GM 6L80 Transmission Information Thread

[SpyShops212]

Hi @SpyShops212 , I'm not super familiar with them, haven't gone hands on with one yet but have researched them (and the 8speeds) as I may take one or both transmission families on in the near future. From what I understand, the 10-speed has some improvements that address some of the pattern failures seen in the 8L45s/90s but like all transmissions, will have it's share of warts.

Are you located in or around Vegas?

I am in Houston. I wanted to know if you could tell when you have a Nick supped up transmission or does it last longer? Well maybe that is a good thing you don’t have experience yet with the 10-speed. Does this mean that it is such a good transmission that you have not had to touch one yet.

 

[NickTransmissions]

If I were to replace the torque converter with a better-than-OEM aftermarket unit, would I notice it in day to day driving, or would it just be a reliability upgrade?

Hey Charlie,

It's more of a reliability upgrade than anything else; keeps you on the road vs on the side of it. I'd definitely replace the TC with an upgraded one - wait until you see the deep dive video that i'll be shooting/publishing in a couple weeks or so about those POS JMBX converters...

 

[NickTransmissions]

I am in Houston. I wanted to know if you could tell when you have a Nick supped up transmission or does it last longer? Well maybe that is a good thing you don’t have experience yet with the 10-speed. Does this mean that it is such a good transmission that you have not had to touch one yet.

Gotcha...I don't ship transmissions or build them from folks outside driving distances given the cost and logistical complexities dealing with a transmission that may have to come back for any reason.

As far as me not seeing them has much more to do w/me not actively promoting/advertising my services for that particular unit since I don't want any potential customers to be my 'test cases' when it comes to learning them. when I decide to take on a new transmission family, I'll purchase two or three cores, usually from different parts of the prod lifecycle (i.e an 'early' unit, 'mid-lifecycle unit and 'late/current year unit') and from different vehicle models/sub-models so I can learn as many of their their ins and outs as possible while accumulating an inventory of hard parts. No timetable as to when I may take on the 8 or 10 speed GM and Ford transmissions as I've been slammed w/four and six speed work...

As far as telling by shift quality/feel/performance whether or not you have one of my transmissions (or one from any knowledgeable builder) that will depend on the unit...95% of upgrades that to into the 6L80/90s are intended to improve reliability as opposed to change the way it shifts/feels to the driver. But a few choice mods can improve shifting characteristics but much of the 'seat of the pants' performance upgrading is actually done via tune. This is true for all late model units as so many of them are designed to be very sensitive to shift strategy programming vs mechanical tuning like the legacy three and four speed transmissions.

 

[S33k3r]

@NickTransmissions Where are you located?

 

[strutaeng]

@NickTransmissions Where are you located?

I believe in another thread he said Las Vegas area...

 

[NickTransmissions]

Yep, Im in Vegas.

 

[blackelky]

I have a 2012 tahoe at 96k miles should i have the dealer do a reverse flush or change filter and fluid instead?

 

[petethepug]

XLNT question. I wanna know some mindset on that too. Don’t forget your at the pivotal 100k major service. There’s several things tied into the trans service, especially if 4WD. Once the trans is removed for service labor costs plummet because there’s access to everything below …

Motor & trans mount, oil press sensor, exhaust manifold gaskets, front diff mounts (bushings), Torque converter, rear main seal, pan gasket, 99¢ oil pump o ring.

If any of the above are on your list to repair, order the parts from rock auto or similar when holiday sales are occurring and save crazy $ vs your tech sourcing them locally for you. Have it all done at once and save 1 or $2k depending on where you take it.

It’s literally a once in a 100k opportunity of a lifetime that will pay you back for the next 100k miles.

 

[DaveO9]

Similar questions here, too. My '13 has 197k on it. Transmission shifts fine, no issues at all, but my plan is (was?) to do a preemptive torque replacement/upgrade, pan drop, and probably put a Sonnax zip kit in it. But today I called a local trans shop with a good rep (I've had work done there before too, good experience) and his response was less than encouraging. He's saying the 6L80 seldom lasts that long and, though it's a good thought to do torque converter preemptively, he said the same thing could happen in reverse, i.e. clutch packs in trans fail and then ruin the new TC. So he advised against it and said run it till it dies.

I guess my next step is to make sure it's the original trans. (that was shop's first question to me) I'm going to see if I can get numbers off it and do some digging before I go any further, but I'm not sure I want to run it to death. That's just not the way I like to do things, and I wouldn't trust it on long trips.

Any thoughts? Am I being steered wrong? I'd still like to do the TC replacement and have the budget for it, but not if it's going to go to waste.

 

[NickTransmissions]

Similar questions here, too. My '13 has 197k on it. Transmission shifts fine, no issues at all, but my plan is (was?) to do a preemptive torque replacement/upgrade, pan drop, and probably put a Sonnax zip kit in it. But today I called a local trans shop with a good rep (I've had work done there before too, good experience) and his response was less than encouraging. He's saying the 6L80 seldom lasts that long and, though it's a good thought to do torque converter preemptively, he said the same thing could happen in reverse, i.e. clutch packs in trans fail and then ruin the new TC. So he advised against it and said run it till it dies.

I guess my next step is to make sure it's the original trans. (that was shop's first question to me) I'm going to see if I can get numbers off it and do some digging before I go any further, but I'm not sure I want to run it to death. That's just not the way I like to do things, and I wouldn't trust it on long trips.

Any thoughts? Am I being steered wrong? I'd still like to do the TC replacement and have the budget for it, but not if it's going to go to waste.

I agree w/the shop in that putting a new TC on a 197k trans isn't the best way to go...

At 197k, I'd yank it out for overhaul if you are in good position, financially and logistically to have the work done now. If you want to save money and you have a 2WD, you can pull that 6L80 out yourself in about a half hour-40 minutes. Just make sure you're on a level surface, vehicle on all four jack stands (6 tons each) and something to lower and raise the trans back into position (most use a floor jack though you can buy a trans jack which makes the job a lot more efficient).

Alternatively you can drive it until it croaks but may do some damage to hard parts...The major hard part that you don't want to do damage to is the rear planetary carrier set, which is a Ravigneaux design and can be somewhat expensive to replace. The torque converters are pieces of ***** and must be replaced with a converter that features a clutch that's at least .050" (my stuff gets a .070 thick Borg Warner high energy converter clutch, except for real HP stuff which sees a multi-disc converter w/a billet cover. So next time you talk to him, find out what converters he uses and how thick the converter clutch is that comes inside.

I'd also consider replacing your radiator unless it has been replaced within the past 50k or so (buy an OEM GM part, no aftermarket radiators) - the last thing you need is for the internal transmission cooler to fail and leak water into the case under high pressure. That would be catastrophic and require you to literally order a brand new transmission (or find another core and rebuild that one). Flush the lines also (shop will do this if they are doing the removal and reinstallation).

I'd say it's highly unlikely your current transmission was swapped at any point in the past but anything is possible.