Topic: Crawler Problem

[Duckman]

Just purchased a yota that has a crawler box in it.  He says that the crawler is an earlier Marlin version but the adapter says AA on it.  Anyway, the low range gear inside (the biggest one) that has the synchro teeth on it for LOW engagement is done.  The needle bearings are crushed and welded to the gear.  So the low range gear and the spud shaft that comes with the crawler is all muffed up.  I know it will physically fit but is it acceptable to put a set of 4.7 gears in the front crawler and keep the rear case 2.28?  It is all 21 spline stuff behind a stock 22re.  I am not hard on the skinny pedal but is this just a waste of money to buy the lower gearset.  I might as well because I need a new low range gear anyway.  Also, can I get a new spud shaft or do I need to buy a whole new crawler kit?  Thanks for the help

[yotaboy79]

give marlin a call he will answer all your questions

[BigMike]

So you are saying that a factory 2.28:1 low range gear is messed up? Or does that Crawl Box have a 4.70:1 gear set in it for some reason?

The problem with putting the 4.70:1 gear sets in the Crawl Box in a 21-spline setup, is that the torque leaving the Crawl Box is multiplied so much that by putting that much torque infront of a 21-spline factory input gear will cause it to break/yield. The 21-spline factory input is "fused" between the splines and the seal surface, and the physical size of the fuse is not sufficient to handle the torque coming from a 4.70:1 gear set.

You do know need to be heavy on the throttle for torque to increase to the point of failure. You could be at idle engine speed, and if you get the truck in enough of a bind, the applied torque throughout the drivetrain system will undergo rapid growth, and will break at the weakest link, in this case, the 21-spline factory input gear behind a 4.70:1 Crawl Box.

Regards,
BigMike

[kneedownnate]

No, you wanna run the stock gears in the first case and lower gears in the rear case, unless you like breaking stuff!

[89 toy]

buy a 4.7 gear set put it in the rear and take the gear set from the rear case and put them in the front.

[Duckman [OP]]

thanks for the input.  It seems like the 4.7 gears in the front case is going to cause more trouble than they are worth.  I will just get a junkyard case and pull the gears out of it and put them into the crawler.  Lots of guys run klune reductions in there jeeps but it looks like the input shaft on other tcases is much bigger and has more splines.