This is my issue and yes I do know before anyone say the 261 is for heavier duty. I just want to know if there will be issues my husband uses the truck for a daily driver and the 4 wheel drive may get used twice a year during hunting season if we have snow during that time. My main concern is so he doesn't keep driving it and the whole drive shaft locks up. So I have a 246 and I want to put it in my 2002 GMC 2500HD sierra that has a 261. I can not find a compatibility chart anywhere and when I went to the local junk yard there book didnt even have my I'd tag listed for my truck and I know it's original part. Here pics of tags.

 

Do you have push buttons or a floor shifter? Also, why the swap?

 

mine is a floor shifter. Reason for the swap is the 261 transfercase is bad. Before dishing out 1500 for a 261 I have this 246 given to me and try to find out if anyone knows if the are compatible or not.

 

You can't use the 246 without considerable investment of both money and time. It is an electrically shifted case, and you will need the transfer case control module, BCM programming and associated buttons to control it. The wiring may or may not already exist in your truck. Aside from the cost due to electronics, it is not a very desirable case; they are considered pretty weak, and prone to a lot of correctable but still annoying problems like pump rub, clutch wear and accelerated chain/bearing wear.

The final reason you cant use it is the input is 27 spline, not the 32 spline you need. You can mix and match inputs from other cases, or for ~$300 you can buy a swap input gear

I would get rid of that 246 and get a 32 spline 241 at minimum. They can be sourced from 88-98 GMT400s, both 1/2 and 3/4t trucks w/ 4L80Es or manual transmissions. Or pony up and get a 261 for your truck and have a direct swap

 

That's what I needed to know. I suspected that but had another person telling me it would work. Me being a female figured I best go and get a second opinion glad I did. Knew I should of stuck with my gut. Thanks again.