A4LD stuck in forward, even while in neutral and reverse.

Hi to all. This is my first post, but I have found information posted here very useful. Thanks to all of you who have shared your knowledge!

The transmission I'm having problems with is an A4LD in a 1991 Explorer. I tried searching, but was unable to find information about my specific problem. I did find a thread that referred to an "always in a forward gear" A4LD problem, but the thread contained no information about how to fix it.

Here is the history- I purchased two explorers, one with a bad transmission (no forward, no reverse, nothing at all) and another for parts that allegedly had a good transmission. I took the bad tranny out and swapped it with the one that was supposed to be good. Well... the "good" transmission was stuck in drive/forward. It tried to move the vehicle forward even in neutral. In park you could feel that although the parking pawl is holding the vehicle in place, the engine is under load, as if it was in drive and you were holding the brakes.

I took it for a test drive and it went about two blocks then started slipping. I ended up towing it back home.

Following the valve body diary on this site, I removed, cleaned, and checked the valve body. All the valves were checked for free movement and any that were even slightly sticky were removed from the body for cleaning. The reverse servo was removed, checked and cleaned also.

There was some metal in the Oil pressure booster valve - Oil Pressure regulator. The metal was probably restricting its movement.

I did not find any other suspected problem.

The amount of residue in the pan was minor. Less than what I have found in other transmissions I've done filter changes on.

There was a spring in one of the oil passageways. I read on another thread that some rebuilders put springs in the passageways as a filter of sorts. So this is probably a rebuilt transmission. Odometer on the donor vehicle reads 68,000 miles.

The valve body was reassembled correctly as per the diary. The screws were tightened evenly with a torque wrench.

Even though band adjustment should not have anything to do with the problem, I adjusted them anyway. The original adjustment was very close to what I ended up with after readjusting.

I did not see anything obviously wrong with the reverse servo, but it did slide into its hole fairly easily. It felt to me like there was enough resistance to indicate the O-rings would seal, but I haven't installed a new one so I don't have any reference for comparison.

The gear selector linkage is attached and is working properly.

After reassembling and filling the trans to the correct level with the correct oil, it is still stuck in forward. Vehicle is still up on jack stands- I haven’t bothered to take it on the road since it still isn’t working properly.

When it is in drive it defiantly shifts through 1, 2 &3 gears. I can’t tell for sure if it’s shifting into OD. I did not spin the tires over 55mph on the jack stands.

In reverse and neutral the tires spin forward. When the selector is moved from reverse or neutral into drive I can feel it engage something, like it normally would if you shifted from neutral into drive with a good transmission.

In park the engine is under load, as if it was in drive with the brakes on. If I take the trans out of park without holding the brakes, it pops out of park immediately spinning the wheels forward.

Can any of you help me diagnosis this? Thanks in advance for whatever helps you may provide!

No one has experienced this problem before, or knows what it might be, or how to fix it?

Anyone know of another forum where it would be worth trying?

Glacier991 or Brooklynbay????

Perhaps Glacier991 or Brooklynbay have a suggestion?

Welcome to this forum! Did you see if the Z link is bent? # 31 in my list of useful threads has information on the Z link: http://www.explorerforum.com/forums/showthread.php?t=155599. The spring filter is for the TCC. This link has information on the spring: http://www.explorerforum.com/photopost/showphoto.php?photo=22153

Brooklynbay, thanks for the info.

The Z-Link looks OK. The linkage doesn't appear to be the problem since in "D" the transmission automaticly shifts through 3 forward gears up to 55mph, and in "P" the parking pawl is engaged (although you can feel the vehicle trying to drive forward against the pawl. Imagine you are in "D" with the brakes on).

In "R" and "N" the vehicle still drives forward but doesnt auto shift gears. When I move the linkage from "N" to "D" if you pay attention, you can feel there is an engagement of something in the transmission and then it auto shifts through the gears normally.

My first thought was a valve body/gasket issue. Since you suspect the "good" trans has been apart before, and obviously had a problem when you bought it, I think I would toss the whole thing in the trash can and start over. You just don't know what you have. You could have a bad case, wrong valve body, who knows what. If you can find someone who is very familiar with these transmissions and can tell you exactly what you have, then fine. Otherwise, I would start over with something I knew was right to begin with. You could chase this forever otherwise.

you seem to be more dedicated to finding the problem than i was. well if you do decide to actually chase the problem and do find it, lmk. i would love to take apart my old tranny,which has the same problem, and rebuild it to be tougher than the average tranny. good luck with this though, like i said earlier, it would be easier to just start fresh with a new one.

