TRNW-2: 6r140 valve body and sonnax tooling

[William Chechel]

I have not seen  too many of these for one reason or another. The last
three that I did I just went with the valve body as is and had no problems.
I think the 4-5-6 wears outs and another thing we are seeing is overheating
issues. Maybe I just got lucky, or maybe this trans doesn't warrant a shift
kit.

There are two cooling systems on these trucks. The turbo and transmission
share a separate coolant fill and reservoir. The last two I had the owners
killed the trans by towing with the trans running hot. They had not idea it
was an external problem of the trans causing the overheat. We had to
rebuilt the unit but also had to address the coolant leaks.

I am interested to see what everyone else is doing on these.





On Wed, Dec 31, 2025 at 6:47 AM Fred Whitaker via trnw2 <trnw2 at trnw.net>
wrote:

>   Just a "Bump" for Justin. I too am wondering if anyone has a better
> Mouse trap. I have fixed a number of these by just slapping on a Ford valve
> body ,never really looking into just what might be causing problems. I have
> always leaned towards blaming solenoids with no proof.
>  Looks like Transgo still has nothing. Not much to the Sonnax Zip kit. I
> have my doubts about their Oringed end plugs they seem to put in EVERY Zip
> Kit.
> ------------------------------
> *From:* trnw2-bounces at trnw.net <trnw2-bounces at trnw.net> on behalf of
> Justin Merritt via trnw2 <trnw2 at trnw.net>
> *Sent:* Tuesday, December 30, 2025 1:45 PM
> *To:* Technical Discussion Forum <trnw2 at trnw.net>
> *Subject:* TRNW-2: 6r140 valve body and sonnax tooling
>
> Hello all,
> I am starting to see more and more 6r140s hit my bench.  I am comfortable
> with working on them with great success.  I have always just replaced the
> valve body with a ford OEM, but it seems these valve bodys are getting
> priced to where I may need to look at repairing them vs replacing them.  I
> do not mind investing in sonnax tooling that is needed to fix
> transmissions.  However, I don't believe in needing to ream and oversize
> every valve just because there is something available.  What are the high
> wear areas that will need to be addressed if I decide to tool up and repair
> these valve bodys?
>
> Thanks Justin
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-- 
Bill Chechel
Cell# 484-241-1072
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