list of common A4LD problems?

I've found a used A4LD in a running but 'bad engined' 1993 Explorer. I want to take this for a test drive this evening; its supposed to run good enough for a test drive. If the transmission seems okay I will probably buy the whole thing and drive it home; it has ALL of the various missing parts that I've been looking for on my 1991 and an extra pair of cylinder heads wouldn't hurt, either. I've read about the reverse delay and the various shift flares common in the A4LD (usually valve body and/or low-reverse servo seal related) but I'm sure that there are other common problems I have not yet read about. Of course, there is always the "always in a forward gear" problem, too, but I gather that that's not very common.

Could someone post a list of the most common problems of the A4LD in order of frequency and whether each problem can be fixed externally or requires a tear-down?

I want such a list in hand when I'm test driving so I will have an idea on the significance of the repair. I know that I'm asking a lot but I don't want to buy a used transmission, bring it home, then find out that its one and only problem requires opening up the transmission (which as I've mentioned before, I cannot do until this autumn).

Thanks in advance to anyone with the time for this.

I don't know if you've ever opened them up, but one thing that seems common in a few that I've opened up was a lot of severe wear on the rear thrust washer where the one way sprag is located. There was a lot of talk about the overdrive planetary being a fragile part. They updated them to a 6 pinion gear, and on some of them even made a one piece type with no welded seams. I don't know how that is possible, but they are made. One thing that is a little tricky when rebuilding one is installing the center support without ripping the seals. In the rebuild diary, Glacier put it into his refrigerator to make it contract in order for it to fit easier. The governor gets stuck when there is a dirt build up, and shows it when it is cold (1-2 delayed shift). The bands aren't very thick compared to some of the older transmissions. Glacier had a picture of it with a comparison side by side. He also has an A4LD planetary next to a 4R70W planetary in some thread. He said that it was not a fair comparison. The newer A4LDs had upgrades to beef it up, like torrington bearings. The Frankentranny is a perfect example of what could be done to strengthen it up. Another thing to check on a used transmission is the modulator's vacuum hose for ATF.

Bought X no. 2 a few hours ago (1993 EB 4WD). I drove it around the neighborhood for about 20 minutes and could not find anything obvious wrong with the transmission. Reverse goes clunk a bit when it engages but there is very little delay.

Yeah! I have a transmission now that works albeit in the wrong vehicle. Got a beautiful set of factory wheels out of the deal, too all for a bit less than a used transmission (with a warranty) would have cost.

I will do a photo diary of the A4LD removal and installation process as I have not yet seen that done on this list. I will post all of my photo journals when I've finished swapping the transmissions; first things first. Between twiddling with my road race bikes and getting X no. 1 to move, no time to post.

I will also be parting out X no. 2 in a few weeks and will post that on the for sale list. Do not ask what parts are available here; I will not respond to that in the transmission forum.

I'm looking forward to seeing that photo thread. You might get an elite membership for it. I could use a few parts too. Let me know when you are ready.

The Explorer that you just bought is a 93. You have a 91. Maybe you could fix it up, and use your vehicle for parts, instead of the other way around.

You're first in line. I just posted a query on the stock 1st gen list about how prices are set for parted out vehicles; that's always been a bit of a mystery to me. I know what the local "you pull it" place charges and I know the value of BMW car parts and early Honda motorcycle parts, but I'm kind of clueless on what X parts sell for. http://www.explorerforum.com/forums/showthread.php?t=158180

I have material now for a supplement to the valve body rebuild diaries (both of them). I also have material for a "proper jacking and jack stand points" thread. Will be doing one on radius arm bushing replacement via the rivet grinding method; there is good text on this and an off list photo set (w/ HUGE photos) but nothing combining the two.

Too many race weekends back to back, not much time to do anything else.

BrooklynBay said:

The Explorer that you just bought is an 93. You have a 91. Maybe you could fix it up, and use your vehicle for parts, instead of the other way around.

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The 1993 is green (not my fav. color), has no sunroof, or tilt st. wheel - all kind of hard to change. Plus the motor has a bad rod knock. The 1991 has everything except a functional A4LD, LSD rear end or leather seats (or the Ltd. fog lights in the front valence). I forgot to look, the 1993 might have an LSD rear end, that would be WAY cool; I would swap that in a heartbeat. The 1993 does have electric seats in the correct color for the 1991 but they are pretty beat. Not sure if I want to swap those yet. The seats in my 1991 are flawless but not very adjustable. (not bad for a $500 car (the 1991)). Still thinking; thus my comment that I'm not listing it for a parts car yet. Not sure what I want to keep.

I've also started perfecting the 1991 to my standards; it would be a shame to start that over again on another one. Already replaced most all of the coolant and vacuum hoses, brakes, and lots of the suspension. Have a few door seals to do but that's about all I've found wrong with the 1991 (w/o having driven it more than 10 miles).

You might want to save parts like the PCM, GEM, and some other stuff just in case. Just check to see if they are compatible, or you will have parts sitting around with no use.

I was thinking of keeping the heads and the ECU (that's a bmw term, not sure what ford calls the main computer). The PCM?

I will look through the "Old Explorers" parts replacement thread again; that thread might indicate what parts I should keep as extras.