pjwollman

I would like to start a new thread and get input on this issue, I previously posted my story about the problems with TCI 6X and lack of engine braking under Opinions on 4L80E converted 6-speed automatics at the protouring.com site. TCI is of no help and they don't care about Pro-Touring cars evidently, so I have been searching and calling other tech advisers ever since I installed the 6X in an effort to figure out a way to get engine braking in electronic bump shift mode. I thought I had found the answer with Sonnax Smart-Tech overrun clutch valve kit 34200-40K. It looked like a good fix and works on a 4l80e valve body for engine braking. But then I saw detailed posts from years ago on https://www.hotrodders.com/threads/6...-4l80e.285594/ which had pictures of the TCI valve body, and it looks like TCI has an extra solenoid in the valve body where the Sonnax Smart-Tech kit would be installed. I am so frustrated as the PCS 6 speed valve body had electronic engine braking and TCI does not, and they will not do anything about it. TCI's advertising on what the TCI 6X is used for which includes Pro-Touring cars is totally misleading as engine braking is lacking.

Simple put is there anyway to make the TCI 6x valve body do engine braking in electronic shift mode?

If not, has anyone put a standard valve body in a 6X with the Smart-Tech overrun clutch valve and just used the transmission as a standard 4 speed with the TCI TCU?

Pete
71 Camaro RS, LQ4

vorteciroc

Unfortunately, the way 6 gear ratios are created from the Simpson planetary gear-set and the Over-drive planetary gear-set...
This transmission can not give you engine braking reliably.

1st gear could have/ IMO should have engine braking.... however the other gears (2nd - 5th) would be synchronous-shifts in a transmission that was never intended for anything other than A-synchronous-shifts.

I have personally experimented with doing what you are asking for... and it requires very specific orificing, spring ratios, clutch clearances, band clearances, and a ton of trial and error for varying power levels and line-pressures.

pjwollman

Thank you for your reply, I wonder how PCS did it. If I did change over to a standard valve body with Smart-Tech overrun clutch valve do you think it would be turned back into a standard 4 speed auto with of course the different gear ratios? Just looking for options.
BTW, I do seem to have engine braking in manual shift mode L3, L2, L1. But my Lokar Sport mode bump shifter really wasn't deigned for that.

vorteciroc

I have not looked at the valve-bodies and control-modules for either PCS or TCI in about 8+ years.

Unless something has changed... engine braking was done by locking the torque-converter clutch.
This is far from ideal unless a multi disc and friction torque-converter is used.

MaroonMonsterLS1

This is because, in the TCI valve body, the 4th clutch is fed oil through the 3-4 shift valve via PRND4 oil.
So, when you downshift to L3, L2, or L1, that oil is cutoff and you cannot get your gear splitting, because, the overruns are applied by D321 oil directly from the manual valve.

The sonnax smart tech kit kills the overrun oil path to the manual valve, and applies it via direct line pressure, and a switch valve that shuts off the oil to the overruns whenever 4th clutch oil is present.
So, there is a way we could get the overrun clutch applied while still using the 6 speed configuration.

Next, you need the low band on in 1st (it would be ok to be left on in 1x) but off in any other gear (but reverse)
You need the front band on in 2nd (and 2x) but not any other gear

The low band and front band, I think we can figure out fairly easily. I'd have to change the TCI setup to alter how the front band release is accomplished, but for the most part, it shouldn't be too terrible.

So, without having one in front of me, I would say it is highly likely that you *could* make this work with modification. However, the shift timing on everything would be a NIGHTMARE.
If I was doing this for someone, I'd be prepared to have multiple separator plates with me, and we would be logging lots of data and prepared to make multiple orifice size changes while at the track testing.
And it would take more than one day. It would just be a real bear.

If you're serious about road racing or pro touring or whatever you want to call it, a beefed up 6l80e may very well be a route you need to explore.

vorteciroc

I can't wait until all the 6L80/ 6L90s are gone and in the junk-yard.
At this point, I would rather set-up a Gear-Vendors unit to overdrive 1st and 2nd gears of the 4L80E, than deal with these modifications alone.

