'95 Blazer 4wd automatic, 155,000 miles.
Engine runs good
At speeds of 45 to about 60 mph at a steady speed or slight acceleration the torque converter locks and unlocks, can feel it and see rpm change as it does it. Not shifting between gears. Sometimes does it a lot and sometimes not so much. If cruise control is engaged, it doesn't do it. Does it more when the A/C is on than when its off. No codes displayed or stored (cleared them a few months ago when dealing with a bad O2 sensor).
Fluid looks and smells OK. Changed the throttle position sensor, used a new one and no change. Does it in both 3rd and 4th gear, not sure about 1st and second though.

Will a transmission from a '99 fit without changes fit? Have a '99 Blazer, 4 door 4wd automatic with a known good transmission (bad engine) I can pillage.

 

I'm you checked it, but my 95 does that when it's low on fluid

 

I can't say for sure if the transmission is affected, but 95 and 99 use two totally different computer control systems. Since the transmission is computer-controlled, I'm guessing it won't work.

 

Tom, was afraid of that.

On the other hand, it's fixed. A new TPS and 1 quart of fluid fixed it right up. Works like irs supposed to. Now to find where that oil went.

 

Check fluid level in your transfer case. Front seal in t-case goes bad and allows transmission fluid to run in and over fill the case. Be ready when checking level as it will get real messy real quick!
good luck.
Brad