Since the sun shell is a common point of failure, especially in pre-2003 4L60E, the various options are often discussed. While I am no trans expert and therefore in no position to recommend anything, I have taken measurements and pictures of a stock sun shell from a 2001 4L60E, The Beast and the Sonnax Smart Shell which might interest some.

I have recently posted some of this info in other threads, but thought it best to start my own. I apologize for any replication. I am primarily comparing The Beast to the Sonnax Smart Shell.

First here are the weights:

Stock 2001 = 42 oz (2 lbs, 10 oz)
Sonnax Smart Shell = 48 oz (3 lbs)
The Beast = 58 oz (3 lbs, 10 oz)

Here is a bottom picture of The Beast (left) and the Sonnax:



The Stock 2001 and the Sonnax have a thickness of .114":



The Beast has a thickness of .149:



Everyone has heard of The Beast, a popular and proven upgrade of exceptional strength. However, a few people complain that it has given them vibration in 3rd gear, presumably because it is not balanced. On the other hand, my local trans shop has used the Beast in 50+ stock rebuilds and never had a complaint.

The Sonnax Smart Shell is a 2003+ style heat treated GM unit reinforced with a bottom plate to both strengthen it and support a unique torrington bearing. Due to the thickness of the bearing, a shorter custom roller clutch race is also supplied:





In the above picture, the stock roller clutch race is on the left, the custom Sonnax with the torrington bearing on the right.

In the stock setup or even with The Beast, the significant lateral force from the front planetary is transmitted to the sun shell, then to the sun gear and finally to the small-ish torrington bearing inside the rear planetary. Some claim this is the root cause of rear planetary failure - the small inside torrington fails which then severely overheats the pinion assembly. The unique bearing under the Sonnax Smart Shell supposedly solves this by transmitting the lateral force to a custom roller clutch race and then to the rear planet carrier which has a much larger and stronger bearing.

The following pictures show that in the stock setup there is a gap (about 0.028") between the bottom of the sun shell and the plastic washer which sits on top of the roller clutch race:





Everything is clearly sitting on the small bearing inside the rear planetary. (And Yes, I did remembered the plastic washer under the sun shell.)

On the other hand, with the Sonnax there is no gap as the unique torrington and custom roller clutch race are taking all the weight:



The Sonnax assembly is designed so that the entire package is the same height as the stock one. These pictures show that my Sonnax is actually a few thousands shorter than stock. (The actual height on my caliper is meaningless, only the difference matters.)





With either The Beast or the Sonnax, you can optionally use the new style Reaction Carrier Shaft with a torrington bearing to replace the old style four-tab washer between the front planetary and the sun shell.



This is a picture of the new Reaction Carrier Shaft (on left with torrington bearing) and the older one which uses the four-tab thrust washer. (Note this is upside down from how they are installed when building the trans.)

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I hope at least a few of you found this useful and/or interesting. I will be happy to take and post any other requested pictures before I perform my final assembly. Again, I'm no trans expert and primarily wanted to post measurements and pictures of the differences between these sun shells.

 

Been following your information.Very nice.Question,is the torington bearing style OEM in anything or just aftermarket?

 

Thanks. If you mean if torrington bearing between the front planet and the sun shell, that is the OEM GM design beginning with some models in 2001 and all 4L60E by 2003 (as I understand it). This GM change involved a new design sun shell and reaction carrier shaft with the new torrington thrust bearing.
If you mean the torrington bearing underneath the Sonnax sun shell, that is a custom size, but is part of the Sonnax kit.

 

So if I wanted to swap my Beast out for the Sonnax what all parts would I need to replace. Chasing down a vibration in 3rd gear only.

 

You only need the Sonnax Smart Shell - it comes as a kit with the sun shell, the bearing and the custom roller clutch race. That is the only hard par you need to buy. I bought mine here for $76:

http://www.transmissionpartsusa.com/...-07774902k.htm

You also need a new pump-to-case gasket, o-rings for the servo (which must come out), the pan gasket and probably a few more I am forgetting. An "Overhaul kit" has all those gaskets and o-rings for about $25:

http://www.transmissionpartsusa.com/...-000035034.htm

This assumes of course that your teflon seals are all in good shape.

 

I know there are still doubts about exactly how strong the Sonnax Smart Shell is. So, here is something I just noticed...

While I am no fan of PATC (they seem arrogant and have a horrible website), they are now advertising a 4L60E built to handle 1000HP !! Before you get too excited, it is priced at $5800. They list all of the included parts and it includes the Sonnax Smart Shell and not The Beast.

Here is my thread on it:

https://ls1tech.com/forums/automatic...l#post16274722

 

Yes we have also been using the sonnax smart shell for quite some time they seem to be very strong! MaddodLou

 

When we rebuilt my 4L60E I got the roller thrust bearing with it also and I didnt recall any gap in it. The thrust was taking the weight it was suppose to.


And also I order the billet servo also. We could never get that thing in there with out burning the band up on it. I still have it but we put the stock back in it and havent had any problems....Is that something I should look into trying to get back in it?

Patrick

 

good info

 

The sonnax smart shell is an excellent piece. I have spent hours comparing it with the beast sun shell. I trust sonnax design and I have personally seen these handle 1000hp. I've had a few talks with Greg Nader and I shared some of my opinions on it. Also used their prototype as a test subject some time ago. I would recommend the Smart shell to anyone, whether you're chasing a vibration or not.

 

Thanks for this post! So what is the benefit of the new style Reaction Carrier Shaft with a torrington bearing?

 

I'm not a materials engineer and therefore can only assume that a ball bearing (a torrington is a flat ball bearing assembly) reduces wear and increases reliability.

Note that this newer style reactions carrier shaft is ABSOLUTELY necessary for the 5-pinion planets that GM is selling now. See my post #12 and others in this thread:
https://ls1tech.com/forums/automatic...n-planets.html