Do not drive the car. Have it taken to a transmission specialist who will drain, flush, and replace the fluid. Most motor oil is too thick, and not compatible with the operation of the transmission. It could cause severe damage within a very short time.
seven
Syncromesh Transmission Fluid, you can only get it at the dealerships and it's about $15.00 a quart.
How many quart of transmission fluid is requier for a Chevy impala 2007
1 quart
Need to remove a quart of trans. fluid to add a quart of lucas trans conditioner. Does not have a drain plug.
One quart.
About 1 quart
3.8-4 quarts of motor oil. 2 quarts of transmission oil 1/2 quart if changing fluid in shifter turret 1 quart of differential oil
Do you mean into the engine? If so it depends on how little; a quart is too much for a small engine. There wouldn't be any immediate damage but change the oil before running the car again.
It uses a special kind of transmission fluid that you can only get from the dealer. Cost about $14 per quart, but it is what you must use.
Your 1976 sportster holds one quart of fluid. I use HD Sportlube or HD PRI ANDTRANS LUBE, but in the olden days I used a 20 wt non detergent motor oil. This fluid lubes the clutches and transmission gears and primary chain.
You failed to mention what fluid you accidentally put in. In any case, have the transmission fluid flushed out and replaced with the proper ATF right away.