I have a 1992 SE that I need to repleace the Tranny on. Question is I need a 4T60E transmission and I have found one in a 1999 Bonneville and a 1991 Grand Prix 3.4L that has the 4T60E. Will they swap over directly or will changes have to be made in order to complete this correctly? The 1999 Bonneville is local and pretty cheap at only 125.00 with low mileage. I would really like this one if it will go. The other is more and I would have to pay shipping.

The 99 is a 4t-65 E. Not the same, and some consider it not so reliable. Your best bet would be to get the 91 GP tranny. But for 125 get that 99 tranny, and sell it and make some money!

What other vehicles can I look for to swap the tranny from and what years?

Pretty much all GM FWD V6 automatic cars thru 96 have the 4t-60E. supercharged cars have a beefier version. Not sure 100% if the HD is compatable.

However you'll need to use your halfshafts etc since not all FWD have the same ones.

How much is it worth? It has 50k miles on it.

are there certain years that we know of that are for sure the same?

When I was doing my investigating for a new transmission for my 93, I was told that the 92 and 93 transmissions are interchangable...and that'* it for those years! 94 began the year of a different pin-out.