91 explorer trans porblem/ no overdrive
 

Hey i have a 91 explorer with an auto trans ans electronic 4wd. the problem i have is that about a week ago i was crusing down the highway at 65mph. now usually at this speed i have the trans in OD but for some reason the rpm's came up on the tac as if it were in drive. Now at 65 my tac usually reads about 1500 rpm in OD and 3000 in D. so now no matter what gear i have the truck in OD or D the engine runs at 3000 rpm and it is killing me on fuel and i don'teven want to know whar it is doin to the engine running at that rmp for the hour or so i am on the highway. Anyway i have i have a manual trans in the back of my exporer i took out of my brothers 91 explorer when he blew the engine. can some one tell me how hard it will be to swap the auto over to the manual that is in the back of the truck or is the problem with my OD easier to fix.

let me give you some background on this truck of mine. when i bought it a little over a year ago, i was living in arizona with my girlfriend. when i mived back to NJ i drove the truck back. the trans went while i was in oklahoma and it was just the pump seal so it was an easy fix. ever since then i has has a slow leak and is still leaking. now the 4x4 is electronic and the 1 i scrounged out of my brothers explorer is a manual trans and trasfer case. is it goinf to be real hard for me to conver everything over from automatic and electronic to all manual?

Whether it will be easier to switch to a manual tranny or fix the OD will depend on what is wrong with 4th gear. 3-4 shift is electronically controlled by the PCM, so the first step in diagnosis is to determine if the fault is electrical, a faulty sensor that is preventing the computer from deciding to shift into 4th gear, or a mechanical fault in the transmission.

Long term, though, the A4LD has a fairly poor reputation. Whether you do it now, or later, most people on boards like this will recommend that you put that manual tranny (should be M5OD) in.

The A4LD may have a poor reputation, but more than 95% of its problems come from abuse such as overheating, lack of maintenance, driving up hills grades with the torque converter unlocked, and running them low on fluid. The A4LD can handle a lot of torque is its basic operating principles are understood. The A4LD will also last a very long time if it is properly maintained.

You may very well have an electrical problem, but in order to advise you what the problem may be, could you give us a brief description of the transmissions maintenance history.

well unfortunatly as a mechanic it looks bad on me to say this but i have had very little time to maintain the tranny or any thing else on my explorer. i know i ran it low on fluid and i don't know when the last time the trans filter was replaced. let me explain some things before all you mechanics get on my case for this.
First when i was living in AZ i had kept up on the engine tune ups. every 3000 mile my truck had the oil changed, new plugs, wires, filter, ect. unfortunately i am not working as a mechanic. at the time i was in AZ i was working as a collercial trucker and wasn't home that much so the explorer basically sat for the week or 2 i was on the road. now back in jersey i am still doing the trucking thing but all local work so i drive my truck every day.i run about 12 hour a day and i start at 5:30 am, this means i am up and out at 5am and don't get home till 6pm. so i have no time or a place to work on my truck during the week. And since i live in an aprtment building, managment won't let me work on my vehicles in the parking lot( the got pissed when i was swapping tranny's in the parking lot on my Dodge Daytona[ I know bad choice of vehicle lol]) So now any work i have to do on my truck has to be done at a shop my father works at and usually done on a day in the week when i am not working because his shop is not open on the weekend. so my lack of workspace and tools. are one of the main reasons i haven't kept up the maintinance on my truck.

Now back to the tranny. i know when i have tried to shift it from D to OD at speed nothing happens but when i switch it back from OD to D i can feel the tranny shift. as far as i can tell i think i might have blown the OD gear. right now the other problem i have is that the trans is slipping and won't shift right untill the tranny warms up. now for some reason when i check the fluid level it reads full. so this is something that helped contribute to me running the tranny low on fliud. the false reading led me to believe the fluid level was good. but i would like some advice on how to fix this problem. i love my truck and love ford. the most dependable vehicles i have ever owned. and i have owned alot lol from ford, dodge, izuzu, suzuki, nissan. but fords are the best for me.

It is most likely the 3-4 shift solenoid that has failed. Check and make sure that the PCM is commanding the shift first though. The 3-4 and TCC solenoids are known to fail or become gummed up or clogged with junk. Pretty common problem actually. Its easy to replace them though.

Ok, if the tranny won't shift right till it warms up, that leads me to believe the tranny is low on fluid. The fluid superheats and expands restoring seemingly normal function, but the transmission is actually burning up inside.

