Transmission differences
 

I've got a 99 CL3.0 that I bought as a project a few years ago. One thing it needed was a transmission. I held out and waited until I had the money to spare and bought one from a wrecked 98, installed it, and here she sits. I don't have it plated or insured, but I've taken it down the street and it all seems fine. Question I have, there's a sensor on the firewall side of the trans, towards the bellhousing, that the 99 didn't have. It's a rectangular plug with 3 pins in it. What is this? Speedometer works just fine, so I'm not sure what to make of it. I do have a complete 97 parts car that I plan on robbing some things from, and it's got that same sensor on it.

Second question, the 99 has what I'm almost certain to be a vacuum leak. First started the idle goes up to 1800 or so, and finally settles back down to around 1200, but I can hear it. I can't see anything open, and I've sprayed carb cleaner and starting fluid around and nothing makes a difference, so I'm thinking it's under the plenum. Any ideas on what I should expect to find?

Thanks :)

have the same transmission question
 

i have 97 acura cl and i replace the engine and transmission of a 98 acura cl. everything is plug and play but i cant get the speedometer going and the P0700 with a flashing D4 light comes on when i drive it. i'm missimg the same speed sensor in the rear but i think the 98 acura cl has a pulse speed sensor. i dont know what to do. what should i replace. do i have to replacr the whole computet module or wheel speed sensors?

98 cl 3.0