caddy 4t60 viscous converter clutch( VCC ) wiring

[flimbob]

I'm swapping a 3500 LX9 with a 90 model Caddy 4t60 using a 7730 ecm into my 86gt. I was unaware there was a difference between a regular 4t60 and a Caddy 4t60. Seems the Caddy has a VCC( viscous converter clutch ) instead of a TCC( torque converter clutch ). Does anyone have experience dealing with a Caddy transmission and the 7730 ecm? I've tried to search for this information, but can't seem to find any. Any help would surely be appreciated. This basically puts a halt to my swap until I can get it figured out.

[gpse3400]

Well as far as the TCC is concerned, you can hook it up normally, and leave the PWM soleniod un hooked, it will go into lock up but it may be a tad abrupt when it engages.

[robertisaar]

i could have sworn the VCC was on the 4T80 only, not the 4T60s....

besides, a 90 shouldn't have PWM operation anyway, none of the 4T60s did, the 4T60Es started it and that didn't come around until 1991.

[pocket-rocket]

I didn't think the 4t60-e's started PWM until the mid 90s?

[robertisaar]

depended on engine and platform... some of the caddies had it right out of the box in 1991 IIRC.

[pocket-rocket]

Leave it to the Caddies to get the cool tech gadgets... I was thinking normal GM, not the Caddies.

[robertisaar]

looks like C and H cars got it as well in 1991.... so buick, pontiac and olds got them.

it almost seems like everything that wasn't a W got PWM TCC early.

[pocket-rocket]

Maybe that was part of the "we can't give the DOHC 275 hp" deal...

[robertisaar]

i'd like to think of it as part of GM's issue of having a slightly shorter and lighter car with as much refinement as one that costs a few thousand dollars more(H-cars).

also: in 1991, what GM car was making 275HP from the factory? i don't think the L98 vettes did, so that would leave just the ZR1 vettes and likely Syclones, both of which commanded quite a premium over a LQ1 W.

[flimbob]

I wasn't aware of any differences between Caddy and non Caddy 4T60/440T4 transmissions, but you can plainly see from the 90 Deville transmission wiring diagram( attached ) that VCC was used. I searched but did not find any info regarding VCC or for that matter, any 4t60/440t4 transmissions with VCC used along with the 7730 ecm( other than possibly Northstar swaps ). After looking at the wiring diagram it looks strikingly familiar to other 4T60 TCC diagrams ( switches for 3rd and 4th gear and VCC/TCC solenoid ). That got me to thinking maybe it was as simple as swapping out the torque converter and either using a pressure switch or adding a relay to emulate the 125C Fiero transmission.

[robertisaar]

IMO: just wire it exactly like a TCC, it's more or less the same thing anyways.

[pocket-rocket]

i'd like to think of it as part of GM's issue of having a slightly shorter and lighter car with as much refinement as one that costs a few thousand dollars more(H-cars).

also: in 1991, what GM car was making 275HP from the factory? i don't think the L98 vettes did, so that would leave just the ZR1 vettes and likely Syclones, both of which commanded quite a premium over a LQ1 W.

I was refering to the DOHC rumor but forgot to type it, thanks to sleepyness.