Rebuild 89 Caravan -- 3-speed or 4-speed tranny?

Hi, gang:

I'm rebuilding my 89 Grand Caravan (don't laugh! I love the thing, and
the old-timer I bought it from 4 years ago paid almost $2000 to
rustproof the chassis -- a huge advantage here in salt-the-roads
Minnesota). Besides, I have a second 89 Caravan for parts

Anyway, the chassis and running gear are in excellent shape, but the
engine and the second 4-speed tranny are coming close to the
200,000-mile mark. It runs okay, but it's been sounding like crap for
more than a year. (It drives very nicely, however, with smooth
suspension, tight steering and all possible options. It's a power
marshmallow!)

I can have the engine and tranny rebuilt for about $2000, and I can
handle the paint and minor body work myself. With what new (or newer)
vehicles cost these days, I just don't wanna invest...

My question is about the tranny. I have two 4-speed overdrives which,
according to anecdotal and personal evidence, are fairly unreliable.
And I have one 3-speed tranny from an 89 Plymouth Voyager.

Will the three-speed fit?

Should it be more reliable than the 4-speeds? (Especially when
pulling my fishing boat or pop-up camper trailer?)

Do I need to change the front axles or anything else to make it fit?

Is this a good idea?


Thanks in advance,

--Kirk in Minnesota

 

Which engine do you have? Which engine was attached to the "donor" 3-speed
you have? The 3-speed bell housing changed when the starter (on the 2.2L0
was changed from direct drive to gear reduction. Then there was the
difference in torque converters when the cranks were changed in the
production of the 2.2L. I don't know which engine you have so am just
using the 2.2 differences as something to remember. I don't know if a
different tranny was used in a Turbo engine as compared to a normally
asphirated (spelling??) one either.

It is not as easy to asnwer as you might think. My mechanic suggested that
one way is to find the "number" of the 3-speed you have on the vehicle now
and the number of the 3-speed donor transmission and use a Hollander
manual to see if they can be interchanged.

This is a timely question because the 3-speed in my '84 has just started
shifting problems - due to one of the diff bearings starting to fail and
the little chips are getting into the governor causing shift problems.
Solution is a complete rebuild (tranny has about 270,000 km and is
probably original) and a rebuilt torque converter AND flushing the oil
cooler + hoses.

See above.

The 3-speed is reputed to be MORE reliable than the plagued 4-speed. I
seldom read about 3-speed problems but read about a lot of 4-speed
failures.

Ken in Manitoba

 

Ooops!

All vehicles (runners, parts trucks and tranny donors) have 3.0 L engines.

Is switching to the three-speed a real hassle?

--Kirk

re:

 

Related Question:

Can anything be done during the rebuild to INCREASE the reliability of
the 1989 Caravan 4-speed tranny? Or are these things simply doomed?

Perhaps I should rebuild BOTH 4-speed units so I can swap them in and
out every 25,000 miles? Ouch!

Thanks, as usual,

--Kirk

re:

 

Certainly!

1) Install a later transmission control computer, e.g. from a '95 or so.
Mechanically and electrically they swap right on, and the programming is
much, much "friendlier" to the hardware. The later computers are
identified by a finned case rather than a smooth/unfinned one, and they
can be "flashed" (updated with new firmware), which the older ones cannot.

2) Obtain the transmission from a very-late-model (current production)
wreck and swap the guts complete into your '89 case.

OR

3) Dispense with the A604 altogether and build and swap-in an A670 3-speed
auto.

DS

 

"Different" in that it had more clutch plates, different final drive ratio
and (through '90) a non-lockup torque converter, yes, but they are
physically interchangeable. Not sure why we're discussing 4-cylinder
engines and direct-drive starters, though -- the OP has a V6 van.

It is exactly as easy to answer as he might think: Yes, an A670 3-speed
automatic will go directly in place of an A604 4-speed automatic behind a
3.0 V6. A different gearshift cable is required, and of course the
kickdown cable must be installed, and there are other minor adaptations,
but beyonr that, no difficulty will be encountered.

Doesn't sound as if your mechanic has much experience with Hollander
manuals. They inform you what parts are physically and functionally
identical -- they do NOT give information like "The 3-speed auto will fit
in place of the 4-speed if you install a different shift cable and put in
a kickdown cable and..." etc.

DS

 

Or you could take a little road trip down to Ventura, CA and pick up the
nice-running/nice-shifting 67k-mile 3.0/604 that are coming out of my '92
Spirit to make way for a 2.5 Turbo II and matching auto...! ;-)

If it's behind a V6 engine, it'll fit fine. Grab everything -- shift
cable, kickdown cable and bracket, speed/distance sensor, gear shift
indicator plate inside the van, and engine control computer -- go through
the trans, and swap it in.

If the '89 is a 4-cylinder, the trans won't fit.

It is a tremendously good idea.

DS

 

Dan, when I replied I thought he might have a 2.2L in his van. After I posted
he stated that he had the 3.0 V-6, so I have to retract comments that do not
apply.

My mechanic makes his living repairing cars and teaching others how to do the
same thing. He has a line up of fellows who come to him with problems that
others cannot solve.

Like I said, I assumed a 2.2L engine in the OP's van. My mechanic never
inferred anything about "The 3-speed auto will fit in place of the 4-speed if
you install a different shift cable and put in a kickdown cable and..." as
that is your inference.

To end any head-bashing, I admit that I made a mistake assuming the van had a
2.2L engine. That assumption made an ass of my comment - ANY ONLY of my
comment..

There! Everyone feel better? Lets try to help the OP's concern and stick to
that without passing judgment on anyone else's abilities

 

DS:

I have a three-speed that came from another Caravan. I assume it's the
A607. Not sure if it has all the accessories, though... Would it be
difficult to find them in a junkyard?

Any axles or other "big" parts that need to be swapped?

Thanks,

--kirk

re:

 

A670, if it came from behind a 3.0 V6. (If it came in a 4-cylinder, it
won't fit with your V6).

Probably not, no.

Nope.

Mount brackets *may* differ, but I don't think so.

DS

 

Thanks, DS,

I'll check with my tranny guy about switching to the A670. A little
birdie told me I'd be a lot happier with it!

BTW, some guys have swapped in 5-speed manual trannies into their
Caravans -- saw it on the 'net. Driving hassles aside, any thoughts on
what the relative longevity of a 5-speed manual Caravan might be?

Thanks,

--Kirk in Minnesota

re:

 

There is a 5spd that mates to the 3.0. It was used in AP-bodies
(Shadow/Sundance) and while I am not certain on this, it *may* have been
used in AJ-bodies (LeBaron coupe/convertible). I have no idea whether it's
robust enough to haul around a minivan. There are *very* strong 5-speeds
available for the 4-cylinder engines.

DS