A4LD Valve Body Questions

[Glacier991]

Now and then I get private messages (PM's) that shoud be of general interest. often they were (like this one) posted with little response. So let me post his one here, and we can start a public discussion. This was from BrooklynBay:

Hi Glacier. Congratulations! I saw that you are the new moderator on the transmission forum. I had a couple of questions that I'm sure you could answer. In the new book (volume 6) from Sonnax.com, on page 96, it lists different boost valve repair kits. It says that the 2.3, 2.8, 2.9, and 3.0 use a low ratio boost valve, and the 4.0 uses a high ratio boost valve? Does this really make a big difference depending upon the type of engine it's going onto? Wouldn't it be better to just use a high ratio boost valve to get a more responsive shift? Could that be used even on the valve bodies with the smaller engines? Another question is on the 4 different sizes of valve body balls. What determines the specifications on which size to choose? By the way, that book from Sonnax came with the October issue of Gears magazine. I also had an idea for either a new thread, diary, or as an addition to the valve body diary. Different companies make different types of reprogramming kits for different valve bodies. Could you make a thread showing the difference in the type of hardware that comes in a few different manufacturer's kits? It would be a comparison showing the different hardware from a few manufacturers showing the difference in their kits designed to fix the same specific problem. It could end off showing which kit you would recommend from that group for that problem. This is almost like a consumer reports buying guide to tranny kits! Please let me know what you think of this idea.

 

[Glacier991]

As best I know the difference is not in the VB but in the spool. Apparently the smaller engiens had a different need and a smaller boost valve worked for them.... but there was no difference in bore size. Since I always upgrade I never really analyzed it.

As to check ball size I cannot comment, other than to say they hole they fill is pretty small and I doubt there is much difference between a 1/4 inch one and a 7/32nds one.

As for the various kits, I cannot purchase very one on my own dime just to make a point, but HAVE shown the main ones that I know of.... go look again at the Valve Body rebuid dairies. Transgo and Superior are there, full contents, just as you asked.

I hope this answers your Q's. Feel free to follow up.

 

[BrooklynBay]

Thanks Glacier for answering those questions. Could you please explain which part is the spool? In the diary, it said that one of the valve body upgrades had a certain size hockey puck. By drilling out the size of the hole, it improved on the shift because of the increased fluid flow path. Wouldn't it be better to just make it as big as possible, or even eliminate it? I once spoke to somebody that used to rebuild transmissions for race cars. I know that race cars were strictly manual, but he said that he used to get some automatics in. The thing he used to do was remove the check balls completely! I was very surprised, since it would cause fluid to flow when it wasn't needed. He said that it would shift very quickly, but it would be very abrupt. It would make a very fast, hard shift, and wouldn't feel comfortable for an everyday vehicle. In my opinion, I'm sure that it would cause the U-joints, and mounts to go bad much faster than in normal use. I was also wondering why the check balls are located in different locations for different types of engines. Is this something to do with the shift pattern for different torque ratios?