A 5 gear planet will not change the ratio. 4l65 and 4l70 had this planet carrier for increased strength. It will retro into the 4l60 but no ratio change. If you want the ratio change, it is the Sonnax unit with 6 planets and 38 tooth sun gear.

 

Thats what i meant, thanks for that!

 

Well I desperately need Sonnax part # 77733-10kb, and of course NO ONE has it...If anyone has a lead on one, please PM me.

And the gear change wont happen as I found out they are more for turbo LS motors to keep them in the powerband according to the builder.

Uh, just my luck

 

A quick check confirms what you say - "Out of Stock" by many. However, JEGS does not indicate this. This may change when you try to check out but I was able to "place in cart".

As far as the 284 ratio - I think your builder has to reformat his hard drive. Sonnax has probably sold many to other than LS owners with the same goal.

EDIT: Ebay shows several available.

 

Funny im on Jegs now and i see the same..Might try to order. I also emailed sonnax just to see if they had a possible ETA on them.

And I didnt mean he said was only for LS turbo. The guy had me on the phone an hour discussing it all. At least for once I feel the trans is in good hands.

 

I looked at ebay, all the ones i saw were -12kb.

Well Jegs let me order it with a direct ship Feb 20 something...Summit wouldnt even let me do that. So I guess ill see. Not in a hurry obviously, so I guess I hurry up and wait lol.

Thanks again

 

^^^^^^^^ I just noticed this also and was going to "edit my edit".

 

Thanks again for your help! If by chance you came across one, let me know!

 

Yes.

 

Emailed Sonnax and they actually got back to me. He said GM had a "part disruption", and that they only just received the drums at the beginning of the year, then they go through multiple process before shipping. So the ship date of end of February should be correct. At least some light at the end of the tunnel!

 

I just learned of something. If the JEGS order doesn't pan out, there is another upgraded drum that appears to be as good as the Sonnax one

Mason Smith 4L79.

 

Hmmm...Interesting. Hell of a price difference as well..

 

You would have to price compare. The Mason Smith comes loaded but no shaft. The Sonnax comes with shaft and collar but no frictions or steels.

 

Will stick with the sonnax, but thanks for the info!

 

I updated my long thread "just for the hell of it" but figured i would here as well...still waiting om the sonnax part. But in meantime i also picked up the heavy duty reaction shaft from sonnax. Other part i should have in April according to sonnax. I decided against the sonnax 6 planetary set with the gear ratio change. Dont need it. The builder is putting in the 5 planetary set front and rear.....so now its just a waiting game

 

So this has been fun.

After having the Sonnax input housing on order (and paid for) since Jan 2026 I cancelled the order. Once a month id email them and ask for an ETA and it was always "next month". Enough.

So I ended up talking the the guys at 4l79.com and went with their 4l78 setup. This is not the strongest one they offer, but is good to 600 hp. Only reason I went this route is the 4l79 setup they have is patented by them, and it takes their own frictions and steels. I was assured the parts for it will always be in stock, but my luck if anything was to happen and I needed new frictions and steels, they wouldnt be available. The 4l78 setup takes the regular size frictions and steels. They also told me they have a lot of drag cars running the 4l78 setup with no issues. So thats the route im taking.

So they dont have the hardened input shaft however. They told me if I can get one, ship it to them, and the will press it into the new setup with the input sleeve as well no charge. So apparently I found and bought the only Sonnax hardened input shaft in the country. $800. Ouch. Its on the way to them and they said 24 hour turnaround and its on its way back to me. Once I get it, im hauling *** down to my builder with the new parts.

My goal is to have the car back together by mid May. And im gonna drive the **** out of it. There is a Corvette show June 6th near me, and I plan to be there.



Im going to continue this saga on my "just for the hell of it" thread. Im hoping for no more drama from here....

 

You made a good move going with the drum you did for the reason you stated. TBH, before I researched your thread, I had never heard of this company or this product.

 

Thanks. Yeah, its a little stressful sending a $800 piece to a place ive never been to or heard of, but I did talk to them for 15 minutes on the phone and felt better about it. Plus I google earthed them to make sure it wasnt some dudes garage lol.

Hopefully in 2 weeks ill be installing it. I NEVER wanna pull this transmission again. But the one bright thing here is that ive learned more about auto transmissions (especially this one) in the past year then I have in my 52 years. So there is that!


Oh and I forgot, the stall speed has been increased by 300-400. So that should put me at 2900-3000 roughly.

 

200 miles so far. All good. Extremely happy,
trans working beautiful and the little more stall is very nice. I posted on my other thread but figured id update it here as well.

 

I had my Trans problems.
Matter of fact that is the only part that I paid to have done.
My $300 Ebay used Trans lasted 7 plus years with just the servo Failing.
I have a Built 700r4 with shift kit now I paid someone to do and he had to do it again after 100 miles due to the shell Failure.
My trans goes out again I won't take to shop I will rebuild myself or get another car.
I feel more sure with doing a rebuild myself with the videos than another shop.