Shift Pointers
- Subject: Differences in manual valves
- Unit: Toyota A340F, Honda MDKA
- Vehicle Applications: 2002 Toyota Sequoia, 2003 Acura MDX
- Essential Reading: Rebuilder, Diagnostician
- Author: Pete Luban, ATSG
A while back one of our members called the tech line about a 2002 Toyota Sequoia that required replacement of the valve body. After the valve body was installed the vehicle had no reverse, pulled forward in neutral but drove perfectly when the selector lever was in the overdrive position.
Because this particular problem did not exist with the original valve body, logic would dictate that this replacement valve body had to be the cause. Well, after some deliberation it was decided that maybe the problem was in the manual-valve area. Another valve body was pulled from stock and the technician noticed that this manual valve was different, even though the two valve bodies appeared exactly the same. The technician decided to switch the two manual valves, and guess what: The problem was gone and the transmission performed just as it should.
What you see in Figure 1 are two different valves with very different dimensions. Note that the valve at the top of the photo came from a valve body with a casting number of 8932 and the bottom valve came from a valve body with a casting number of 8938.
The chart in Figure 2 gives you the valve measurements; as you can see the differences are not obvious at a glance but closer inspection shows otherwise.
While we are on the subject of manual valves here is an interchange problem that ATSG’s José Garcia ran into. A 2003 Acura MDX with an MDKA transmission had some valve-body problems that required replacement of the valve body.
The replacement valve body had the same casting number as the original, but when the transmission was road-tested gears one through five were fine but there was no reverse. A careful inspection of the valve-body components found a difference in the secondary valve body and the manual valve. In checking with the supplier, the shop discovered that this valve body actually came out of a Saturn Vue with an MDPA transmission. One of the manual-valve spools had a difference of 0.025 inch, and that and the spacer plate were causing the no-reverse condition.
At this point we all are aware that Acura and Honda are the experts when it comes to subtle differences; here was a good example of exactly that. Be careful out there.
