A/T - 700R4 Case Switches Installed On Outside Of Case

TSB 86-48 (Sept)

SUBJECT: 700 R4




Some THM 700R4 transmissions have switches installed into the outside of the case, in either the 3rd clutch pressure tap, or the 4th clutch pressure tap, depending upon the switch used.

Figure A:

Is a 3rd clutch switch that is used with the L-4 engine. The function of the switch is to release the air conditioner compressor during full throttle downshifts. Switch is normally open (N.O.) and closes at 42 psi (GM Part # 14036254)

Figure B:

Is a 4th clutch for gas 4 wheel drive trucks. Switch is normally closed (N.C.) and opens at 42 psi. Its function is to bleed E.G.R. in 4th gear on 1984 California gas 4 wheel drive trucks.

Figure C:

Is a 4th clutch switch for diesel 4 wheel drive trucks. It is normally open (N.O.), and closes at 26 psi, to bleed E.G.R. in 4th gear on 1984 California 4 wheel drive diesel trucks.