I know very little about car maintenance, I do not follow the routine maintenance guides, and I’ve rarely fixed any serious problems on a car. However, after this experience, I’ll be changing my ways.

I owe a great deal to the ford-truck.com forum members and to a handful of other websites for helping me troubleshoot my over drive problem. I never posted and never asked any questions. Simply reading through hundreds threads and thousands of posts lead me in the right direction. I especially want to thank the ford-truck.com community. I am very grateful for what I found here. The enthusiasm and expertise is simply amazing.

The following is my attempt to “give back”. I hope it helps someone avoid a run-in with the neighborhood transmission shop and the mechanical madness that goes along with the “free inspection”.

Symptoms: No Over Drive, slow/odd/different shifting in ‘D’ from 1-2-3, high RPMs, and no cruise control.

When the problem started: While driving 65mph, I began to slow down for a speed limit reduction and a wreck on the highway. The new speed limit was 55mph but, a 10 car disaster caused me to slow to a stop and then weave in-and-out of the wreckage. After passing through the hazard, I accelerated back up to the new speed limit, 55mph. At 55mph I tried to set my cruise. The cruise control did not engage. Next, I noticed that my RMPs were uncharacteristically high at 55mph. I slowed down to 40mph, and then speeded back up to 55mph, still no cruise, still really high RMPs.

“Oh no, the tranny just died on me!”

I drove it 45-50mph to the next exit and checked the trans fluid level, perfect. Checked the color, fine/normal. Checked for leaks, none. Then I drove the car slowly - going from 1 to 2 to D, and it SEEMED to be shifting fine (SEEMED because I am not a car expert and I rarely take note of the shifting differences in a car’s transmission, there was probably a major difference). Then I tested gear changes in ‘D’, it seemed to be going from 1-2-3. I had no clue what to do. So, I drove the wounded Explorer another 60 miles with my hazard lights on going 45-50mph in 3rd gear! I’m sure that is not a good idea, but I tried to keep my RMPs as low as possible and didn’t feel like calling AAA. Oh, and I tired not to infuriate passing semi-trucks.

I was busy for the week and didn’t need to drive the Explorer at all. Then by the end of the week, I decided to try and get someone’s opinion. Opened the Yellow Pages and turned to “transmissions”. What a mistake! Since I’ve read a lot of posts on this board complaining about transmission shops I will leave out a lot of details.

I got two opinions. Both said: “transmission was shot and needed to be inspected”. I asked them to check the TPS and other sensors because of what I read on ford-trucks.com. I told them the cruise control went out at the exact same time as the OD. The one crooked transmission shop owner actually said the following, and I am not joking or embellishing:

Crooked Owner: “Nope, sorry, I know that vehicle like the back of my hand, just from driving it a bit I can tell it’s shot. And no, I didn’t check the TPS like you asked because that vehicle doesn’t have one. Who ever you spoke to was mistaken.”
Me: “what? Uhhh, ok, ummm, no TPS hmm, so it has to be replaced?”
Crooked Owner: “Well, maybe, gonna be $250 to open it up, and anywhere from $1400 to $2000 to fix it, depending on what is wrong inside. Got to open it to up to find out, we can do it as soon as you want.”
Me: “Did you hook it up to the computer even….like your ad in the yellow pages describes?”
Crooked Owner: “Sorry, I would have if there was a hook up for it, most 91’s have one but it doesn’t seem like your model does.”
Me: “wow, ok, thanks uhh, I’ll be down to pick it up in 10 minutes.”

And the other opinion basically went the same way. The only solution was to: “open it up and probably fix the OD gears”.

So, I logged many hours on the net, Google, and on ford-trucks.com. Then I went to the local Advanced Auto Parts. I asked questions about the TPS and other sensors. An extremely nice guy came out from behind the counter with a computer, went out to the Explorer, found the terminal (it was in a really strange place), hooked it up, and after a couple runs, he printed out the errors for me. I was laughing the entire time, laughing at the transmission shop insanity.

“Memory Code 29: Veh Speed Sensor” &

“KOEO Code 57: Octane adjust pin – In use – CKT Grounded”. (I still have no clue what Code 57 means, haven’t had time to look that up, and the Haynes manual I have does not even list that error code.)

I eventually bought a new VSS ($20 GP Sorensen: 779-9544 Speed Sensor) and decided to try and install it myself. The Haynes manual’s section on the vehicle speed sensor wasn’t too helpful for someone like me. At first I actually had trouble locating the VSS (don’t laugh). Once I located it though, I figured I’d try because I would not have to raise the Explorer to access the VSS, the replacement wouldn’t require a lot of tools, and I was not messing with anything that would affect the car’s safety. So, I went and bought a $6 socket set for the single bolt!

The following web page link will probably be funny for most members of ford-trucks.com. I now realize how easy it is to replace the vehicle speed sensor. Before, however, I never fixed anything on ANY car or truck. I probably made an easy fix extremely complicated but, I hope this post and the picture walk through helps a complete newbie, someone like me.

Link to VSS replacement on a ’91 Explorer, with pictures, steps, and notes:

http://24.95.36.96/vss_91_explorer_replacement.html

Thanks again

 

You did good. Now go expand on that $6 socket set, and get some more tools for the next time. It is a really satisfying feeling knowing you can take care of the small things yourself, not be totally at the mercy of some so called "professionals", and be able to research a problem to see if is something minor you can do yourself, or needs a more advanced professional. A little bit of knowledge lets you see thru the BS very quickly.

PS the octane code generally refers to a shorting plug, in a wiring harness, adjacent to the computer hook up test plug, that has been removed. Removing this plug either retards or advances (I cannot remember which) the engine base timing. Find the plug and re-insert the shorting bar, clear the stored computer codes, and all should be well, or if it runs fine, with no pinging, just leave it as it is. No harm, no foul.
Dialtone

 

Dialtone,

Thanks a lot for the octane code info. Before I can act out on your advice, I’ll need to cross check and look up a lot of the terms you use. But, that is good advice because it does run “fine” and certainly does not have pinging. There does seem to be wiring oddities because of a custom fog light install that occurred before I got the Explorer. It looks like a real mess. Also, the voltage meter is bouncing all over the place when the vehicle is slowly idling or in park. Looks like I’ll be trying to learn how the computer and some of the other sensors work. Now I’ll be moving in the right direction, thank you.