Hello, I am a newbie. I own a replica 1955 Porsche 356 powered by a mid engine 2001 2.5 Forester and 4EAT.  Car runs great, and shifts fine while in drive, but I can not manually downshift to any lower gears. Whatever  lower gear the selector is   placed in the car acts as if in drive.  This problem was intermittent at first, now happens all the time. I have replaced the inhibiter switch, drained and replaced both filters, new fluid, checked all solenoids, and shifting linkage.  I even tried different TCU and ECU.  Car runs great in drive, shifts up and down as it should, but still I am not able to manually use any lower gear.

I have contacted several local shops but the problem can not be pin pointed. At first the only codes pulled pointed to the inhibiter switch, but now I can not pull any trouble codes at all.  Anybody out there recognize this problem?

That sounds like limp mode, you get 3rd and reverse.

 

Often an electrical problem between the trans and the TCU and power/gnd.

 

(subaru powered porsche? you gotta post pics!)

Thanks for response.  To clarify, ALL forward gears  work fine when selector is in drive. Reverse works fine when selector is in reverse. When selector is placed in any other forward gear car still acts as if in drive.  When selector is in drive and you manually  shift to a lower gear there is no  gear change. This is Not limp mode.

I would guess a valve body issue.

Putting the selector in 1 should hold the trans to first gear only. IIRC It's based on the position of the manual spool valve.

 

Do you know any history of the trans? Where did it come from? Has it ever been worked on?

Have you connected a light to the output from the TCU that indicates the trans is overheating, to see if it's flashing?

 

Maybe it's 'smart' enough to look for a mis-compare between the electrical switch and the valve body sensors? (If it even has such)

 

When you drive in D and slow down or floor it, does it downshift?

 

No dents, even slight, in the pan?

 

Spin-on filter remoted?

Sorry , I have limited info on engine & trans.  Car was built by someone else in 2007 , supposedly  using a low mileage 2001 forester with 4eat out of same car.  I was driving this car sparingly for a few months before this problem began , intermittently at first, now all the time.  I am beginning to think my car originally had a manual shift mode switch which was disabled somehow to be permanently on , and now is not functioning .  I am also actively trying to confirm with the builder what exactly was used in the build.   Still looking for answers.

Trans is not overheating,  no dents in pan, trans shifts up and down just fine with selector in D when accelerating or decelerating,

Well after months of being told by the builder of this car my engine and trans was from a 2001 Forester, it turns out after being given the donor cars VIN it is actually a 2001 Outback.  Sorry to start out on the wrong foot. But I was only going by what info I had. Regardless, if anyone out there  can help I would be grateful.  Thanks

It does not matter, the trans is the same between them. Or close enough that it will not matter. Subaru DID have a sport shift mode in Japan. As far as I know it's a TCU function. It's doubtful that's your issue, but you could try another TCU. 2000-2002 Outback/ Forester should work

I have tried 3 different TCU 's.  Same condition on all three. 

It has to be the transmission then. A weird failure. When you put selectors in anything but drive, it holds the gears differently than in drive.

Well my mystery continues.  Today I started the car and removed the harness from the inhibitor switch. I expected either a  limp mode ,( reverse & 3rd) or all gears working by manually shifting.  Well to my surprise I have park, reverse, neutral, and drive.  Car upshifts and downshifts automatically through all gears weather the selector is in drive or any lower gear position. This is driving me nuts.  I could live with this condition if I was a flatlander, but here in Colorado it would be nice to be able to manually downshift in the mountains and not have to ride the brake.   "ANYBODY" out there heard of this one before?

Unplugging the main harness for the trans puts it in limp mode.

 

Actually thinking about that, unplugging the inhibitor switch doesn't really change much other than you can't start the engine, but IIRC there is a signal from the inhibitor switch to that tells the cluster which gear light to turn on when the selector is moved to each position. (p,r,n,d etc.)

Do you have those lights in your current instrument cluster?

I don't remember off hand, but that may also signal the TCU to change down or up based on selector position. If you don't have those lights, the circuit for them has to be wired in some manner, it's possible that circuit has a poor connection or is not getting correct voltage from its supply.

Edited November 25, 20178 yr by Fairtax4me

No , I do not have the original instrument cluster or any gear lights at all. Please forgive my ignorance , but what is IIrc

I just answered my own stupid question, about (IIRC) If I Remember Correctly.  Getting old and not keeping up with things is hard.

Problem Solved.  And the winner is.......Soobero... Well at least he was the closest in solving the problem  (poor connection) which was a bad ground. I found a ground which had a butt connector wrapped up in the wiring harness that was bad.  Sometimes made contact, usually not.   Car runs great and everything working as it should.  Thanks to all for your help.   Paul

Good to hear it was a simple fix.