Does anyone know if a 3-speed w/OD trans from a '95 Sidekick 4-door 4x4 would fit in my '90 Tracker 2-door 4x4?

Would my ECU be able to handle the OD?

Is a Suzuki 3-speed with OD essentially a 4-speed or is this some kind of electronic OD?

Thanks for any help.

There is no "three speed with overdrive" tranny. The three speed has a lockup torque convertor. The four speed has the overdrive gear. A three speed is completely hydro-mechanical except for the lock-up solenoid circuit. The four speed is the one that has a separate computer for shifting.The ECU's are different, I'm sure. It may not work. You will need to positively ID what it is you are looking at. Most likely it's a four speed on a four door.

Is the 4 speed a  4L30-E trans
I was told by a trans guy that the  4L30-E
had an overdrive in the front of the trans

Or is the 4 speed in a 4 door not a GM trans

 The three speed is a Turbo 180, the four speed is a Toyota, not sure what the model is. You would have to change the wiring and computer in order to make it work.

Is the 4 speed a  4L30-E trans
I was told by a trans guy that the  4L30-E
had an overdrive in the front of the trans

the 4L30E does not come in a tracker/sidekick, it is basically the 3-speed (3L30) with an overdrive bolted on between the bellhousing and the transmission. I am not sure what the tracker/sidekick 4-speed model is

Thanks for the info guys.

There was an eBay auction that listed the 3spd+OD trans from a '95 4-door and that caught my eye.

I know I've read there was a 4 speed available in the four door models (not sure of the trans #), but I thought I read it was too long for the 2 door.

It sold cheap ($75) and I was thinking it might be worth a try, but the electrical/computer issues on top of the mechanical issues kept me away from it.

My trans was having trouble shifting out of 1st gear a while back.  It all started after a simple filter change  But, after a pseudo flush (drain a couple of quarts, refill, repeat, repeat, ...), it's shifting fine again.  I guess I was just thinking it'd be nice to have a spare on hand for the future in case the problem ever comes back.

Anyway, Thanks again.