88tatpi

I have installed a 700R4 from a 1988 C1500 Chevy truck that had a 305 TBI motor into my 1989 305 TPI Firebird T/A. I do not have the original Firebird transmission. Are the internal electrics; solenoids, swtiches wiring for the TCC different in the trannies from TBI to TPI? The factory truck wiring book does not show a TCC feature. It shows only a "kickdown" solenoid and relay running off the brake light switch.

My guess is I will have to aquire a valve body with electrics made for the TPI motors.

Any insights?

greggbruce

iTrader: (1)

there are about 8 different wiring combinations for that vintage of 700 (4l60)
some ground the solenoid, some power the solenoid, others have temp switches and 3rd and 4th switches, ect.

if you had the code off the original trans, we could get a schematic and make the wires match what it's supposed to.

I would say take it to a good trans guy and have them figure out how it's supposed to be wired and make them do it. you'll be money and time ahead as opposed to fighting with it for months making it right and to keep it from blowing fuses.

don't NOT hook it up, when the tcc is locked up, it reduces the heat the trans creates from slippage in the converter.
if you're on a long trip it might fry it from overheat if the tcc don't work.

88tatpi

As best as I can see on the trans: cast onto the bellhousing: MD8.
cast onto the passenger side center case "27"
stamped onto the right side just above the oil pan right rear area near tailshaft: 1 wmb 8 163 A

My books do not show a "wmb" series trans although I guess that 8 is for 1988 and 163 is 163rd day of the year made and A is the first/morning shift.

Anyone know what the wiring/solenoid set-up should be ?
Thanks

greggbruce

iTrader: (1)

usually, the number before the 2 or 3 letter code is the year, in your case a 1-- which would tell me that it's a 91-- are you sure this is the ORIGINAL trans from the truck??

either way, it still won't be the same as what the 89 f-body is.

if you email me, I will see if I can find it in a service manual for the 89 f-body.

oh yeah, I forgot to say in my last post that the valve bodies are virtually the same, but the electronics are different.

Slowmaro91RS

I kinda hyave a similar problem. In my 91 rs I originally had a 305 TBI. I swapped in a 305 TPI out of an 88 Iroc. My converter locks up in second gear instead of third and it keeps locking and unlocking at cruising speed. It's been driving me nuts for a long time now and nobody seems to know how to fix it. Not even the tranny shop that built my tranny. Good luck.