In 97-8 there were 3 trannies; the E4OD, 4R70W and the 4R100.

JMC

 

I also just remembered thet the T-case for the Navi and the front diff changed.
97-98 T-case has 2H, A4WD, 4Hi and 4Lo. In 99 the T-case no longer had 2Hi.
The front Diff in 97-8 had vacuum disconnect and in 99 it lost that and remained permenantly connected to be able to use the A4WD. I can see where there would be a few concerns with t-case and transmissions from the wiring differenced between the different model years. For one thing the 98 Shift switch with 2hi doesn't match the t-case from the 99 that doesn't have 2Hi. So when the Gem looks for it it will not find 2Hi and set codes. Little things like that are a small price to pay for the luxury of the navi set up. Now to tie all that to an F-150 you could run into a few glitches. There is no A4WD position on the F-150 switch.......

JMC

 

i found 4r100's on ebay from $1000 rebuilt-$1900 rebuilt stronger. Navi motors from $2200-4000.

Karkraft.com has some nice ones again but pretty pricey. Im going to keep searching online for any salvage yards that might have one.