When I had the trans pan off my RE46, I installed a trans drain. For the last few months its been marking its spot in the garage because the drain plug is leaking. Its something I would address when I drain the fluid the next time, it really isn't anything serious, but it was the cause of my screw up.

I need to know how bad I messed up.

The trans has 9 quarts of AFT+4 in it. I checked it the other day, and it was just about down to the add line, so I grabbed what I thought was a quart of AFT+4, and added about 2- 3 ounces of fluid to the trans. It turned out, what I added was not the ATF+4, but was synthetic 5W 20 motor oil in a similar color bottle. That motor oil bottle was full, and there is only 2 to 3 ounces out of it.

Can/will those 2-3 ounces of synthetic motor mixed with 8 1/2 quarts of ATF+ 4 going to harm this trans? If there is concern, I'll dump the fluid, change the filter, and add fresh ATF+4, but if the consensus is it won't cause any problem, I would rather wait until next spring to dump the $100+ worth of ATF when its closer to the ATF's normal change time frame.

What do you guys think?

my opinion ? i don't think it will hurt a thing.
i base this on my experience with a 727 [yes, i know it's NOT like the 46RE transmission] i purposely dumped a quart of motor oil into, as per a magazine article i read at the time, stating this would help with lubrication.
that transmission worked for many thousands of miles afterward, with no problems whatsoever.
just my opinion. mileage from others will inevitably vary.

Not to worry.

There's probably more like 10-12 quarts of fluid in that trans,you get out less than 1/2 with a pan drop.

Thanks guys. I'm going to add this to the "don't ever do again" list though.

"ounce of prevention is equal to a pound of cure" I'm sure you have heard it before. Always pay attention to what you put where.

That is for sure. But as this older age creeps in, sometimes paying attention is the short come in judgment.

When we were young pups, it was because it was lack of good judgment that we did less then intelligent things, now that we are older it is because poorer eyesight and assumption have taken over any form of judgment. "It looks like the right bottle, so it must be the right stuff. I'll read the label if it doesn't look quite right." It didn't look quite right, fortunately, the small funnel only held a couple ounces and was slow entering the dipstick tube.