New Build 05 Blazer Mudder
 

Hi I am new here and have a 05 Blazer 2 door 4X4 4.3L engine. I want to make it a street legal mud truck and am looking for advice?
1. Do I do a full blown lift kit on it. the only one i can find that will fit is a 2.5" or do I just cut the fenders to support bigger tires?
2. I am having shifting issues wont go into first sometimes when starting from a stop. have to shift it manually for a bit till it warms up?
3. Can I do a manual swap and if so what all do I need and being a mud truck would it be better to leave it auto?

Welcome. What are you looking to build as far as a mud truck? Are you looking for a daily driver vehicle that can also go off road, or are you looking to build an off road beast that also legal to drive on roads? Those are two very different machines.

1a. If you want bigger tires, you'll almost certainly need something of a lift, even if you're willing to butcher your fenders. I believe Rough Country is the only manufacturer currently making lifts for the S-series trucks. they have a 2.5" lift and a 6" lift. Both have mixed reviews.
1b. If you are building an extreme mudder then you should be exploring the SFA (Solid Front Axle) swap along with moving the rear springs on top of the axle. This will give you a LOT more height and room for bigger tires, as well as stronger axles to handle the abuse.
2. I'm not a transmission guru, but that sounds like an issue with the 1-2 shift solenoid. Hopefully someone with more experience will chime in to help on this one. You could also post a specific question thread in the transmission section of the forum.
3. A manual swap is possible, if this is the way you want to go. I think manual vs auto is a personal preference,and one isn't really better than another. You'll need a donor truck with a manual transmission to get all your parts, including the PCM. You'll also need to get the new PCM flashed by a competent shop to match your VIN.

Good luck with your research and build!