A343F Transmission Rebuild - Valve Body Questions (1 Viewer)

[Gerrha]

Sometimes I tend to overthink things, but this is kind of weird. I am doing a complete rebuild of the A343F transmission from my 97. I have a full Transtar kit for this and I also bought a Transgo valve reprogramming kit to install at the same time. I decided to start with the valve body and painstakingly took it apart taking multiple photos along the way.

The upper valve body has 8 rubber balls scattered around in various locations. I confirmed this with the number of balls in my parts container, my photos, the FSM, and various online parts diagrams.

Weird Thing-1: The situation with the lower valve body gets murky. My photos and my parts container confirm that there is only one rubber ball in my lower valve body. The weird thing is that the FSM shows there are two rubber balls, and the online parts diagrams show there are no rubber balls at all in the lower valve body.

Weird Thing-2: The Transgo valve reprogramming kit instructions say to remove all balls in the lower valve body and several more in the upper valve body.

My question is about these rubber balls. I am guessing they function like a check valve and surely, they have some real function in the operation of the transmission. Can someone please enlighten me regarding this?

 

[Kernal]

There was a TSB (Technical Service Bulletin) many years ago addressing an issue about shudder with the A343F transmission and discussed the location of the balls (see link and TSB below). There were some running changes to the valve body depending on the Serial Number. But also try a search for Transgo+valve+body in this forum as others have installed that kit.

Here's one old discussion:

A343F reverse noise

It's a '95 FZJ80 with the A343F, 93,000 miles. Recent tranny flush a few months ago. What happens is when I put it into reverse and there's a load, such as trying to back up a hill or over something, the engine revs, the rig doesn't move and then a noise that sounds like metal grinding or...

forum.ih8mud.com

Here is the TSB from that thread:

 

[Gerrha]

Thanks, I really appreciate that information. I read through all of it, and I am very lucky to have discovered that my transmission has had all of the TSB changes made to it, so I am good to go with that part at least.

Based on previous discussions, I have also decided against the Transgo reprogramming kit. One of the posters in a previous discussion said that installing this kit would likely breathe life into a tired and worn transmission. But he added, if you install the kit and then down the road rebuild the transmission, the changes made by the kit likely would become detrimental with much too harsh shifting etc. That makes sense to me. This kit instructs to remove 2 balls in the upper valve body, all balls in the lower valve body, and enlarge 4 holes in the separator plate. I am going to wait on that. It can be done fairly easily later if I decide it is needed.

However, I still have a question regarding the lower valve body. In mine, there is one ball only and the FSM shows two balls. If I knew exactly what the heck those two balls did, then maybe I could figure it out.