Trail-Gear dual case coupler failure

My Trail-Gear trans to t-case coupler failed on the highway in Colorado and left us stranded 1700 miles from home. It also destroyed the output shaft on the transmission. I noticed the day I put it on, the fitment was much looser then the Marlin Crawler coupler on my 4runner that lasted 10+ years and still looked perfect when I sold the trans. The Trail-Gear coupler was about 6 years old. Trail-Gear declined to warranty or offer a discount on a new coupler. My truck has never had bigger then 35” tires and the stock engine. This failure was due to wear not brute force.

Kyle at Marlin Crawler was able to sell me just a new coupler from one of their kits and take some measurements to confirm it would fit with my trail-gear adapter plate.

 

Well, I'm glad I bought the Marlin Crawler then. Sorry for your problems. Haven't installed mine yet.

 

The way those splines are worn down would make me wonder if the adapter plate isn't machined right (not on-center, putting the shaft & coupler at an angle). I'd pull that back apart after a bit and see if the wear is continuing... If so, the adapter plate might be to blame.

 

The loose fit did not make you think??

I think getting 6 years in that case was some great luck on your part.

The amount of movement in the splines just wore things out.

I sucks you were so far from home when it quit .

 

I originally tried to order all Marlin parts but they were out of stock for several months. I thought of trying to get my old coupler back but it was too late as I had already sold the trans, 3.0l adapter and coupler to a friend who had already installed the parts. In preparation for the trip I rebuild the dual transfer cases with a new coupler and input because I have heard of those stripping out before but not trans to t-case couplers. The actual dual transfer case setup is 16 years old. I ran it 10 years in my red 4runner before moving it to my Tacoma. The failure did not damage the transfer cases at all. Only the coupler and transmission output.