Thanks for the replies.

goatlegman, my dedication is baised on the economics of the situation. I got the two Explorers very cheap, but the age and overall condition do not warrant putting more $$ into the project.

The same applies to my labor. I have invested too much time already. At some point, the trans either gets fixed cheap and easy, or I cut my losses and junk the vehicle.

The rig was for my son. It was a learning experience for him, he helped swap the transmission and hopefully learned a bit. I have in the meantime found him another rig that was a simple fix-up. The Explorer is still sitting and I'd still like to fix it enough to sell.

Any other advise would be appreciated.

Same problem

For what its worth, my A4LD was doing the same exact thing. I tried the cheap way first w/ doing the shift kit (Transgo) per one of the sticky threads. But that didn't work so I dropped it out and am going through it now, heres what I've replaced so far: had the torque converter rebuilt, ( rebuilder said the splines were about ready to go anyway) replaced the 2 forward servo pistons, (rubber was broke on one, cracked on the other) both front bands, (one had a chunk out of it) vacuum modulator, (leaked) lockup solenoid on valve body, (no click when excited). Have about 500 bucks in parts in it and about ready to go back together. Thing has 196,000 miles on it but I don't think the tranny got the love the rest of the truck did. Good luck!

Good information! Thanks for posting.

I am very interested in your final results. If I understand your post correctly, it would appear that you did not find anything wrong or damaged to the point of not working, except the Forward Servo's?

Can we reasonably conclude that the damaged rubber on the Servo's was the cause of your transmission being stuck in forward?

Yeah the two servos and the converter lockup solenoid was bad, oh and the vacuum modulator were all bad parts. But yes I will let you know how it comes out, I'm fixin' to start assembling here soon!

i am also vey interested in your outcome crawlinbronc. im gunna rebuild the one i have sittin. i just wanna know what to fix bfore i dig in

Update

Trans is finally going together. Did find the prob with reverse. Clutch pack was smoked. Ended up having to buy new steels for it also. I can't say enough good about Transtar Industries. www.transtar1.com Darn helpful and they sell to the public. Wish I would have known about them 4 years ago when I built the A4LD in my moms aerostar. I'll let you folks know how it comes out, when done.

Thanks for keeping us updated! What cluch pack was smoked? The Reverse pack? What do you mean by smoked? Were the friction discs worn out? How do you suppose that kept the Transmission stuck in Forward all the time?

It's a good idea to install a manual valve index sleeve: http://www.transmissionpartsusa.com/A4LD_Manual_valve_index_sleeve_p/400-005694701.htm

Forward Clutches

Brooklynbay is on to my problem I see! It was the forward clutches that were smoked. And smoked I'm meaning the friction material was worn off and the metal that was left kind of welded itself to the steels. But the other clutches in the same drum (other end) were just fine. Looked good. So I bought new steels from Transgo for $1.74 a piece x6. I'm no tranny expert, but i was looking at the chart that tells what is applied and what is holding when it is in whatever gear and the forward clutches are applied in every mode except for Park, neutral, and reverse. Sooooo that leads me to believe since they were all stuck together, they couldn't dis-engage when in those three modes, which is what it was doing to me. It felt like it was trying to go forward in park. I was nervous about doing this tranny, I don't remember being to worried on my moms, but hers didn't have this many issues either! But all in all this has been pretty easy so far. And fun! Nice to have you guys around to bounce ideas off of also. Will keep you posted!

p.s.

Sorry I forgot BrooklynBay: I take it you recommend that Sonnax sleeve? And also what kind of pump alignment tool to have / recommend? The tranny shops around here want to charge 60 - 85 bucks to set up the pump alignment. I've found the tool for 80 bucks on the net, so...... what do you think? Thanks for anyones input!

Buy the alignment tool from WWW.TransmissionPartsUSA.Com or WWW.EBay.Com. Sometimes you could get it as part of a Rotunda set. I recommend the manual valve index sleeve.

Thanks for keeping us updated. What you are finding makes sense.

Anyone have ideas on possible ways to break a stuck together clutch pack loose? Perhaps chain the truck to an unmoveable object and drive forward while the trans is in Neutral or Reverse?

You have to remove the clutch pack, and use a fine screwdriver to pry them apart.