94 explorer A4LD RPM jump between 2nd and 3rd

[DeadlySteve]

Hello Everyone!

I want to preface this by saying I understand that a used A4LD transmission is a failure surrounded by a nightmare wrapped in a leaky box filled with problems.

I have a 94 explorer (with 142k miles) that I purchased for next to nothing with a lot of problems. 1 week after purchasing it, the torque converter blew up and trashed the transmission.

I was given another parts explorer for free (with 144k miles) and a functional transmission. I stripped them down to the frames and between the two explorers, I've pieced together an almost flawless 94 explorer that everyone seems to be pretty impressed with for some reason (if that's possible lol).

Anyway... I cleaned out all the trans lines, swapped in the transmission and put in a new torque converter. Drained all the fluid and filled it. Put in a new filter.

This new transmission does work fine... however, if you accelerate slowly; when it goes to shift into 3rd gear, the RPM's jump about 1k for about a second and then it shifts into gear.

If you accelerate faster than normal (how I want to drive... lol) it has no jumps at all.

It drives around fine... no big deal... I'm just curious. I'm currently looking for an M5OD donor explorer to do a manual swap with. I miss having a stick shift!!

I should also note that I don't actually know how most of the transmission works. I'm a DIY / take things apart / read how-to's / type of person. I don't have mechanical knowledge of how half the parts in a vehicle work... but if I can find what needs to be replaced or if you tell me; I can do it every time.

Any help would be VERY appreciated... even if its, "Hey! you're transmission sucks. Find a new one!!" lol

Thank you very much. :-D

 

[wood1]

Hey Steve, welcome to the site. Nice Limited you have there.

I would first adjust the bands and the kick-down linkage. Likely you have done the kickdown already. There are threads in the transmission section. That may help with the flare and are very quick and easy to do.

If that does not help it could be the vacuum modulator which is accessible from inside of the vehicle through the plate in the center of the floor where the manual shifter would be if you had a 5 sp. It is on the passenger side of the transmission. I did mine that way and it took about an hour.

If that does not work I would replace the intermediate servo, you might have a cut (or it is hardened and leaking). The servos reside behind the heat shield on the passenger side close to the vacuum modulator. The heat shield is actually there to protect the servos from getting baked by the heat of the exhaust, thus preventing them from hardening, shrinking, leaking...

Lastly, if that doesn't work you can rebuild your valve body. If you feel capable rebuilding it is about a 6 out of 10 on the scale for difficulty. There is a very good thread by Glacier on rebuilding it that I followed when I did mine. There are many improvements that you do while rebuilding it that make it shift firmer and improve the life expectancy of the transmission. The ATSG manual calls for you to remove and clean the VB for a 2-3 flare. VB malfunctions are usually caused by that black sediment type stuff that collects in the pan. I would say that if you are going to pull it out to clean it and check the free movement of the valves, you might as well either replace it with a rebuilt (Central valve Bodies) or rebuild it yourself. That black crap can cause the valves to jamb. You never know, the problem could be caused by a blown out VB gasket too. If there is a small leak internally it could cause your flare. Oh, Central rebuilds and installs the improvements you would do following Glacier's thread. They test them too. It probably sounds like I work for Central but I have no affiliation. I just think they are a good choice if you don't want to tackle the job yourself.

I installed a Fram Dacron filter to catch that sediment crap (far better filter than those cheap screens you usually get), as well as a home made external filter set-up to further protect my nice clean rebuilt VB from that gunk. I used a hydraulic filter head and piped it into the tranny cooler plumbing. It uses a common oil filter that is easy to change. That external filter also prevents that crap from screwing up the governor which is also very sensitive to the sediment type black stuff.

Oh, if you are going to keep the automatic add a big tranny cooler to the one you have. These transmissions run warm and that reduces their life (a great reason to only use synthetic fluid). Hook it up in series to the one you have, make sure you never mount a tranny cooler with the connections on the bottom, they will air lock that way.

I guess that's it, if you are going to change to the 5sp, just adjust the bands and the kickdown. You could change the modulator as it's cheap and easy to do too. I would probably not go any further depending on how long you plan to run the automatic. If you want a copy of the ATSG manual for the A4LD send me a PM with your email.

I did all that stuff to my transmission and it has been working more or less well since. Shifts quick and firm, has 322000 kms on it and still going strong.

Wood.

 

[DeadlySteve]

Thank you for your awesome reply Wood! Most of those potential fixes don't seem very hard at all.

Looks like I've got some work to do. I'll come back on here with what I find! ^_^