2017 Tahoe Trans rebuild advice?

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TireFire

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Hello all,
I’m new here so hopefully posting in the right place. Made an account to solicit some advice on my current situation.

Our 2017 Tahoe has about 127k on the odo now. Got it a few years back with about 90k and immediately turned off AFM with an OBDII dongle. I don’t think it’s ever had trans fluid changed (no drain on the pan, lol), but it didn’t ever top 195F during my ownership. Yesterday I suddenly had a bunch of neutrals, some grinding noise, and eventually CEL popped. Was able to limp it home. Codes are P0700 & P2723. Dip stick shows some fine aluminum shavings. Assuming TC grenades & took out the pump sending metal everywhere.

I’m resigning myself to the likely scenario that it’s gone (insert blown tranny joke). Found a local place that offers in-house rebuilds of MY transmission, not a swap for a remanned unit. Cost around $7k, gulp!!

TLDR,
1) what sort of upgraded parts should I ask for in the rebuild? I read Sonnax has a good rep but lost in all the details and various parts
2) Any recommendations for a torque converter? Nothing overly expensive but that will handle frequent towing of our boat (7k lbs+). Maybe something with a forged lockup piston & billet lockup plate.
3) do I need a new radiator & cooler? I have the max trailer package and the external one looks like tube & fin but not sure what’s in the radiator? Local shops all say just flush??
4) should I delete the thermal bypass mechanism or just go with the updated part from the TSB (21-NA-199)?
5) any recommendations for a mail order tuner? I have the HP tuner device but not really versed in anything other than loading tune files. I’d like to turn off AFM & perhaps keep the TCC from locking up in low speed all the time and slipping so damn much. Would like to get another 100k from the rebuilt trans.

TIA, all!!
 

tom3

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Son just went through this with his Sierra, just over 100k miles too. Looked around, got a lot of referrals from his buddies. Took it to a transmission only shop down on the river. They put in rebuilds from a place they always use (not a Jasper), 3 year warranty. Guys says the 6L80 is really helping his retirement these days. But he says all the parts these days are from the aftermarket and are improvements over the stock OEM stuff and he always puts in an upgraded converter, eliminates the thermo valve deal. He also does the programming to eliminate the AFM, set shift points a bit different, and changes the TC lock up deal to what it should be without all the slipping. Truck is some different since the change out - and for the better. Two day turnaround. Full price all in was $5100. Son is a school teacher with 3 kids, that hurt.
 
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TireFire

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They should call it generous motors for sure. At this point I’d be happy with the relatively low price tag of $5,100. What area are you in. I’m in Western WA on the peninsula
 
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TireFire

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Bueller??

Trans shop just called and after pulling the pan confirmed that it needs a complete overhaul. $7,500 Fakkkk.

They said they use upgraded TC and bypass the thermostat on all rebuilds but recommended against tuning the TCC differently. Wonder why??

For those who’ve had theirs rebuild (not swapped in a reman), what upgrade parts did you request? Anyone have a drain plug added to the pan?
 

NickTransmissions

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Bueller??

Trans shop just called and after pulling the pan confirmed that it needs a complete overhaul. $7,500 Fakkkk.

They said they use upgraded TC and bypass the thermostat on all rebuilds but recommended against tuning the TCC differently. Wonder why??

For those who’ve had theirs rebuild (not swapped in a reman), what upgrade parts did you request? Anyone have a drain plug added to the pan?
See my 6L80 Information Thread for upgrades (link in my sig) - I made that thread specifically for DYIers and other intereted parties to simplify and bring clarity to dealing with these transmissions.

Upgraded TC, Sonnax Zip kit (or Transgo repro kit), Sonnax billet 4-5-6 clutch hub, piston kit, 1-2-3-4 billlet piston, 3-5-R hp apply ring, etc.
 

tom3

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Grandson has an 06 Silverado that has what looks to be a factory drain plug on his trans pan. Never seen this before, but a real common sense item. I put drains on any of my vehicles when the warranty is out. Just find a spot, usually near the magnet, drill a hole, weld a nut inside, flange head bolt and a gasket. I can still make a mess though.
 

NickTransmissions

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Even with a better TC, I would insist that the TCC be programmed for zero slip, and only activate in 4-5-6 gear. There is no reason for lockup in 1-2-3 gear, plus you will still wear out the TCC - it'll just take longer with a good TC.
Yep, a good tune should compliment the mechanical overhaul when it comes to these and other clutch-to-clutch transmisssions
 
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TireFire

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Even with a better TC, I would insist that the TCC be programmed for zero slip, and only activate in 4-5-6 gear. There is no reason for lockup in 1-2-3 gear, plus you will still wear out the TCC - it'll just take longer with a good TC.
Any recommendations for a mail order tune to do that? Or do you do this yourself with HP Tuners? I read that eliminating lockup in the low gears is key, and maybe also increasing min. lockup speed in the taller gears in addition to allowing zero slip?
 

mikeyss

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Any recommendations for a mail order tune to do that? Or do you do this yourself with HP Tuners? I read that eliminating lockup in the low gears is key, and maybe also increasing min. lockup speed in the taller gears in addition to allowing zero slip?
I had blackbear tune my transmission. A lot of the members on here have their tunes with great results.
 
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