Replace valve body on A541?

Four years ago I bought a '95 Lexus ES300 that shifted very smoothly
but had dark brown transmission fluid. I had the transmission
power-flushed on a T-Tech machine and immediately thereafter the shifts
became harsh and slightly erratic. Somebody suggested that dirt
dislodged by the flush had probably clogged/damaged the valve body.

Over the next 4 years I drained and filled the transmission a number of
times, and each time shifts would get smoother for a few days. Last
month I finally had it power flushed again, and this time there was a
significant but temporary improvement.

Does this sound like a valve body problem? If so, how hard is it to
replace (with a remanufactured unit)? Is this something that can be
done in a few hours by a non-professional without specialized tools?

Thanks,
Tripurari

> Does this sound like a valve body problem? If so, how hard is it to
> replace (with a remanufactured unit)? Is this something that can be
> done in a few hours by a non-professional without specialized tools?
>
> Thanks,
> Tripurari

It could be your valve body, but it could be other things too such as a
bad accumulator, etc. I would check your throttle pressure cable first
along with a line presure test on the trans to see what is happening to
the pressure during the stall tests and normal shifting. If it is out
of spec, then an adjustment or replacement of the throttle presure
cable could bring it back in line. You can easily do this yourself by
buying a pressure gauge kit off Ebay for $35 (Page Autosupply).

As to replacing the valve body: Yes you can do it yourself, but you
need to be mechanically experienced and meticulous because there are
many parts and steps you need to go thru to get the valve body off and
back on. It can be done, but it IS a challenge and will take you 6+
hrs the first time most likely. You will also need a ATSC trans manual
for your transmission and need to spend several hours familiarizing
yourself with the removal and installation procedures. As well, you
need an accurate torque wrench that can do in-lbs. And of course, you
should not mind having trans fluid all over you and your garage floor.


Unless you have balls and like a challenge, I would not recommend
re-building the valve body yourself. I say this because I have done it
and would not do it again. Why? There are all kinds of problems you
can run into such as the trans service manual not being up to date on
the latest changes, parts falling on the floor and getting damaged,
stuck valve plugs, wrong re-assembly or messing parts up (and there are
LOTS or parts!), stuck or bonded gaskets, etc. You can buy a reman'ed
valve body from Phoenix hard parts for around $200 with a core return
on your old one. They test it on a dedicated hydraulic VB tester to
make sure it works properly. If you go that route, be sure to call
them and ask them about the shift solenoids and whether they are also
included. If not, I would recommend a new solenoid kit also from
bulkparts online. While in there, you should also replace the o-rings
and seal on the 3 large accumulators in case one of those has a blown
ring.

cheers,

dave mc