Does the speedo affect the trans?

[internetautomart]

my speedo is wonky (I haven't replaced it yet) so it tends to jump all over the place when driving especially when cold
well today it was cold this morning and the car didn't want to shift into OD.
I was stuck running in 3rd gear, which I know isn't good for my MPG.
I'm thinking that the VSS in the cluster relays the info to the TCU and the TCU figures out what gear is "best" based on that along with other (TPS) inputs.
am I remotely right or does no one know and I'll find out once I replace my cluster.
I'd be really annoyed if the trans just took a dump on me, as I'll have to get rid of the car.

[BB]

is it below freezing when you have this problem?

If so lube the cable thoroughly and re-insert into the drive. Sometimes they build up moisture and start jumping around when it freezes.

Or just buy a new cable and housing.

BB

[internetautomart]

the jumping is minimally the concern in my mind.
though I will lube the cable when I finally do the cluster.
it's a real pain driving with a very late engaging OD if it engages at all.

[Murphy]

yes it does affect he shifting, the rpm gauge in my car used to not work all the time, it wouldnt shift above 2nd unless you used the manual selector, i could tap on the cluster panel, the rpms would start working and it would shift, i cant remember if my speedo worked or not, its been a few years
i got another cluster panel from a junkyard, it has worked fine ever since, though now i have no clue how many miles on my car, i suspect +300k

[Legacy777]

The trans is designed not to shift into OD when it's cold. This is to help the trans reach normal temp faster.

However, yes your transmission will act weird with a broken/malfunctioning speedo.