I've noticed for a while that it took a little longer than normal for R to engage so I thought I had issues. Well yesterday I lost R completely.

I called a local junk yard and they have 2 4R70s and 1 4R100

4R70 w/130K for $650
4R70 w169K for $550
4R100 w/131K for $750

I'd probably go with the 100 if it bolts up.

Is the 100 a direct replacement of the 70? Notice I have the 5.4 4x4
Would this cause tune issues?

Thanks for the help guys.

 

Big time tune issues. You'll also have to change the wiring harness, the driveshafts, trans mount, etc. This is NOT a bolt in, it's a large project.

 

Thanks!

 

If you plan on keeping the truck for a while, I'd consider spending the bucks for a Ford reman with a warranty.