'98 Wrangler, no reverse when cold

Please help me understand this. Five or seven years ago I
I bought a high mileage Wrangler with a standard 3-speed
automatic transmission. After two changes of filter and
transmission fluid and minor tigntening of the front band
over these past years I assert that all is now well in the
forward direction.

Reverse, however, remains a problem...but only when cold.
No problem at all after a five minute drive. On a cold start
I might be able to gun the engine and have it lurch into
reverse. Also, if I let it idle in Neutral for a few minutes
it might then be able to hard-shift into reverse with a mild
clunk. Seemingly this warm-up behavior only occurs from
Neutral, not from Park, but that's just a hunch.

I can live with this reverse situation, but I'm just
curious about what the actual failure mode might be.
Does anyone have any ideas? Any pointers to online
"how it works" documentation?

--
If it feels safe, you aren't going fast enough." - Parnelli Jones

Jack Myers wrote:

> Please help me understand this. Five or seven years ago I
> I bought a high mileage Wrangler with a standard 3-speed
> automatic transmission. After two changes of filter and
> transmission fluid and minor tigntening of the front band
> over these past years I assert that all is now well in the
> forward direction.
>
> Reverse, however, remains a problem...but only when cold.
> No problem at all after a five minute drive. On a cold start
> I might be able to gun the engine and have it lurch into
> reverse. Also, if I let it idle in Neutral for a few minutes
> it might then be able to hard-shift into reverse with a mild
> clunk. Seemingly this warm-up behavior only occurs from
> Neutral, not from Park, but that's just a hunch.
>
> I can live with this reverse situation, but I'm just
> curious about what the actual failure mode might be.
> Does anyone have any ideas? Any pointers to online
> "how it works" documentation?
>

Since I usually have at least one clunker around, I see this fairly often.
Usually, it's a gummed up control valve and goes away with fresh fluid -
some times just by topping off a low level. Major PITA but nothing fatal -
unless you get on the gas really hard and slam it in.

Sometimes, just cycling through the gears (all of them) is all it takes, but
it will get worse and worse until I change the fluid.

--
Will Honea

"Jack Myers" > wrote in message
...
> Please help me understand this. Five or seven years ago I
> I bought a high mileage Wrangler with a standard 3-speed
> automatic transmission. After two changes of filter and
> transmission fluid and minor tigntening of the front band
> over these past years I assert that all is now well in the
> forward direction.
>
> Reverse, however, remains a problem...but only when cold.
> No problem at all after a five minute drive. On a cold start
> I might be able to gun the engine and have it lurch into
> reverse. Also, if I let it idle in Neutral for a few minutes
> it might then be able to hard-shift into reverse with a mild
> clunk. Seemingly this warm-up behavior only occurs from
> Neutral, not from Park, but that's just a hunch.
>
> I can live with this reverse situation, but I'm just
> curious about what the actual failure mode might be.
> Does anyone have any ideas? Any pointers to online
> "how it works" documentation?
>
> --
> If it feels safe, you aren't going fast enough." - Parnelli Jones

On the old 3-speed Mopar Torq-Flite designs (aka AMC Torq-Command) the
low-reverse band (inside oil pan toward the driver's side rear) would cause
a no/harse-reverse condition if the band became too loose. Low /incorrect
fluid can also.

The quickie test, if you have a tachometer in your instrument cluster, is to
drive to a safe place with room to stop in and NO traffic of any kind and
shift to 1st.

Then with the brake held firmly, accelerate the engine until 1/4 to 1/3
throttle is reached.

With the factory torque converter and tight bands you should not go over
1600-2400 rpm.

If the engine continues to increase rpm beyond 2400 then something is
slipping in the low-reverse system.


--
Budd

I am not your everyday SuperHero
nor do I play one on TV.





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