When did GM upgrade the sunshell

[JayArr]

Can anyone enlighten me on when GM improved the sunshell design? My trans is a 2005 and the sun shell has perfect teeth and no signs of cracking at all, I even inspected it under the shop microscope and it looked like new.

I'm only running it behind a stock 4.2 with no performance adds but it will be towing a 5000 lb trailer.

Do I really need a "beast"?

I think I've read that the early sunshells weren't heat treated but that once GM had a lot of warranty replacements they wised up and made improvements to the sunshell. I just don't know when that cut in or if it's enough for a stock rebuild.

The failure of this trans was the pwm valve with the stuck ball and the burned 3/4 clutches, it didn't have anything to do with the sunshell.

 

[Reprise]

This is the best info I could find...

• 08681518 was replaced with 24221190 on February 1, 2003 for the U.S. market
• 24221190 was replaced with 24229853 on August 1, 2005 for the U.S. market

The links above will take you to where I found the info.

24221190 was the heat-treated version. However, some reported that the gear teeth were still susceptible to stripping.

There was 1 more revision after 24229853. 24243878 is the last one listed; from 11/1/09.

Note that of the GM parts sites I went to, the applications are no longer listed, so the site where I got this info was the only place *I* could find it, at least.

As far as the info on 24221190 still having problems, I found that HERE
There's some other good breakage info there; it's from 2013.

On edit (bc I was in such a hurry and forgot):
24221190 was listed between $212-$250 USD at most sites I saw it on. The others are probably similar. I know the Beast shell that's in mine ran under $150 when it was installed in mine, but that was 5 years ago.

If you're wanting to beef up the part with one of the GM supersessions, and a Beast winds up at similar money, I'd just get the Beast. Sonnax makes a version as well, but I have no idea what it costs. Frankly, I was surprised at how cheap the Beast was, back then (but by 2018 or so, they'd been out for awhile, too).

 

[JayArr]

Thanks Reprise, great info!

So by 2006 the sun shell should have been the 3rd gen 24229853, and it will be heat treated.

It sounds like I'll just put it back, I'm all for upgrades but from accounts I've read by 2005 or so GM solved this as a major problem. That's not to say that sun gears after 2005 never break but they stopped failing prematurely for no reason.

It's an Envoy with a straight 6 towing a trailer, I don't see a good reason to buy the beast or the 24243878, I think the 24229853 will probably serve me just fine.

 

[Reprise]

If you're driving 'sane', you're probably fine with an OEM shell. The one thing you need to do is tow in '3', not OD, unless you're on very flat ground (and BC isn't that flat, from my memory when I drove through it).

The other thing is an outboard trans cooler. But you already know this.

I remember that my 4200 lb (10ft high) trailer pulled with my V8 Envoy like it was nothing on flats (till I got out in the US West). But when I replaced it with a 5600 lb, (11ft high) and drove that from PA > IL, I was definitely feeling the weight, even after I bumped the TBC up one notch. My LWB '03 was rated for 7000 lb, but after 5600 lb, I'd never attempt to go higher.)

Grades, if you have them, will definitely put a strain on your 4.2 with 5000 lb on the back. Doubly so in high summer. Again... you know this. Keep us posted! 🏕️

 

[JayArr]

I'm a 59 year old man driving under the speed limit smoking a cigar and enjoying the view. I've turned into the guy my 20 year old self used to get frustrated at. LOL

I always tow in 3rd with some summits going down to 2nd. Same on the way down depending on the grade. Speed is not an important factor, I can happily drive up a mountainside at 20mph if it keeps everything cool.

I've got a decent external trans cooler installed and the cooling system is all but brand new (rad, h2o pump, thermostat, fan clutch, hoses flushed and filled yearly).

I think I'm good. I'll post up if something horrible goes wrong LOL