4R70W - upgrades for towing?

[bronchole]

I figured this would happen. I recently replaced my 5.0 with a 331. Figured the 100K miles plus (previous owner had rebuilt) trans wouldn't survive long. It no longer has 2nd or 3rd after a very mild local off-road trip. I think a bit of the trail cruising I did in 2nd gear finished it off.

I tow a trailer weighing in at about 4500 pounds on the freeway frequently. I also off road this rig. Motor was built and cammed for maximum torque. For those that can't look at my signature to understand what this rig is:
- 35" tires
- 4.88:1 gears
- Freshly built 331 (5.0 stroker) with TFS heads and torque cam
- headers
- All cats present, no muffler, exhaust out the back
- Monsterneer weight ~4500 pounds
- Normal trailer weight ~4500 pounds (2014 Maverick SXS in enclosed 16' aluminum trailer)

I have build a 4R70W before for my 67 Bronco. I am considering building one myself for this. I have a 4R70W from a 1996 Explorer 5.0 on the side of the house that I know was working when I blew up the motor in that rig.

What I am wondering is what mods/upgrades should I consider when shopping for parts or a potential vendor to build a 4R70W for towing?

Thanks,

Dan

 

[Turdle]

Just throwing this out, but a bad tps will prevent upshift to 2 and 3. If it got wet it could be the culprit. Hoping for you.

When mine went all it had was 1st and reverse gears.

 

[bronchole]

I will be checking the TPS and the transmission mounted shifter position switch thingy this weekend. I think a failure of either of those may create what I am having. Thanks for the reply.

Still looking for the upgrade info though. I know a transmission is in my future this year.