Case identification

[Timber677]

I recently purchased an '86 4Runner with a SAS. The truck started its life as a 22RET and someone during a rebuild lost its turbo. I was told it has a Marlin Crawler dual case. It does have twin sticks but I'm unsure if the specific model and gearing. The 3rd member is 4.88 geared but I don't know about the crawler. The stock W56 transmission has 2.28 for low, how do I identify what gears are in the Marlin Crawler case? Do I have an Ultimate Crawler set up? If the truck started out as a turbo, then the drive train should be 23 spline drive shafts. How can I identify 21 vs. 23 spline? Any help would be much appreciated.

[gnob]

There were no factory manual turbo 4runners. If you w56 odds are you are 21+21.
You can check gears by driving it. You will have to pull cases to check spline count.

[redneckcustoms13]

Look at your bellhousing. If it has a round rubber plug on the bottom it is a turbo trans (r151f). If it is a r511f trans the first case(crawlbox) will absolutely be a 23 spline input. As far as your 2nd case it could be 21 or 23. You will only know by taking it apart.

If you do not have a r151 then you have a 21 spline input in the front case and are running a g or w series trans.