[V8] 1990 V8 auto transmission issue

[Bill Braden]

Tony,

 

Thank you for the advice.

 

Actually, the harness that was replaced was the external one. The internal
harness checked out okay.

 

At this point I will get the car back to the mechanic and have him check the
codes.

 

I am located in the Florida Keys about 25 miles from Key West. Finding
anyone down here that knows anything about these cars is a real challenge.

 

If I ever get this sorted out, I will let you know how it was resolved.

 

Bill

 

 

 

From: Tony and Lillie [mailto:tonyandlillie1 at earthlink.net] 
Sent: Tuesday, June 12, 2012 7:24 AM
To: Bill Braden; V8 at audifans.com
Subject: Re: [V8] 1990 V8 auto transmission issue

 

Solonoid failure is somewhat rare, but far from unheard of in these
transmissions. The multifunction sensor will cause problems immediately when
the car is pluued from park. When they get bad enough, the car will even
remain in limp mode upon startup. So, no, that does not sound like your
issue.

 

I unfortunately do not have any direct experience with that, but would be
ohming out the harness if it were in my shop. There is a harness that is
internal in the trans (the one I suspect was replaced) and one from the
trans to the TCU. Beyond that it's going to be either a TCU failure or an
internal trans issue (I suspect this one). If that is the case, you are
either looking at sourcing a used replacement, having yours rebuilt, or
converting the car to a manual transmission.

 

Keep us updated, and BTW, where are you located?

 

HTH,

Tony

----- Original Message ----- 

Subject: [V8] 1990 V8 auto transmission issue

 

Tony,

 

I have a 1990 V8 (110K miles) that shifts down to limp mode at about 2K RPM
if you let up on the accelerator.  

 

According to the mechanic the code was a trans solenoid failure.  He checked
with ZF and apparently was told that solenoid failure is very rare and that
it was likely a wiring harness problem.

 

The pan was dropped and the solenoid positions were changed and the external
wiring harness was replaced with another used one.  The problem still
exists.  I haven't yet taken it back in to see what the code is now.

 

Am I on the right track or should I be looking at the multifunction sensor
per your comments below?

 

I love this car and it runs great other than the downshift problem.  I just
had the entire rear suspension redone (re-bushed, shocks, & brakes) and new
front brakes with new UFO rotors so I would hate to bail at this point.

 

Thanks.

 

Bill