A4LD tranny clarifications please

[Glacier991]

I agree with Opera House's Q. Also what does the inside of the bore look like? Sonnax has a kit that has you shave down the servo a little and adds some sealing. If the servo itself and it's bore are not the problem, move upstream hydraulically. Valve Body. Good call OH.

 

[have2goski]

Opera......not sure exactly which things you are talking about off the top of my head. I left my book on the tranny up in cleveland with the explorer so technical terms escape me right now

the bore and the low/reverse piston seemed to be in excelent shape. no dings or scratches that i could see.

i also forgot to mention that the vacuum modulator was replaced also. I had read a few threads where people speculated about it and figured it was a cheap enough part i could get to with the tranny in

the tranny is very clean. I didn't have any pieces of metal down in the pan or anything like that. I run an aux filter and 2 stock aux coolers up front. change the filter every 3000 miles when i change the oil

i think it is a hydraulic flow problem rather than a mechanical failure/wear problem. I just don't know where to go with it.

I thought about taking it into a shop and having them simply remove and reinstall the valvebody with new gaskets for me. Maybe i have something in there not quite right and just don't know it from lack of expereince

 

[Opera House]

It is not just the bore wall but how the keepers might be installed or missing. The kickdown ocupies the same bore. Maybe Glacier can put up a picture of the hockey pucks and where they go. Not sure how they relate to the problem, but if you ever saw one you would remember it. Thet are tiny flat plastic disks. They would stick in your mind because you would realize how easy they are to overlook. I only found mine when I looked through the sediment of the washout. The ATSG manual is terrible on this deatail.

 

[have2goski]

a picture would be worth a thousand words if somebody has one

I also saw in glacier's thread that he is going with the .015 thick gaskets opposed to the standard .009 thick ones for the valve body. any reason for doing this?


thanks

 

[msmith65]

I re-did my servo o/D-rings this weekend. I bought the seals and gasket at Transtar (Grand Prairie, Texas, 972-642-7575, www.transtar.com) individually so I didn't have to buy the whole rebuild kit.

Transtar's part numbers are K3435L (improved D-ring seals) and 13708 (servo cover gasket). They also have the filter and pan gasket if you need those; I don't know if their filter is the improved type as opposed to the screen.

We were having infrequent failures to go from R to D (RPMs rose but the car wouldn't move for a minute or two), and a rarer failure to accelerate from a standing stop within a few minutes of backing up. The vehicle runs fine after the replacement, as it did 99 percent of the time beforehand, so I guess we'll have to wait for cold weather to see if the problem is gone.

I did not see any obviously failed/failing parts while I was in there. The O-rings looked fine. I do not know what causes the failure mode of this servo. There were four small metal irregularities on the rim of the larger, lower disc part of the servo, corresponding with openings in the servo housing. Hard to imagine this was enough to hang up the servo, but I took the roughness off with a sanding sponge anyway. The metal is softer than you might think, so sand conservatively and use fluid to cushion the movement.

Here is one DAMHIK if you're planning to do this yourself: Buy two of the seal kits. They are dirt-cheap (couple of bucks, really), and if you're as clumsy as I am you may break one of them trying to get it on straight. I ended up re-using the smaller O-ring because I was working on Sunday and my wife needed the car the next day. So if the failure crops up again, I'll have a pretty good idea where to look. :-(

Also, I put a drain plug in the transmission pan while I was at it. Auto-parts stores carry them. I put it right in the middle of the pan's low point, below the filter, and it didn't foul anything upon re-installation. I guess an easy way to test that would have been to put the drain's retainer nut in the pan, hold it in place with a magnet on the outside, then put the pan in place sans gasket. Funny how I never think about these things at the time.

As a final touch I stuck a big old honkin' magnet on the outside of the pan. We'll see what it attracts.