I have a 1980 with a broken L43 and I'm replacing it with a W56-B that I just bought. The W56 came with the transfer case which I believe is 21 spline and my transfer case in the truck is 21 spline. I was thinking about getting the adapter to do a doubler. I've been reading and searching about the different ones out there;
Marlin seems to be the best but is over $700 and it out of stock
inchworm is not around anymore
Trail gear doesn't seem to have a great reputation
Advanced Adapters kit is in stock at summit racing for $377 and on the web site it says " The new Tx2 double bearing design"

I read that people complained about the bearing in the AA but said it was the same as the marlin MC05. Most of the post I read are from 10+ years ago and I wanted to know if there is a early version of the AA unit and then this one with the Tx2 double bearing.

My plans are 63"/RUF, W56-B dual 21 spline top shift, 4.88 or 5.29 gears and 34x9.5x15 - 35" are the biggest I plan to run.

I've never had problems with AA stuff before but I haven't built anything in 10+ years, buy it or look for something else?

 

Interested on what you find out. Marlin shipping and inventories have fallen down hill recently.

Heard new TG cases are better than older ones but.... no one ever brags about getting skunked by TG.

AA has a great reputation. Give them a call. Doesn’t obligate you to buy.

 

Im running all AA stuff in my 23spline duals behind a v6 (so two adapters) and very happy with it. Have always had great customer service too when I called them.

 

Thanks for the responses, I am leaning toward the AA adapter. I'm trying to see if I can find it for a better price then $377 at summit racing which isn't bad but I'm trying to find deals on stuff if I can.

 

That may be the best price. Plus with summit you get free shipping.

 

PolyPerformance has it for the same price but they always have an additional 10% off code available.