I have a 700r4 that will not lock the converter untill the trans gets above 100 degrees.After that lt works great. Is there a temp switch in the trans?

 

That function is usually in the ECM. Some 700r4's have a temperature switch in the pan. This usually forces the TCC to lock once the trans starts to overheat.

RBob.

 

No temperature switch in a stock F body 700R4.

 

Never seen a temp switch in the tranny, might be in some though, but normally the ECM will trigger the converter when the engine gets to about 150 degrees. Probably some variation on different year cars with that.

 

That is a broad statement to make. There are 3rd gen f-body's with 700r4's that have a temperature switch. Which locks the converter during overheat conditions.

RBob.

 

I've never seen a wiring diagram for a stock thirdgen 700R4 that included one. No listing for any temperature switches in the P&I.M., either.

Other cars, yes. My 4L60 from a 93 Caprice has one.

 

1992 Camaro FSH, section Automatic Transmission Diagnosis, page 4L60-43, bottom diagram, type 18, model FB.

That is the stock transmission in my '92. Having installed a Trans-go kit along with replacing the TCC soleniod and associated wiring harness, I can atest that there is a temperature switch.

RBob.

 

Interesting... I found it in the PIM, but not where I would have expected. 4.054 group, P/N 8673634, starting in 1990 for 3.1L and 5.0L, and in 1991 for all 700R4s.

Ok, then, nevermind anything I said about temperature switches.

 

Mod wars!

I love it!



Seriously though, what's the purpose of having the tranny get to a certain emp before it will lock up (or not).

 

The temperature switch will force a lock-up if the transmission fluid temperature gets too hot, in case the ECM doesn't for some reason.

The ECM will prevent a lock-up until the engine coolant temperature reaches a minimum temperature.