4runner Transmission Issue

I have a 2001 4runner. It lost Reverse so I bought a donor 1999 4runner. I matched the A340f transmission and dropped off at my Mechanic to do the swap.
He had personal issues and it sat for almost 6 months. The Mechanic that pulled the donor Trans was not the same person to install in the 2001 4runner. Everything bolted up, when they went to hook up the wiring the plugs are different. The Mechanic tells me the trans that came out is an A340f 3d830 and the one I bought as replacement is an A340f 3g100. Can anyone help me out? His solution is to scrap the truck or get a rebuilt Trans for over $3k. This 4runner was bought for my daughter to drive and the body has no rust. I have everything from the donor 4runner except the wiring harness that was cut when they pulled the trans.
Thanks for any help!

 

Did they say what plugs? If you were to swap the neutral safety switch there should not be any issues. But even the current one should work if I remember. Only difference I can think of is the t cases.

 

Where ya located? I’ve got a trans out of an 01. Should bolt up pretty damn right. Yours, you just have to pull it

 

Im close to Allentown PA. They told me "the wiring" was different? I Have been looking for a solution online I know there has to be a way to make this work?

 

They just told me "the wiring" was different?

 

Pic from rock auto. Looks like there is a difference in the plugs . Change was upto 7/2000 then the radiused corner plug 8/2000 on.