i have a 2005 f-350 4x4 dsl. i want to change the gear ratio and put lockers in. how do i find out what type of axles are in my truck?

 

It's in your owners manual or you can match the bolt pattern here Axle Identification Chart.

You should have a 10.25/10.5" rear and a dana 60 front.

 

so how can i find out what kind of splinds would the axle shafts with out pulling them?

 

You mean the spline count?

I once knew the answer, but I don't think 35 spline is common in OE and Superduties shouldn't have 28 spline axles either. That should leave only 31 spine left. However I am not certain. Unless someone knows for sure, then the only way to check is to pull the axle and count the splines, or you might be able to count them if you pull the cover.