i broke what the transmisson guy called the sunshell, lost 2nd 4th and reverse.

It's a computer controlled pressure solenoid. Maybe there's something wrong with your car other than the transmission.

so i pulled to pan and valve body yesterday. i had no problems with the trans but am in the middle of a build and decided to put the shift kit in while i have the trans out. i started to take off the accumulator housing and it was dented underneath. it looked very odd with a bunch of dents in it right under the housing. so i pulled the seperator plate and the 3-4 accumulator piston is in about seven different pieces

My first trans problem with the 4l60e was a busted planetary and the drum with the input shaft. Also had a rearend go out at the same time so couldve been the shock from that.Second time was just the normal 3-4 clutches , just stockers.
Which brings me to my newest problem.A year after my last build, Which had the z pack clutches,band,and billet servos, i lost 3-4 again.I lost them under wot on the highway either shifting from 2-3 or 3-4 i didnt pay attention.
Any common places that could cause this?
I am thinking about upgrading a few more parts while im in there like the sunshell and such and was thinking about running the red altos and kolene steels this time around. Are these better for a street strip daily driver that beats on it allot or would something like the blue plate clutches be better?Also What about the pumps with the 13 vanes?
By the way this is a great sticky, very very informative

Oh boy. I know the tranny was weak before it went, but man. We're going to replace it because it definitely doesn't work anymore. Then I guess we'll have to narrow it down with my dad after.

I'll be looking into these computer controlled pressure solenoid. Possibly a bad computer chip, or sensor?

I know this post is way late but just for reference in this sticky, The 96 4l60e has a sunshell with the stronger gear and weld and redesigned thrust washer. I bought a "Beast" sunshell and it was exactly like the 96 GM unit. I'm not sure about the part in your 94 though?
Just thought I might save someone some $$$.
Wow, I haven't been on this site in forever. I'm glad to see it still up and running. Hi everybody!

The sunshell that you "saw" was the "Beast" type. They were never available from GM. The first change to any GM sunshell was the introduction of the needle roller bearing style of sunshell. This needle bearing took the place of the thrust washer that made contact with the output hub and sunshell. The later oem sunshells (somewhere around 2003) of both types started to get "heat treated" at the splines where the low/reverse sun gear connected to the sunshell, this was the "weak point". Since then the oem "heat treated" sunshells have proven very successful. I have one in a mid nine second 1996 Firebird (1.24-1.28 sixty foot times) that has well over 2,000 passes on it, without stripping or breakage. There are advantages to the late oem sunshell over the "Beast", they are lighter, balanced (the Beast is not balanced), and lastly, less in price. I have not seen one of either oem units break or strip, and have not seen a "Beast" go away either. Either are good choices. Dana

Greetings group,

Need information advise. I own a 94 Z28 with 169k miles on it that I've had for 8 years. On recommendation from my mechanic, had only changed the fluid/filter on the tranny once the whole time I've owned it. Recently, I took the car in to swap the Optispark (for the third time!) and when I got it back, I started noticing delayed shifts to 2-3 under accelaration. The tranny fluid is black and smells burnt, so the mechanic is recommending changing clutches. Being that this is all of a sudden and occurring just after I made a major change (the optispark), could there be some relation, or is this just coincidence and my mechanic is telling the truth??

Thank you for any advice.

You pretty much answered your own question. The transmission fluid being "black and smells burnt", is a sign that something is wrong. The "optispark", had nothing to do with it. Time for a rebuild. Dana

Look at it as a chance to upgrade!

Rich

well i just snapped my 2-4 band and destroyed the sun shell along with the my new 4k stall converter

Well the failure originated in the diff, when it locked up the splines on the output shaft in the transmission twisted together with the splines on the slip-yoke going into the trans. Needless to say it was pretty difficult getting the yoke OUT of the transmission. A come-along hooked through the yoke and connected to the front bumper of my Jeep eventually did the trick and it EXPLODED out of the transmission, almost taking me with it. This, however took place after the Jeep got drug toward me almost 2 feet by the come-along. Really good stuff.

Had the tranny re built in 08 because i lost 3rd and 4th gear, and just last week, i went to launch the car and lost 3rd and 4th gear again, dont exactly know what happened, and havent pulled it apart yet

i burned up all of the clutches in the forward drums, cracked the 10 vane pump, and burned the stock band up, i am now running much better red eagle alto clutches, and alto wide bands

The two sunshells I was refering to are 1- the original in my 96 4l60e, and 2- the Beast I bought. I just bought the Beast as an upgrade but realized it was no better than the original 96 GM unit once I compared the 2 units. I will say both units are much stronger than the older 700r4 design which were notorious for breakage at the weld.