I have 70,000 on a v6 3.3 2001 caravan se and the tranny started to shift hard into first at a stop light ..Checked the fluid its fine no burn smell clean..Next cel came on p0720 and now the car goes into limp mode.. Changed output sensor and cleared cel and still same problem. Replace input sensor (both factory) same problem exist.. If I clear cel tranny might drive fine for 30 minutes then start hard shifting at stop light into first...Took it to the dealer need a tranny rebuild can't tell a thing till we crack it open something is broken inside...I just drove it to the dealer without any problems till the last light before the dealer it shifted hard into first again...Help...There has to be a reasonable answer, and not break open a tranny....

 

There's lots of reasonable answers, unfortunately unless you have the Tools (real scanner) knowledge and a factory service manual with diagnostic routines, the whole thing is a total guess... just like throwing in a couple sensors and hoping for the best.

 

If I had to make a total guess I'd say it's in the valvebody. The solinoid
switch valve is hanging up.. very common problem and it won't need
the case opened to fix it.

Steve

 

Solenoid switch valve is a good 'guess' but then there's a bunch of other things it 'could' be. I highly doubt the OP would be able to repair the Solenoid switch valve.

 

For the cost of a rebuild I think it would be worth picking up a used VB and Solenoid pack. The VB is a little tricky to change from under the
van but most competant tech's should be able to do it. The sol pack
is pretty easy, just a PITA to scrape the gasket off w/o messing up the
case.

I've had great luck on E Bay with parts for this trans, very happy with the
price and the parts.

 

The hardest part of the VB is the 2 accumulators and springs. I use a dab of Petrolatum (vasoline) to hold them in place while installing the valve body. it's also CRUCIAL to torque all the bolts to 105 in lbs. However that code given has nothing to do with Solenoid switch valve. this code is related to output speed sensor, but if that was a problem, then the speedo wouldnt work either. Again, it's all speculation without the right tools to diagnose. Say you went to the doctor and without doing and testing, they said you have cancer... Wouldn't you want some proper testing done to be sure?

 

You can get codes from unrelated things, the sensor may see the hard
2-1 shift and set the light...I'd be sure the conncetor pins are nice and
tight.

Still the trans sounds heathy, I would at least get another shop to take a look at it before dropping the money for a rebuild. If it were mine and I
didn't have the tools to check it I would start with the solinoid pack
(they will replace on a rebuild anyway) then a used valvebody.

As far as the VB swap, I use a peice of radio backstrap and one of the pan bolts to hold the accumlaters and springs in place. Once the VB is close to seating just slide the backstrap out.

 

Solenoid has only one "i". Don't start just randomly throwing parts at it. It's totally obvious that hasn't worked from the start. What if the problem is in the TCM?

 

Things he can do w/o opening up the trans:

SolEnoid pack, Valvebody, TCM. These are also things that are known
to fail on a regular basis.

 

I have never had a valve body fail and only a couple solenoids ever fail but none of the new design the 01 van has. The ONLY reasonable answer is to do proper diagnosis with pressure gauges, a scanner, and a quality service manual (FSM is BEST)