'91 Explorer Shuts off when put into gear

[Dmixon850]

I just got this '91 Explorer which is in great shape for it's age. It needs some little things done with it but it had the motor replaced two years ago and the transmission replaced a year ago. My problem is that when you shift it into gear, it is like it hits something hard, locks down and chokes the motor down and shuts off. It runs perfect in park or neutral. Pat the gas, fine. Idles fine. Now I had a mechanic come out to troubleshoot it and he thought it might have been the fuel filter. Replaced it (which it really needed) but it still does it. (Now if it sits a while, it will move about ten feet the first time you crank it an shift it into gear but then it stutters and locks down and shuts off.) So this mechanic jacks the rear end up and put it on jack stands. He turns the wheels and they are very hard to turn so he thinks maybe the brakes are locked up. He removes the wheel and drum, but the brake shoes are fine. He has me crank it up, put it into gear and it works just fine. Reverse-fine, drive-fine. So he put the drum back on, we do it again, it turns fine. So he put the tire on and we do it again, ok. He drops it on the ground and it moves ten feet and then locks up. He jacks it back up and when I shift it into gear, it's locked up.

Now, I have been told it could be the Air control sensor, the neutral safety switch or (this mechanic said) the rear end is shot. Any ideas? Any advice, suggestions or references would be GREATLY appreciated!!!

This is a 1991 Ford Explorer 4X4 4.0 V6 Automatic.

 

[larrydd999]

Has anyone checked the transmission fluid? Is it up to the proper level and/or does it have a burned odor? My second thought would be the torque converter. I can't believe it would be anything past the transmission.

 

[murkinstock]

My second thought would be the torque converter. I can't believe it would be anything past the transmission.

Yeah, torque converter was my first thought. That's what it seems like to me. I'm not expert by any means and have virtually no experience with transmissions but I still have a good understanding of how they work. (from videos and looking up how they work) Either that torque converter or the tranny is my guess.

Good luck!

 

[natenkiki2004]

All I can say is that it definitely wouldn't be the neutral safety switch. That thing's purpose is to prevent starting while in-gear. It may also trigger the rear backup lights but that's it.

 

[FR-425]

It could be the rear end, gobbled up the spider gears.

Easy test.

Just jack up one rear tire and turn it by hand you'll feel it and hear it if it's junk.

 

[murkinstock]

I guess it's possible it could be the rear end. The reason it doesn't seem like it to me though is it sounds like he doesn't even try to move and it will die. He just puts it into gear and it gets choked. Right? You don't even try to move before it dies? That's why it seems like the torque converter to me. Do I make sense? lol

 

[FR-425]

OP said he rolls 10 feet and then it locks up.

 

[FR-425]

If it's not the rear end it is probably a broken spring on the TCC shuttle valve, (red arrow) causing the torque converter to lock at a stop or low speed. It would be the same as pop'n the clutch on a standard with your foot on the brake.

You have to pull the valve body to fix, but a full rebuild is not nessesary and it can be done with the trans in the truck.

Here's the spring in question:

 

[murkinstock]

Oh alright. I missed the part about it rolling ten feet. Sowwy.

 

[larrydd999]

I caught the 'runs 10 feet' but gathered from the rest of the sentence that it was only the first try when it's been sitting a while. I'll certainly defer to FR-425 and do appreciate his thoughts and his image. Hopefully when Dmixon850 gets the problem solved he'll share it with us.

 

[Dmixon850]

Well, I'm still not sure what it was causing it but I will try to find out to let others know. The tranny fluid was fine but was looking dark and smelled a lil burnt. I believe the tranny is/was on it's way out but I was told by another mechanic that is was the torque converter. I ended up trading it for a car in order to be able to get back to work as it was my only transportation and I needed a vehicle but I know the people who have it and will find out if they got it running and what they did to it. It broke my heart to see it go though. I love an older truck. By the way, I'm a woman. LOL! I have also been a mechanic for 20+ yrs but it's been motors (car/truck and boat), tranny's just are not my thing!