflict of interest and in certain cases can lead to a certain amount of outright BS if a seller is paying the bill.
Transman will probably get the gist of that. 
I also question why an apparently independent shop is buying, allegedly, a reman transmission from Ford, replacing the Overdrive switch not once but twice, and sending the ECM to Ford for a “rebuild”.
Why the heavy involvement with FOMOCO is puzzling to me.
They’ve also thrown a fuel sensor at it? WTH is that on a 1990 model; an O2 sensor?
I’m on the fence about whether to buy into this shop or head to the sporting goods store for some chest waders. 
I once had an Olds Cutlass Ciera with similar symptoms. In overdrive, it seemed like it couldn’t make up it’s mind, down or up? The problem ended up being a bad MAF sensor.
"And Ellis, The transmission was burned up and needed to be replaced. How can that NOT be a given. A vehicle will not operate with a burned up transmission"
Who said it was “burned up” some trigger happy transmission shop? And just what does “burned up” mean. The OP said it did fine with overdrive locked out. I guess the last 2 are “burned up” also since they act the same as the original. You said yourself that “A vehicle will not operate with a burned up transmission”
Ahh, this thread got a little too slow for Ellis so he thought he would liven it up again. Bye Earl, have a merry Christmas.
transman
Ok, everybody are you sitting down?!!! Salinas Ford Truck Center found and fixed the problem!! Yahoo! OK, so I know you are all anxiously awaiting the answer! It turns out it was NOT the Transmission! It was a wire that got lodged underneath the air filter and wore the insulation off the wire. The short in the wire was causing an intermittent loss of power. Once that was repaired the problem stopped. In fact, on the drive home she drove better than every with more power!! Unbelievable. Thanks to you guys and a big thanks to Ford!!!
Awesome. Glad they found the problem.
transman
EllyEllisDecember 2011Edit Report
TRansman, here is a post of your’s from December. "And Ellis, The transmission was burned up and needed to be replaced. How can that NOT be a given. A vehicle will not operate with a burned up transmission"
Then I said
Who said it was “burned up” some trigger happy transmission shop? And just what does “burned up” mean. The OP said it did fine with overdrive locked out. I guess the last 2 are “burned up” also since they act the same as the original. You said yourself that “A vehicle will not operate with a burned up transmission”
Seems the transmission was NOT burned up.
Goes In and Out of Overdrive and burns up the Transmission!..
This is the title of this thread. On this board as with any other board I have ever been on, all we have to go on is the information given to us by the OP. Marworth has yet to give us any information to the contrary that the first transmission was not burned up. An automatic transmission hunting between gears can and will overheat and burn up. Depending on how bad the hunting is, the converter clutch has no time to lock up. That alone will cause overheating of the transmission, damaging it. The constant hunting will overheat the friction elements. Transmission fluid can be burned and the vehicle still be rolling but in this case, for how long?? How many times do you see on this board, “I checked the fluid and its black”. Burned up transmission fluid means your transmission has overheated and is on borrowed time. Its basically considered gone to us trans techs. Until Marworth says different, I will go by HIS statement that the first transmission was burned up. Now, on to the second and third transmissions. It is plainly obvious that both the second and third transmissions were good, the problem was in the engine side and Ford found it. This is why you commonly see me telling a poster to have a good drivability tech check it out before condemning the transmission. This comes from 29 years building automatics.
transman
An automatic transmission hunting between gears can and will overheat and burn up.
This was a known issue with the 80’s GM S-10/15 with the 2.8L V6. The engine was so underpowered that it was constantly causing the tranny to shift gears. When GM replaced the engine with the 4.3…transmission failures went way down.
Yeah, I know, that’s why I limit the up and down shifting as much as I can.
Transman, you still refuse to believe what the OP said., " the transmission worked fine with the overdrive Off" If it were burned up, it would not work fine, would it??? It worked just like the next two!
MarworthJanuary 11Report
Ok, everybody are you sitting down?!!! Salinas Ford Truck Center found and fixed the problem!! Yahoo! OK, so I know you are all anxiously awaiting the answer! It turns out it was NOT the Transmission
“Transman, you still refuse to believe what the OP said., " the transmission worked fine with the overdrive Off” If it were burned up, it would not work fine, would it??? It worked just like the next two! "
Once again Earl… Goes In and Out of Overdrive and burns up the Transmission! This is the title of the post.
Read this next part carefully:
Transmission fluid can be burned and the vehicle still be rolling but in this case, for how long?? How many times do you see on this board, “I checked the fluid and its black”. Burned up transmission fluid means your transmission has overheated and is on borrowed time. Its basically considered gone to us trans techs. Until Marworth says different, I will go by HIS statement that the first transmission was burned up.
Ok, everybody are you sitting down?!!! Salinas Ford Truck Center found and fixed the problem!! Yahoo! OK, so I know you are all anxiously awaiting the answer! It turns out it was NOT the Transmission
It WASN’T the transmission causing the hunting… I agree…Thats why I told him to have other things checked out because I didn’t believe the transmission was causing the hunting, BUT…An automatic transmission hunting between gears can and will overheat and burn up. Depending on how bad the hunting is, the converter clutch has no time to lock up. That alone will cause overheating of the transmission, damaging it. The constant hunting will overheat the friction elements. This is why I believe the ORIGINAL and ONLY THE ORIGINAL trans was burned and until Marworth refutes what HE said, I stand by what I said. Like I said, I’ve been doing this for 29 years. Have you even seen the inside of an automatic transmission??
transman
Transman, Well the Op said the trans was burned up because some SHOP told him it was.
Did you see the inside of this transmission??
I have no doubt that you are good at repairing transmissions, with 29 years experience.
I also have no doubt that you overhauled many that didn’t need it. As was the case of the OP in this post.
You do not know that Ellis. Transmissions WILL burn up from excessive hunting. If his first transmission was hunting for any extended period of time it could have very we’ll been burned up. Rolling or not. You and I have the exact same information. Only difference, you don’t know transmissions. I’m inclined to believe it is burned like he said until he clears it up. This is from personal and professional experience. If he comes back and says the fluid was not burned then you guessed right. Yes I have opened up many transmissions that obviously didn’t need overhaul. My shop is a rebuilding shop only. I do not do R&Rs. All my work is walk in, drop off trans. I rarely take part in the diagnosis test drive unless they come to me first. Hopefully marworth will clear some things up.
transman
Well, we will never know the facts. the original trany is long gone by now. I don’t know and you don;t know. You say yourself " I rarely take part in the diagnosis test drive unless they come to me first. " I am willing to call a truce if you are. ’
The reason I get quite a few good transmissions crossing my bench is that people out there who know nothing about transmissions are diagnosing their own stuff and are listening to others who know nothing about transmissions.
transman