I have a quick question. I am looking into a tranny that I found, but I need to clarify something. The spot I'm looking into was asking if I need a Multicase, 2 wire lock-up plug harness or a 1 wire or a 3 wire?. Can you tell me what he is talking about. They say it is a 1981 oldsmoblie cutlass TH350 tranny.They also have a starfire tranny? I have a 1969 cutlass 350 rocket with jetaway trans

thanks guys

 

Are you trying to change from a Jetaway to TH350? If yes, the shift indicator would need to be changed also.

The plug he is talking about is for a lock-up style torque converter. This would not be used on anything 1980 or earlier. A 69 would not have any torque converter electrical connection. About the multi-case, he is asking if you need a transmission case that fits BOP and Chevy. I would prefer a BOP only case just for originality.

You would probably also need a short tailshaft case. Can anyone answer this?

If they are asking about an electrical plug make sure it isn't a TH250, these are rare and can be identified by the external band adjustment on the upper passenger side of the case. It is a threaded adjustment pin with a locknut. TH350's do not use this but otherwise look similar if not identical.

 

Couple of things. First, you need a BOP case or a multi case. The latter are usually TH350C with lockup converter. The correct TH350 for your car doesn't use a lockup converter and in fact normally doesn't have an electrical connector at all. There is one exception, however. In the early 1970s Olds used an emissions control system called Transmission Controlled Spark. The vacuum advance at the distributor was disabled in all gears except high (third for a TH350). There was a pressure switch inside the trans that closed in third and a single terminal connector on the side of the trans case. If you get one of these, simply ignore the electrical connector if you don't have TCS.

 

Thanks alot guys, so this tranny will work for me cool, now let me see if I can bring him down on the price a little

 

In my powertrain rebuild, the transmission pressure switch on my TH350 was removed and "plugged". The shop indicated that it was leaking through the switch and they said the part is no longer available. From Joe's comment above, I think this is related to the TCS that he references. So a couple of follow-up questions: 1) do I need to be concerned about this or do I need to find a switch? 2) if I don't need to replace the switch, what do I do with the wiring harness to the trans? Thanks for your input.

 

Remove the switch, plug the hole with a 1/8 pipe. As far as the wiring is concerned, I would think if you remove and plug the thermal vacuum switch in the intake you could bypass the TCS system completely. As stated before, all that system does is delay spark advance until the trans is in high gear and the engine is warm. Its a early attempt to control NOX emissions. I don't know all the legal rules for this considering the vehicle age but some state that have vehicle inspections might not like that.

 

Does anyone know if the transmission oil pressure switch is available anywhere? The switch should have 2 contacts positioned at 90 degrees to each other. I don't find an OE part number for it in either the AIM or the Service Manual.

Thanks for any help.

Don

 

You're in SW Chicago..., check with Power Proven in Naperville. I used to do alot of Metric TH250 conversions and diesel to Olds 403 conversions back in the day. Always went to them when in a snag.

Their address is:

POWER PROVEN TRANSMISSIONS
550 W 5TH AVE
Naperville, IL 60563
(630) 983-0635

 

4 days is old??

 

[QUOTE=78Delta;460659]You're in SW Chicago..., check with Power Proven in Naperville.

Thanks for that contact information, I'll get in touch with them.