I am looking into the near future upgrading to the 4.7 low gear kit. I see it comes in 21 spline and 23 spline. Is this 2 different factory options? I know that the 23 will be stronger bit I not full time rock crawling the truck. It's a true 50/50 truck.

the truck is a 85 extra cab, 22re 5 speed.

thx

 

That is the spline count of your input gear. it MUST match with the output of your transmission. %99 chance you have 21 spline in your truck.

23 spline inputs only came factory in gear driven transfer cases behind the r151f in 1986-87 turbo trucks and runners with the 22-ret. It is also used in dual case setups in the rear case because of the extra torque put through the rear input by the front case.

So unless you change your transmission you will not be able to use a 23 spline unless you build a dual transfer case.

go to this webpage and figure out which tranny you have then go from there. http://www.4x4wire.com/toyota/faq/parts/

 

23 spline is not used in all dual case applications. You have to have the 23 splined dual case adapter

 

It's a G58 w/rf1a. Looks good on paper. I am Not wanting to do dual cases it just a med 50/50 truck. Any advice on a 4.7 kit. I am good with rebuilding stuff but I haven't done a transfer case before.

 

Drop zone is correct, I didn't specify enough. Oops. You have a 21 spline input for yours. You will be just fine strength wise and do not need to upgrade to the 23 spline.

If you buy Marlin stuff, you can print of their step by step directions from their website.