Caravan 604 nightmare
 

My '89 Caravan 3L with 604 trans has been apart 3 times, had all the
upgrades installed, so I'm just about positive that there's nothing
internally wrong with it.
However, it keeps going into limp-in mode at seemingly random times.
The local tranny shop wants $50 to retrive trans fault codes, which
I'll probably do if I have to.
I have a donor engine that I can rob sensors off of to see if that
will correct the problem.
My question: Which engine sensors are used as input to control
transmission? I know the TPS is, as well as the coolant temp sensor,
but any others?

James Goforth wrote:
> My '89 Caravan 3L with 604 trans has been apart 3 times, had all the
> upgrades installed, so I'm just about positive that there's nothing
> internally wrong with it.
> However, it keeps going into limp-in mode at seemingly random times.
> The local tranny shop wants $50 to retrive trans fault codes, which
> I'll probably do if I have to.
> I have a donor engine that I can rob sensors off of to see if that
> will correct the problem.
> My question: Which engine sensors are used as input to control
> transmission? I know the TPS is, as well as the coolant temp sensor,
> but any others?
>
You've got to get the codes pulled. The TCM will tell you what's putting
it in "limp-in". Could be a speed sensor, a bad connection, or...?

"James Goforth" > wrote in message
...
> My '89 Caravan 3L with 604 trans has been apart 3 times, had all the
> upgrades installed, so I'm just about positive that there's nothing
> internally wrong with it.
> However, it keeps going into limp-in mode at seemingly random times.
> The local tranny shop wants $50 to retrive trans fault codes, which
> I'll probably do if I have to.
> I have a donor engine that I can rob sensors off of to see if that
> will correct the problem.
> My question: Which engine sensors are used as input to control
> transmission? I know the TPS is, as well as the coolant temp sensor,
> but any others?
>

I personally would save the $50 unless you think it is internal to the
transmission. Try these for corrective measures in order:
1. Make sure you've got the correct fluid in there
2. Change the input/output speed sensors.
4. Change crank and camshaft position sensors.
5. Change PRNDLE switch.
3. Then I'd probably try the ECM.