Has anyone used a sonnex smartshell on their tranny rebuild? I'm weighing my options for when I dive into this & for about $20 more than the Beast Sun Shell it seem like a good deal & it's lighter than the beast. I was going to go ahead & replace the one in it even if it's not messed up since it's a known weak point in the 4L60E.

2001 Blazer 2wd.

 

The factory sun shell was upgraded to a stronger one starting on the 2000 models. Yours being a 2001 the sun shell is no longer a weak point.

 

I am not A big fan of the beast. In some builds I have had it rub the case. The only change that was made to the reaction shell was the removal of the 4 tab thrust washer between the front planet hub and shell. And replaced with a bearing. The Sonnax shell is great as it reduces the force that is put on the rear planet captured bearing by the sun gear and also the splines are heat hardened. There are several aftermarket companies offering a heat hardened shell that is just a durable in applications that do not over stress the gear train. In passenger cars,light SUV's I use a hardened shell. Any other build such as full size pick ups,high performance builds or any vehicle used for towing or plowing. If it is a standard application build I would suggest to spend extra money on other up grades as new boost valve, aluminium accumulator pistons,bushing kit.

 

I thought that started in 2002. Good to know. I'll just run it & save myself $80 to spend on it elsewhere if the rear planetary still looks good. I did like the idea of the smart shell taking pressure off the rear planetary, but I'm not planning on hot rodding this thing. I'll flat tow a light weight dune buggy on trips occasionally & jerk a small trailer around once in a while but that's about it.
Thanks for the tips about the boost valve, pistons & bushings.