using a GEN 3 transmission in an OBS (4x4)

[BOTTLEDZ28]

What issues, if any, will I encounter if I decide to to an LS swap and use the matching trans from the donor truck? I want to drop a 5.3 or 6.0 in my 98 2 door tahoe but it has the floor shifted 4x4 . Will a GEN 3 trans bolt up to the transfer case and work correctly with the floor shifter? Im trying to get away from having to rebuild my current transmission.

[88blazerboy]

What do you mean by matching transmission? Does your truck and the donor truck have the same transmission, or are you wondering if the donor transmission will work with your older truck which - taking a wild guess, probably had/has a 4l60e or 4l80e?

[BOTTLEDZ28]

basically, I need to know what I will have ahead of me if I put a LQ4 in my truck with the matching 4L80e that the LS engine came with from the donor truck? My truck has 4wd with the shifter for it on the floor.

I highly dought my 134K mile 4l60e will last long once I out the 6.0 in the truck so I either go with the 4L80 or buy a rebuilt 4L65e from FLT or RPM.

I just havent really seen and LS swaps into OBS trucks using a 4L80e and the trucks original transfer case.

[88blazerboy]

The 4l60E and 4L80E are different enough in size that depending on where your engine sits (motor mounts) and whether or not you will have to move your transfercase/rear crossmember, your 4wd shift on the floor will likely not match up the way you want it to. I know lots of folks have done this before - especially with 2wd. I'm thinking you are in for a fair amount of expensive fabrication.

I got lucky with my swap because the 700r4 (my old transmission) and the 4l60E were pretty much the same size. The LMG 5.3 that I put in sat exactly where my old engine did, so nothing got moved back - the 4l60E (with the adapter) butted up to my old transfercase, and nothing had to be moved back or shortened. I'm really not too sure about your project. You might want to give Advanced Adapters a call and chat with them. They helped me out a lot, but you still have to take what they say with a grain of salt because they are salesmen before specialists.

[Chevydillan]

Your transfer case will not fit the 4l80 the output shaft is much larger. It should bolt up to the 4l65 with no problems though and you'll be able to retain the factory location and shifter. I don't see a problem with strength of the trans if you
Go with even a mildy built 65e, that 10 bolt will give its life first.

[Pistolpigg]

Try to find a 261 floor shift transfer case for a 4l80e linkage should work with some adjustment

[92 6.0]

You can use your factory transfer with the 4l60/65 like has been said. You can also use it with the 4l80 but you will have to change the input shaft. Not hard to do. But if you go with a 4l80 you will run into issues with drive shaft lengths and the shifter linkage will be just long enough on the transfer to work. You will also have to re-drill the crossmember holes. And this is all assuming you get the motor in the factory location.