1994 Plymouth Voyager transmission

[gtb]

94 Plymouth Voyager 3.3L

When coasting downhill at 50 MPH or so in overdrive the engine speed
drops below 1000 RPM and then the transmission jerks into 3rd gear.
Shop replaced transmission with a used one but it started doing the
same thing in a few days. Seems like there must be an external cause
such as bad info going into transmission computer. Does this
transmission have any vacuum control at all?

Otherwise it is fairly smooth, accelerates fine, no worn out disc
symptoms. Problem virtually goes away in sub-freezing weather even
driving 40+ miles.

Your thoughts please.

Thanks,

john

When coasting downhill at 50 MPH or so in overdrive the engine speed
drops below 1000 RPM and then the transmission jerks into 3rd gear.
Shop replaced transmission with a used one but it started doing the
same thing in a few days. Seems like there must be an external cause
such as bad info going into transmission computer. Does this
transmission have any vacuum control at all?

Otherwise it is fairly smooth, accelerates fine, no worn out disc
symptoms. Problem virtually goes away in sub-freezing weather even
driving 40+ miles.

Your thoughts please.

Thanks,

john

[Leviathan]

Are you using the Cruise Control when this happens?

"gtb" <goodTweetieBird@...........m> wrote in message
news:2768b1a0-106b-42a5-a1bc-e929a312901d@w35g2000yqm..............com...
> 94 Plymouth Voyager 3.3L
>
> When coasting downhill at 50 MPH or so in overdrive the engine speed
> drops below 1000 RPM and then the transmission jerks into 3rd gear.
> Shop replaced transmission with a used one but it started doing the
> same thing in a few days. Seems like there must be an external cause
> such as bad info going into transmission computer. Does this
> transmission have any vacuum control at all?
>
> Otherwise it is fairly smooth, accelerates fine, no worn out disc
> symptoms. Problem virtually goes away in sub-freezing weather even
> driving 40+ miles.
>
> Your thoughts please.
>
> Thanks,
>
> john

[jh]

On Mar 6, 3:19.pm, "Leviathan" <leviat...@q.com> wrote:
> Are you using the Cruise Control when this happens?
>
>

Sorry, didn't see your post at first. Cruise control was on but not
engaged.

jh

[Leviathan]

O.K. Thought it was downshifting and using the engine as a brake to slow
down.

"jh" <jvh75021@..........> wrote in message
news:0afcfab9-096d-477d-88d6-594608841194@m4g2000vbp..............com...
> On Mar 6, 3:19 pm, "Leviathan" <leviat...@q.com> wrote:
>> Are you using the Cruise Control when this happens?
>>
>>
>
> Sorry, didn't see your post at first. Cruise control was on but not
> engaged.
>
> jh