91 sentra AT shift issues

<<1991 Nissan Sentra, 1.6L, 3spd automatic, 147,000miles>>
About 3 miles from my house I took off from a stop sign. After the car shifted to third it revved high for a split second then back to normal then did it again but never re-engaged, like it was in neutral. I jiggled the shifter thinking maybe the linkage was the cause, no luck. I shifted down to 2nd, no luck, the engine still revved as though in neutral. I shifted to 1st, and I had 1st. I got to my destination just a mile up the road. When I tried leaving it wouldn't shift out of 1st unless I let off the gas, then it basically shifted to "neutral", when I'd get back on the gas it would rev momentarily then go back to first. I have reverse and 1st. I tried to locate a dipstick for the trans. fluid but couldn't find it? Any help is greatly appreciated.

i dont know for sure about that transmission, but if theres no dipstick, then theres a fill plug, and the fluid is probably checked the same way as a diff/manual transmission. if theres no fill plug, the speedo cable is the fill hole. and should have some sort of fill line on it. if the transmission is full and the fluid is good, you might be needing a new tranny soon.

Sounds as though the forward or low clutches are burnt - there is no dipstick - only fill and drain plug check the fluid that way - it obviously shouldn't be black or have a burnt odor to it.

I found the dipstick. It's on the drivers side under other stuff, it's just a sphere shaped thing, no loop like the engine oil dipstick and it's black. Another source also mentioned the forward clutch and I told him the fluid was a gray color, not real dark and doesn't really smell too burnt but obviously it's not supposed to be gray. I'm getting ready to pull the trans. and swap it with one from a junkyard. Junkyard wants $250 and is offering a 30day warranty. Hopefully the swap is relatively easy and the "new" trans. lasts a while. Thanks for all your help.