Whahapan33

iTrader: (1)

Hey what's up guy's? First post and first rebuild. So I have an LC9/4L60 that needs some attention. Tranny has a grinding sound in first and reverse, since I wont have the funds to do a complete swap to a 4L80 or 6L80 I'll be rebuilding the trans. Rebuilt kit, vette servo, shift kit, and a few other things. I was looking at the Circle D converters, thinking a 2600-2800 depending on cam choice.
On to the motor this is going to be fun since I've never tore a motor apart, just swapped a new one in. Since this motor has DOD I'm going to get rid of that with either a kit or buy parts separate. The cam's I'm looking at and undecided, so need advice on are the BTR stage 2 or 3. Also going with SE LT's maybe their true duals kit.
Now to the part I get lost on compression. So I've read that the 5.3 has a 9.5-9.6:1 ratio. Then I read that the 07+ LC9 has 9.9:1 if this is the case would the flat top pistons be what would get that compression to 9.9?
Lets say I have 9.9 with flat pistons how much milling on my 799 heads would need to be done to get me around 10.1-10.5?
Same with 9.5-9.6, if I don't have flat pistons that would be one other thing I'll get for my engine build plus whatever else I need to get up to higher comp.
I'm also thinking about replacing the main and cam bearings since the motor has 180k on it, and has an oil leak in the rear. Lets not forget a tune this would be a little tricky for me, places that do that is about hr away. I've thought about doing this myself but it might be a little over my head. I don't tow with this burb every now and again I'll pull another vehicle when stuck, dunno if that would matter with converter choice or not.
I believe that's all I'm thinking of doing and would appreciate any and all help with some of these choices.
Thanks

Wolftrk99

iTrader: (5)

The gen iv 5.3s have flat top pistons already. As far as the trans goes by the time you rebuild and upgrade it, you could very well have more than a 4l80/6l80 swap in it! My 6l80 swap including building the trans and having to buy hard parts, cost something around 1800-2000, the 4l60 i built for my 99 was closer to 2800 by time it was all said and done... grabted i do have left overs from the 4l60 build but i have them fron the 6l80 build as well!

At 180k if youre going through the engine, replacing all of the bearings including the cam bearings would be a wise decision, if youre deleting the afm anyway deleting the relieve valve in the oil pan would be a smart choice too!

Whahapan33

iTrader: (1)

Thank you
How hard is it to rebuild a 6L80 compared to 4L60? I've priced 6L and I could get one with 80-90k for $1700. I could do this for now then later have it rebuilt in a yr or two. I probably should ask about a core one if I could even get a core tranny. Plus all other misc. I need for the swap. Shortening and lengthening drive shafts, shifter, shift linkage, what else was there. I really wasn't going to go all out on the tranny rebuild like the heavy duty stuff just a few though. Basically all I was going to do was rebuild kit, servo, shift kit, line pressure boost kit and sonnax sun shell and maybe change the planetary gears to a 5 gear instead of keeping the 4 gears. You know after hurting my head with all this reading on here I don't think I came across replacing the relieve valve in the oil pan. only blocking holes if the person planned on still using the afm valley plate.

Wolftrk99

iTrader: (5)

Are you 2 or 4wd?

Whahapan33

iTrader: (1)

Its a 4wd

Wolftrk99

iTrader: (5)

6l80 swap would require at least an input shaft swap on the transfer case, though some of the 07 suburbans and tahoes had np246 rather than the magna transfer cases, which makes finding the input shaft a little easier! Along with either a wiring harness or a dummy tcm and the harness from true blue... i ended up going with a harness from a 2011 and had to build a harness for the fpcm and the bank 1 downstream o2! Given the choice id go with the 6l80 again!!! They are actually easier to rebuild than the 4l60 imo! As far as the swap goes physically the 4l60 and 6l80 and 1/8-1/4" difference in length so everything bolted right up, didnt even need to change the shifter cable, only thing i havent gotten squared away yet was the tu/td and that i had wirking temporarily

Whahapan33

iTrader: (1)

Yeah I've been reading yours and iamkeniff 6L80 threads. Haven't gotten through the whole threads yet since they are long lol. I should probably look more for a 6L80, input shaft and harness.

Wolftrk99

iTrader: (5)

Which transfer case do you have? If you have auto trac you may have the np246, which if you do, you need the 32 spline input from a 4l80 mated np 246, if you have an nqh or one of the magna 3023 transfer cases, you may be better off finding a used t case, noone has had any luck lately trying to get the input shaft for them from gm, or anywhere else for that matter! As a matter of fact there was a thread about it awhile back...

Are you reading through my yukon build thread or the thread i started specifically about the 6l80s?
There is a lot of unnecessary crap in my build thread, lol!! I tend to vent on occasion...

Wolftrk99

iTrader: (5)

Oh as far as the harness is concerned, the np and magna transfer cases use the same connectors on the encoder motor and vss so you could luck out and find a harness for a 2009 and be good to go, if i had been able to find a vin for one with a 6.0'or 6.2, 6l80 autotrac nqh i would have saved myself a but of money... just make sure the harness you get matches the fuel system you have, flex fuel vehicles have a fpcm that the connector is different on and if you arent careful you will have to build a sub harness for it!!!

Whahapan33

iTrader: (1)

I saw this and thought crap I have the odd ball case. But I cleaned up my tag and saw<br/>



So I'm assuming it's the np246
So part number 19019 is what I would need