[AT] OT - Pickup Transmission Question

[Rob Gray]

I have a '90 F150 automatic 4X4 which started to have shifting problems 
the same day as the speedometer started to "bounce" around from zero to 
the actual driving speed. The transmission continued to shift worse and 
worse as the speedometer got worse and worse until the speedometer 
stopped working at all and I could barely drive the thing due to 
extremely off-timing gear shifting. This was supposedly one of the first 
years for Ford's electronic transmissions so I'm guessing that these 
trucks use the  speedometer to assist the auto tranny in "knowing" when 
to shift?

I left it at AAMCO and they said that they have to open up the transfer 
case and take a look. Has anyone experienced this sort of problem before 
that could give me any insights as to how big a job it was to get 
fixed....? I just had the torgue converter on the transmission replaced 
6 months ago and with a truck this age I'm somewhat leery of digging a 
hole too deep expense-wise... Maybe I should park it out in the field 
and start one of those old vehicle "collections" you see on some places 
here and there.... ;)