I picked up an 03 Outback and the Front diff had gone south.  Some teeth were completely gone.  The PO had had the trans rebuilt by AMMCO 4 years prior and said it just stopped.  It had been running fine up to that point.  

 

It would drive but every time it came to the missing tooth it jumped like crazy, Only drove it on to the flatbed.  

 

I replace the trans with a used one.  They had the same trans number and it drove and shifted well but then started very hard shift changes when you accelerated hard. - Slow steady driving it still shifts well up and down.

- If I manually shift the trans it shifts well without any shock

- If I get on the gas in pretty much any gear, the engine RPM goes up and then after a second it drops into gear.  Hard enough that it feels like someone just hit the car in the rear.

 

I disconnected the battery and left it off for a couple of hours.  This seemed to reset the TCU and it shifted well for about 5 miles and then started the hard shifts again.

 

The fluid was clean and I did flush it and change the filter

The FWD fuse works fine, the hard shifting happens when it's in FWD as well.

 

Any Ideas?

 

Thanks

The TPS out of adjustment will produce this. 

Is this a temperature related issue? Once it starts, if you let it sit over night and cool does it still shift hard the next morning?

Happens hot or cold.  

Going after the O2 sensor fault first and then the trans.  

 

I do have the other trans for parts, but don't want to just throw parts at it.  

 

If the TPS is correctly set and everything else checks out I'll take it to a trans shop and have them hook up to the computer.

I took it to a quality trans shop today.  With the scanner on they could see the trans shift into neutral and then back into gear. 

 

I'm going to check the Inhibitor switch as I'm thinking the TCU may be seeing the trans shift to neutral and then back into gear under high revs if things move enough.  

 

This would make sense as the trans shifts well if I keep the RPM in the 2-3K range or if I manually shift the trans! 

Might just make sure the cable is adjusted properly before replacing the switch.

Trans wasn't out of an '04, was it?

No I believe it was an 02 Forester.  The trans had the same number so it should  be a direct plug  and play.

 

I believe I have it solved, the Inhibitor switch was slightly off.  I rotated it  about an 1/8" clockwise and the short test drive was good.  

 

Additional road time will confirm the fix.  

 

When the shop saw the trans shift to neutral and then come back into gear and with the trans shifting well in the manual mode I saw the light!

 

Thanks for the Help.

Larry

Better but not fixed.  The shifting is on as hard and it now shifts well up to 4K.  I think I may have found the problem.  

 

The Inhibitor that is on the trans I installed has 4 mounting bolts.  

The Inhibitor that is on the original trans has 3 mounting bolts so there may be some difference.

 

I thought the transmission numbers were the same, but there may be some differences.

 

Trans Experts, any ideas?

 

Can I find the correct ECU and swap it in or do I need to swap the trans? 

woah, weird. 

 

the trans pan isn't damaged at all is it?  i picked up a trans and the pan was damaged.  it was damaged so slightly that i actually wouldn't have noticed had the previous owner not told me.  it didn't seem damaged, though he said he did try to repair the pan on the vehicle.  he said it would drive but wouldn't shift correctly. when i pulled the pan 3 of the solenoids had tabs where the wiring harness connects cracked.  should have an AT light if that's the case i would think though. i'm going to swap those 3 solenoids, another pan, and see how this transmission does.

 

TCU?  with no AT light flashing and it shifted fine sometimes, it seems like it has a small chance of working.

Don't these have some kind of resistor block on the strut tower that affects the way the trans shifts?

 

As far as I know if it plugs in it should be fine, but there was a change in 04 with the way the C duty solenoid works, so I guess its entirely possible they changed some other things too.

Yes no flashing AT light.

Pan was not dented

Good Clean Fluid

Shifts fine if I keep the RPM low

Shifts fine if I manually shift gears

 

I'm going to try to find a TCU from a trans with the newer inhibitor switch and see if that does not take care of the problem, but that will not be for a few weeks.  Darn work is getting in the way of Subaru fun.