TH400 ID tag is NOT numbers matching on my car!
#1
TH400 ID tag is NOT numbers matching on my car!
Does this trans. tag mean anything to anyone? I'm pretty sure it's in the location of the original factory tag that SHOULD have the GM ID #, right? I found out from the original owner (my uncle) that this car likely had a rebuilt trans. put in it sometime in the 70's. He thought he recalled having some trouble and they just swapped in a reconditioned one. It's not a big deal, because I won't be showing the car, but I've always thought it was a true "numbers matching" 442! The second picture is the old 455 almost ready to go!
#5
#8
Even without seeing the VIN derivative stamping of the transmission, we can tell it is not the original one for a 1970 442. The tag says it's from a 1967 Buick. (I'm not sure what type of Buick the "BT" code was used on.) Even if this was the proper 1970 Olds TH400, the trailing sequence of digits will have nothing to do with your VIN; they are a serial number for the transmission, that's all.
By the way, it's not uncommon for the tag to lose all of its paint like that, especially if the transmission was rebuilt and put through the parts washer at one time.
By the way, it's not uncommon for the tag to lose all of its paint like that, especially if the transmission was rebuilt and put through the parts washer at one time.
#11
Thanks folks. Yes, the engine # does match the VIN # on the car. My uncles owned this car from 1970 to 1980, then I bought it from them. I've owned it since then, but am just now doing a semi-major rebuild. Interesting that I'm still discovering stuff about it that I didn't know for all these years.
#15
I'm pretty sure it has 2 terminals. This brings up another point. Apparently the "kick down switch" (if that's the correct term) has been unplugged for years, & my mechanic is looking for a correct wiring diagram to get it hooked back up properly. The wires coming out of the trans. end in a double plug in the engine bay with no obvious place to plug it into. Any help on that front?
#16
I'm pretty sure it has 2 terminals. This brings up another point. Apparently the "kick down switch" (if that's the correct term) has been unplugged for years, & my mechanic is looking for a correct wiring diagram to get it hooked back up properly. The wires coming out of the trans. end in a double plug in the engine bay with no obvious place to plug it into. Any help on that front?
Also, find a mechanic who understands the difference between a switch pitch converter circuit and a Transmission Controlled Spark circuit. Your original trans also had a two wire connector, but the second wire was for a COMPLETELY DIFFERENT function. The 1970 cars had an early emissions control system called Transmission Controlled Spark. This used a pressure switch in the trans to prevent spark vacuum advance in any gear but third, to lower NOx emissions. The connector in your wire harness went to a solenoid valve on the intake manifold that controlled vacuum. This is unrelated to kickdown, which is the other (black with pink or orange stripe) wire in the connector to the trans.
The 67 trans used the second terminal in the connector to operate a solenoid valve INSIDE the trans to alter the angle of the stator vanes in the torque converter to change stall speed. A switch on the throttle linkage provided +12V to this second trans terminal.
Again, this is COMPLETELY different in function from how your car is wired. Do NOT connect the TCS wiring to the current 67 trans.
#17
Wow - thanks for that Joe! I'll pass this on to my mechanic. I have a lot of trust that he knows what he's doing, but don't know how well he knows the subtle differences - AND I just determined this is a Buick TH400, so he may not know to watch for that.
#18
All Buick/Olds TH400s from 1965-67 used the two terminal case connector for the switch pitch. All 1970-74(?) or possibly later used the same two terminal connector for the TCS. This is a subtlety that needs to be understood.
#19
So, if I can keep buggin you for information; How do we reconnect it so that I have a functional kick down switch? leave one wire disconnected, and connect the other wire (the black with orange or pink stripe) to...where?
#20
By the way, there are over a dozen 1970 Chassis Service Manuals on ebay right now...
#21
Thanks again Joe - I'll get right on that chassis service manual! Will likely need it again. **edit to say, I just ordered a service manual!
Last edited by safray; May 18th, 2016 at 08:29 AM.
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