Explorer 4R70W to Dana 20, which adapter to use?

[Fur_Pig]

Hey guys,

I got a complete 99 explorer, 5.0, 4r70 with the AWD "tcase" as a donor vehicle to swap into my bronco build. I am doing a t-shift dana 20 and am a little confused on which adapter to go with. I've read threads that say go with the ZF adapter, cut some off the trans output shaft and mate it up but these also seem to require adding a seal to keep the trans fluid from migrating through the adapter. I also see AA sells an adapter for this, wild horses sells one etc. but I have read other threads that say some adapters require complete trans teardown to install.
Trying to do this as efficiently as possible and would welcome any input I can get from folks who have done this before.

 

[rcmbronc]

I used a ZF adapter to the Dana 20. I think the Advance kit is for a 2 wheel drive tranny. No need to take the 4 wheel drive trans apart.

 

[Bronco-Brian]

Advance Adapters has the right 4R70W kit already. I've used it. Yes you will need to cut about 3/4" off the transmission output shaft - not a big deal. This can be done without disassembly and using a cut off wheel. The stock trans crossmember will also require a modification. The kit worked well for me.

Here's a link to their part number. 4R70W to Dana 20

 

[Timmy390]

From the AA ZF kit instructions
NOTE: This adapter will only work with the "T" style shifter. If your vehicle has a "J" style, it will need to be replaced This kit can be used on a AOD, AODE. 4R70W & C6 4WD transmission. You will need to purchase a seal for the retainer P/N 716764.

Give them a call. Very helpful

Tim

 

[Fur_Pig]

Advance Adapters has the right 4R70W kit already. I've used it. Yes you will need to cut about 3/4" off the transmission output shaft - not a big deal. This can be done without disassembly and using a cut off wheel. The stock trans crossmember will also require a modification. The kit worked well for me.

Here's a link to their part number. 4R70W to Dana 20

What I found out talking to AA for clarification is that the 50-2704E kit requires you to take apart the trans tail housing to swap their output shaft.
He recommended I go with the 50-2704A and deal with the fluid transfer issue by sealing the vent in the adapter housing. He said the fluid wouldn't make its way through the sealed bearing and into the t-case.

 

[Bronco-Brian]

I looked at my paperwork, I have the 2704-A kit. Glad you got clarification. I love the trans-bought a us shift to control it.

 

[904Bronco]

50-2704E kit is used in two wheel drive 4R70W, and can be used in the 4wd tranny if you need disassemble it. It is 1.5" longer than the C4 Tranny/T-case assembly.

50-2704A kit is for the 4wd tranny, it uses a clocking rig with a spud shaft and as noted you need to trim back the 4wd output shaft. Overall, this makes the Tranny/T-case about 3" longer.

If for any reason that you need to go into the 4wd tranny, A/A recommendation to me was go with the E kit if I could, which I did as the tranny was a core.

I went through exactly what you are doing on my last build... Good luck.

 

[scotte6]

Can anyone elaborate on what is required to disassemble the 4R70W? Special tools? I bought the kit (50-2704E) from WH and they told me I could cut the shaft off my transmission without going into it. From what I am reading here, that is not true.
I have a transmission from a '99 mountaineer.
I have a "J" style transfer case from my existing build, but can pull a "T" style from a donor I have.

 

[Jalikek]

Can anyone elaborate on what is required to disassemble the 4R70W? Special tools? I bought the kit (50-2704E) from WH and they told me I could cut the shaft off my transmission without going into it. From what I am reading here, that is not true.
I have a transmission from a '99 mountaineer.
I have a "J" style transfer case from my existing build, but can pull a "T" style from a donor I have.

I was able to build a bracket and slightly extend my ‘J’ style shifter to make it work.
The ZF adapter will put the shifter 3”-4” back, so you will need a new hole in the floor. You will also need to shorten the rear driveshaft and get a new driveshaft for the front.

 

[Broncobowsher]

Changing the output shaft is a lot of work. There are a few special tools needed to get it apart and back together again. Really need a transmission book since things like torque specs on the valve body have to be right. To clarify how much you have to take apart, the output shaft is changed through the front of the transmission. Which means everything in front of the output shaft (all the gears and clutches) all have to come out the front and go back in through the front of the transmission. When (re)building a 4R70W the first part you install is the rear output shaft.

The E-kit has a unique output shaft. No cutting or trimming of a stock shaft will work. You have to use the shaft for the kit.
The A-kit (4WD transmission) is a no-rebuild kit. Just bolt on. Only works with the factory 4WD output shaft and tailhousing.