I'm so glad this forum is here. I just wanted to share an article I have been working on for some time. I'm sure it has a few errors, and needs some touchups. When I installed a 98 4r70w into my car, there was alot of confusion on several procedures, and when I got it together I just wanted to share what I did to make it work.
Please give me some constructive criticism.
Installing a Late Model 4r70w in a MN12
This article will outline the installation of a 1998 Lincoln Mark 8 4r70w Transmission, in a 1995 Thunderbird LX. There are alot of low mileage late model 4r70w's in salvage yards across the country, and they are a better (and less expensive) alternative to rebuilding your 4r70w.
MLPS from your old transmission for the new transmission. The part number if you buy new is SW-5977.
TCC Solenoid from your old transmission for the new transmission. The part number if you buy new is F2VY-7G136-A.
Mark 8 Flexplate- Part Number F3LY-6375-A.
Transmission Pan Filter Assembly- Part Number FT-105.
MN12 Transmission Mount (it is a good idea to buy a new one instead of reusing your old one, unless the old one is brand new)
Inline Magnetic Transmission Filter (a must if you are replacing a failed transmission, and not replacing the radiator)
Remove transmission per Factory Service Manual.
Transfer MLPS, and TCC Solinoid to new transmission from the old transmission, or install new parts.
You need to trim the connector off the TCC solinoid to make it fit. The new transmission does not have wiress.
Failure to swap the MN12 TCC Solinoid will fail the driver.
Failure to swap the MLPS will cause the transmission not to shift.
Install new Lincoln Mark 8 Flexplate, and use Mark 8 Torque Converter. Do not use the MN12 Flexplate and converter.
Remove Lincoln Transmission Mount, and install MN12 Mount.
The electronic plug on the outside of the transmission has different pin assignments between the two transmissions. The problem is that the Lincoln Plug has one less hole, than the MN12 Plug Does.
There are two ways to solve this, you can re-pin the connector per the diagrams below, and drill a hole for another pin.
Or you can install the MN12 wiring harness in the new Lincoln 4r70w. I chose to do it this way. Just swap the tbird wiring harness into the new transmisssion and be done with it.
Here are the diagrams if you choose to repin the connector.
1998 4r70w Pinout
the pinout is:
Pin Number Circuit Circuit Function
1 — NOT USED
2 359 (GY/R) Signal Return
3 473 (R/LB) Torque Converter Clutch (TCC) Solenoid
4 361 (R) Vehicle Power
5 923 (O/BK) Transmission Fluid Temperature (TFT) Input
6 925 (W/Y) Electronic Pressure Control (EPC) Solenoid
7 237 (O/Y) Shift Solenoid 1
8 315 (P/O) Shift Solenoid 2
9 — NOT USED
10 — NOT USED