You should definately get it flushed out with the method I just outlined. Or find a shop that does it that way. Don't let them hook the machine up to it, there is a slight possibility that it could make the issue worse. I don't know what to tell you on this one, but considering the overall lack of maintenance in the transmissions history, it has likely sustained serious internal damage. My trans was run low on fluid by the previous owner, which caused me to have to pay up for a total rebuild since it scorched just about everything inside. Hopefully yours is not as bad as mine was.

not looking to spend much money on this so it seems more likely that i will just convert the auto/electronic trans and transfer case ofer to the namual ones i have. i mean besides the tranny problem mt 4wd has not worked sincce i bought the trck. so i will just swap trans and all the 4wd stuff. got it all for free anyway and i know they are in perfect condition. lol actually kept up on the maintiance of my brothers truck more then mine so i know all the stuff for the manual trans will work.

So rather than fix your problem (which is most likely a simple one) you are going to just tear the drivetrain out?

The 4x4 not working is probably due to the shift motor. You can take them apart and clean them up and usually that fixes it. The slipping is probably due to low fluid like Bear River said and the lack of overdrive is due to a solenoid that can either be cleaned or replaced.

To each his own I guess...

A few weeks back I just picked up a b2 cheap, seller stated that he put in a explorer tranny in it but it didn't shift into OD when it was still in the explorer (why anyone would go through all that for a tranny they thought had no OD is beyond me but not the point).
I bought it for parts but the boy and I got to messing around with it and got it running to find out what was good and what was bad. Sure enough took it for a ride and found it in fact would not shift to OD but would shift into every other gear fine.

Had some other issues also that lead me to believe the computer may be bad so I changed it (had one on hand), Sure enough changing the computer fixed the other issues and also fixed the OD problem, now it shifts into all gears just fine.

Anyway just something to consider, I'd at least try it before taking it all apart. If you do be sure to get a computer from one with a automatic trans, tried one from a b2 with a manual trans and it didn't shift into OD, not sure if they're different but it didn't work. (The computer we tried from a b2 with the manual trans is a known "good" one.)

it's not that i want to rip the drive train out. i would just like to fix the problem at the lowest cost possible. I mean i'm not that great at repairing transmissions. my training is more in vehicle electrical systems. i have a chilton cd that covers my truck but all it says is to seek profesional help when having trans problems. i mean if i had a break down of the trans and all the specifications for doing the work then i could probably pull the trans anf fix it. i mean if you guys have a way for me to get the specs for this trans please by all means let me know. i have a feeling that the 4wd problem is electrical in nature. i mean i have pulle tranfer cases before and rebuilt them on my old 85th bronco but that was a manual transfercase not an electronic one. to be honest all this electonic crap in the trans and engine suck in my opinion. i liked it better when i could tune a carb with a screwdriver. now you need computers and all that crap just to diagnose a problem and i just don't have the equipment to do the comuter work. i mean i am used to working on my back under a vehicle and jusr dropping the trans on the ground. never had trans jacks or engine jacks. pulled the trans and tranfer cases out of my 85 bronco and my 83 f250 in my driveway lol that is what i am used to lol

You really didn't say what the 4X4 problem was, may just be the little shift motor on the transfer case. Shouldn't be to hard to figure out what the problem is.

Electronics are fantastic if you know what you are doing. It takes a little more education and some different tools than a carb tuneup or valve adjustment, but if you embrace it and genuinely learn how to work with it the computers make life much easier. Computers are here to stay.

Also, get a hold of the Ford factory service manual for the truck on a CD. That is the BEST tool that I have for my vehicles. Let me know if you can't fine one.

last time i asked about anything from ford whether is was about parts or a tech manual the dealerships around here tole me they can't give me that info lol but thanx fot the links i'm sure they will help. i'm off all week so i'll have to see what i can figure out. just wish it would stop raining x(

PM'd ya with some info on where to find one

How do you determine if the problem is the computer? Is there some way to test it? I just read my codes and got no error codes other than I forgot to open the throttle when it told me to. I remembered to turn the steering and pump the brakes and got no error codes for that so to me it seems like the computer is working, at least as far as the codes go. Mine is a '91 so it won't give me the three digit codes.

Mine will not engage at all if I put it in O/D but seems fine if I put it in D, R, 2, or 1. Does that sound like a solenoid problem? I can sorta hear or feel it when I put it in O/D but then nothing.