hey guys, thought i would give you an update to my post awhile back
700r4-no-overdrive-reverse

i picked up a used 700r4 off craigslist. an put it in over new years.
i wanted to get a later model with the aux valvebody.this one is an 1988 model.
the trans shifts good but there is some lugging, like its in to high of a gear for the lite throttle speed im going .
i wanted to test the tcc lockup circuit an make sure its working properly.
so i installed a test light on the F terminal of the ALDL plug an the purple wire on the brake switch. an went for a ride.
it appeared to me that the light came on when i hit 2nd gear an stayed on thru 3rd an 4th gear an the lite goes out when i press the brakes .
in (D) felt four shifts but when did the lock up occur when the lite came on?
anyway that left me with more questions than answers
i guess from reading all the info out there about adding lockup circuits to hot rods
i thought tcc lockup only happens in 4th an could be added to 3rd for towing.
there doesn't seem to be alot of info out there on factory lockup control.

i did find this in post on the s10 forum.
The ECM will engage the TCC by grounding circuit 422 to energize the TCC solenoid.

The TCC will engage when:
the vehicle speed is over 30MPH
Coolant temp is above 149 degrees
TPS output steady
Brake switch closed

an another post
od doesnt kick in when your in 3rd,, your feeling the tcc lock up in the converter, it will feel like another shift

here is how the 4l60e makes its shifts:

1-2 shift

2-3 shift

then the tcc locks up(feels like another shift)

3-4 shift ( lock up may or may not stay on right away depending on tps/load

another common miss understanding
on the 700r4/4l60 overdrive means 4th gear.
not tcc lockup . correct?

-Yes OD is 4th

could you guys shed some light on this
im thinking about adding a toggle sw to the circuit to disable it .driving around town.

-A toggle switch is a good idea if the TCC is locking to early or under light throttle and causing the engine to lug. An adjustable vacuum switch can be use in the circuit to limit this problem also.

For reliability the TCC can not remain locked under heavy load. The TCC is not designed to handle a high load.

-Precision Industries makes a Vigilante lockup TC with a 5 disc clutch that can be locked at full throttle reliably.

Also note that the GM 700R4 (4L60) transmission does not route fluid to the cooler unless the TCC is locked.
is this correct?

-Fluid does go thru the cooler when the TCC is not locked, when locked additional fluid is sent thru the cooler.

-In some 700R4's and 2004R's the ECM can lock the TCC in 2nd, 3rd & 4th.
The Corvette, Z28 & TransAm stock 700R4's would hold 4th gear under WOT conditions without downshifting to 3rd.

Maybe I didn't miss anything. :thumbup:

 

no there wasnt anything worth missing
just a greasy mess!
glad to get my little truck going
now i need to find a 3.4l for it.

i guess this is how its controlled thru the ecm

The TCC will engage when:
the vehicle speed is over 30MPH
Coolant temp is above 149 degrees
TPS output steady
Brake switch closed

Fluid does go thru the cooler when the TCC is not locked, when locked additional fluid is sent thru the cooler.

i was wondering about this ,info was from an artical i found on net.

thanks for the help SSedan64 ill try putting a toggle sw on the circuit.

 

The toggle switch is easier. Superior/Fairbanks sells the Adjustable vacuum switches that go in the TCC power circuit to help stop lockup cycling & premature lockup. K052= 1-6 inches, K058= 6-22 inches of vacuum. The stock GM switches aren't adjustable. Of couse these are for Non-E, 700R4/4L60 trans.