70R4 internal wiring revisited...

[denson1932]

Lots of U-Tube help out there but here's what i have ...need to ready it for our "62 Impala SS 'Raggedy Ann'.
It is out of a 1992 Caprice...the stamping appears to be 2BHM308A...it has no external pressure ports...inside it has a single terminal internal pressure switch..it has a 2-wire solenoid...it also has a dual terminal switch i think a temperature switch?...both switches are NO (normally OPEN)...at least they both measure OPEN when i took the pan off and measured them.
I have already gathered up the parts for mechanical speedo...I have 17T red drive gear and ordered 42T green driven gear for use with 3.55 rear gears and 235/75/R15 tires.
I need to hook 12V to the top of the solenoid and to the top of a external relay coil i will add...i think the internal pressure switch signal can be usesd to drive the bottom of relay coil to ground then the relay contacts will ground the bottom of the solenoid but only when the temperature rises switch allows it?

 

[Jim Sullivan]

I picked up a brake light switch that also had a switch for cruise control. I ran my feed for the lock-up through a dash switch to the cruise control part of the switch, which cuts power to the lock up when the brakes are applied(or I switch power off). I can't remember now if the wire then runs through a vacuum switch to the solenoid or if the vacuum switch is on a separate circuit to the solenoid. I'm not sure if this was in the TCI instructions or I found the info on line. Don't know if this is what you were inquiring about.

 

[Don Jacks]

Those switches close when pressure is supplied at certian points.At light throttle the trans goes into 3rd at about 33,3rd.plus convertor at about 37m,4th.at about 42,4th converter clutch at about 47 when everything is wired correctly.

 

[denson1932]

OK good idea the vacci switch and the brake interrupt switch.
Any donor vehicles out there for a vacci switch?

 

[Don Jacks]

80-87 Chevy pick ups and vans,82-86 S-10's 7980 Cameros,Corvettes,and any other full and mid size cars had what you need.In fact the wiring harness is stand alone and easily removed for easy reuse.81 later cars went by ECM,Trucks in 87 or so except for California.One thing on the factory stuff.The ported vacuum line for the switch is routed thru a vacuum switch on the thermostat housing to make certian that the clutch can't come on until the coolant temp reaches at least 140 degrees.This TVS is an option for you,you can use it or not just run the line from the ported side of the carb to the vac.switch.Many times Chev used a vacuum delay valve just before the switch.This too is optional.

 

[ragtp66]

Lots of U-Tube help out there but here's what i have ...need to ready it for our "62 Impala SS 'Raggedy Ann'.
It is out of a 1992 Caprice...the stamping appears to be 2BHM308A...it has no external pressure ports...inside it has a single terminal internal pressure switch..it has a 2-wire solenoid...it also has a dual terminal switch i think a temperature switch?...both switches are NO (normally OPEN)...at least they both measure OPEN when i took the pan off and measured them.
I have already gathered up the parts for mechanical speedo...I have 17T red drive gear and ordered 42T green driven gear for use with 3.55 rear gears and 235/75/R15 tires.
I need to hook 12V to the top of the solenoid and to the top of a external relay coil i will add...i think the internal pressure switch signal can be usesd to drive the bottom of relay coil to ground then the relay contacts will ground the bottom of the solenoid but only when the temperature rises switch allows it?

For the wiring follow this video it is super simple. You do not need to remove the accumulator just use small channel locks to remove the pressure switch.

from summit racing:
trans cooler lines pre bent ssh-oclf01
pigtail connector SUM-890150
ADO-8643710
2 of PCO-5665PT
ADO-D850A

Your brake light wires will connect to the spade terminals closest to brake pedal. Second set of terminals 1 wire to key hot in run to fuse box other terminal wire to the pigtail at the trans case. (sum-8901500).

That is all. May need conversion u joint to adapt 700r4 to the x frame driveshaft. Neapco 3-3130 or Spicer 5-3022X or Precision 372

 

[Don Jacks]

I'm not a fan of this set up.The factory used both 3rd.and 4th.

 

[ragtp66]

I'm not a fan of this set up.The factory used both 3rd.and 4th.

Factory also used a crude pcm/ecm to control it. Not sure why having a lockup in third gear would be useful I am all ears if you care to explain why. I rarely drove in 3rd gear unless I was towing something. I have wired up a good 7-8 of these the same way and never had an issue.