Hi,Im going to tackle the tranny rebuild on my 91 explorer 4.0 2 WD. // A4LD // have read up on some updates as far as beefer bands and servo's and such,Im an ex master tech with ford ex. ,allthou automatic trans are new to me.. I have all the time I need,the truck is not a everyday driver, I have O.E.ford repair & service on a disc,but they only cover 1996 to 2002,and I see it covers A4LD in 1996,my question is,how much of the step by step directions on the disc can I use to build my 91 ? the internal mechanical workings maybe?? my goal is to rebuild the trans to a heavier duty condition and change my gear from a 3.07 to a 4.10 for pulling my boat ,I overheated the transmission pulling my boat,2000LBS // its toast now.. boiled the fluid out of the top vent,tried doing a professional flush,that lasted 15 miles before it overheated again,without towing... also whats your opinion on useing a A/C condenser for a trans cooler?? I also have seen a kit to replace the A4LD with a GM 700R4 to a 4.0 with the electrical for the lock up conv... but I would rather stick to the ford o.e. tranny..

 

You need a big cooler. I'm gonna look for a link that might help you...

 

I bought a plate type cooler from Summit Racing. It was made by B&M. Just use the largest one that will fit in the available space. A tranny cooler will not save you from what happened however. You were towing in OD weren't you. If you are in OD and the toque converter comes unlocked (it does this at about 65% throttle or more) and the the resulting heat can toast the fluid. The earlier A4LD models did have more problems and the upgrade parts will help a lot, and by all means get the plate cooler, but when you come up on the hills, take it out of OD. It will save the transmission from excessive stress and heat build up, and it is easier on the engine too.

 

No,I was not towing in overdrive.. have to floor it and hold it to take off and get to speed,overheated it.. I think due to the high gear Im running..

 

Ok, running a lower gear would help, what size tires do you have? The torque converter does come unlocked in third gear too, and so there is still some heat build up in 3rd, and there is no lockup in 1st or 2nd gears. So if you spend a lot of time stopping and going with a trailer, that could be hard on the transmission.

The factory bands weren't that great, so you can benefit from beefier internals.

Are you sure the thransmission wasn't low on fluid and are you sure it was coming out the overflow tube and not one of the seals? When mine puked fluid once it was coming out the front seal because the heat had baked it.

In mine, the previous owner ran it low on fluid and burned it up inside. Scorched all the seals, messed up the valve body and burnt the bands. Ended up costing me a pretty penny. The A4LD can handle a bit once it gets beefed up if you can keep the torque converter locked up. Lowering the final drive ratio will help keep the trans a bit cooler and improve your ability to haul loads.

 

THANKS FOR THE INFO,DO YOU THINK THERE IS MUCH TECH BOOK MECHANICAL DIFFERENCE BETTWEEN THE 1991 & 1996 A4LD'S??

 

There are no '96 A4LDs The last A4LDs were mid '94. After that they became the 4E44e which is the electronic version of the A4LD. The computer controls all the shifts in the newer electronic trans. The overall operation is close, most of the differences are in the valve body.

you can either rebuild your trans, find another to rebuild, get one that is already rebuilt or just take your chances with a junkyard trans. Or you can converter to a 5 speed manual trans.

 

have you looked at the rebuild diary in '99f350sd's post? Between that and the "frankentranny" thread, they discuss the similarities and differences between the A4LD and 4R55E and the 5R55E, and how to use the later transmission parts to try and improve on the A4LD.

 

There are a lot of things that are interchangeable and you can definately beef up the older A4LD with some of the newer parts. You can also just buy kits with upgraded parts and you have the benefit that they are new parts.

The main differences between the older A4LD and the newer units is that the A4LD is a hybrid hydraulic transmission with solenoids to control some features, such as torque converter lockup and overdrive. But the other shifts are still controlled by fluid pressures and mechanical governers, vacuum modulators, and a kickdown cable. The newer units shift when the computer tells them to, so they have more electronic controls. Most of these changes occur within the valve body itself, so many of the other parts are identical or at least interchangable with the older parts. Some of them are considered to be upgrades since they may be stronger or by some other virtue, more durable.

So you can certainly use parts from a newer trans to rebuild or beef up an older trans, but no, you cannot simply swap a newer one into the older vehicle without also swapping over a lot of electronics and anything else that that requires.

 

I am going to rebuild my trans in my 99 and when doing so I am adding a second transmission cooler. I dont know if they are the same, but the 99 era explorer and rangers are simply hoses with ring clamps on them. I picked one up off a junkyard ranger and am just going to add it in series on the other side of the grill. Could probably do that fairly easy and cheap to try to help the heat.