I've seen some for the T1N, but I imagine it's going to be impossible to source something for your axle.
With that said, have you tried driving it offroad? I have read that it does fairly well offroad when you turn off the ASR.
And I followed that, to this :Just came across this...........................
http://www.expeditionportal.com/forum/showthread.php?p=300363
If you ordered a left axle shaft from Chris in England, you could use it as a pattern for a machinist to copy. Have five made up and use a core charge to receive another "blank" from your customer.Ahhh…simple engineering…for the most part, yes! But remember, the NAFTA Sprinters are different from the World Sprinters. This is a project that we have been working on. I’ve not seen a NAFTA left axle that has the spline that you are referring to.
Thank you, John
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