MaroonMonsterLS1

Yes. Well aware shift timing would be the biggest hurdle of this whole operation.
LOT of work just to mimic a 6l80e with all the synchronous shift timing.
Seems really not worth it.

I know you aren't a fan of the 6l80e and I can understand why. But the market is there for them, and the potential is there with some R&D and upgrades to the unit.
Tuning is on the up and up and will make them more reliable and better to drive.

The 6 speed GM is like the 4l60e. It's not going anywhere. It's too plentiful.
Sometime soon people will have them reliably holding HP and we can either be on the upswing or get left behind haha

pjwollman

I want to thank you guys for all the information which is way over my head as I have always been a manual transmission guy. Last night I was driving my car in L2 with the TCC engaged which made the car feel like it should for handling through long sweeper corners, it made me miss my Muncie 4 speed. Being that there is no way to use the 6X value body to make the transmission hold gears in bump shift mode (no engine braking), do you think there is any possibility to go back to a standard valve body with the Sonnax clutch overrun system and just use the 6x gearing as a 4 speed automatic and being able to bump shift it with engine braking or I'm I just dreaming up a solution that won't work? The TCU can be programmed for a standard 4l80e 4speed.

MaroonMonsterLS1

If you move the shifter to D3, you will already have engine braking.
TCI has the 3/4 select valve fed oil from the PRND4 oil circuit. So, when you move the shifter to anything below D4 shifter position, it's impossible to get 4th gear because that circuit is killed at the manual valve.
Any shifter range below D4, feeds oil to the D321 circuit whereas it is unfilled in any range above.
D321 gives oil directly to the overruns and will provide the engine braking you desire.
I see nothing obvious keeping the front or rear band from engaging in this setup.

So, shifter in D3, D2, or D1 should give you the engine braking you want, even without converter locked.

jakeshoe

iTrader: (14)

I warned people about the 6 speed 4L80E's years ago, most likely on this forum.

Why anyone would take a robust design and turn it into a weak transmission is beyond me.

I've had hundreds of calls at this point. "Can you fix this, can you make this work, etc". We won't even touch one.

pjwollman

Yes Jake and others you were right! @MaroonMonsterLS1 said the following on another thread I was posting on about the Sonnax Smart-Tech Overrun Clutch Kit;

For engine braking, here's what you need.
Overrun clutches for all gears except 4th. This can be accomplished with the sonnax kit.

1st gear needs the rear band. This is not applied in stock form unless in D1
2nd gear needs the front band. This is not applied in stock form unless in D2
3rd gear has engine braking by default AS LONG AS the overruns are applied

Looks like I will probably be pulling out the 6x and start over with a purpose built 4l80e and most probably will need to get a good ratchet shifter in order use the lower D1, D2, D3 gears for engine braking and downshifting correctly.

Thank you to all the LS1Tech guys for so much detailed information!

pjwollman

So I am back again to the big decision, which is really painful to pull out and return the 6X or live with it. TCI says that if I want to turn it back into a 4 speed and get engine braking, I can either set the TCU to a 4l80e program or change the value body. I tried running it as a 4 speed using the TCU control and it actual worked fairly well with gear splits that are similar to a 4l60e, however it wasn't shifting into 4th and TCI said "it should" and of course no engine braking in electronic shift (bump shift mode). I'm not sure what they know about their 6X as there are no engineers to talk to at TCI. about the 6X. Also the 6X does at times shift irregular and hard or chirps the tires at oddball times. I would imagine that is the fault of their valve body, not the transmission or electronics. I suppose the advantage of changing the valve body is that I can run the Sonnax VB with the Smart-Tech overrun clutch valve built in so I would get good engine braking with manual downshifts. I would assume the shifting quality is good too, are any of your running the Sonnax VB Part No. GM030?

Lastly, I called Hughes Transmission and they said their 4l80e should have engine braking in electronic shift (bump shift mode), Many years ago there was a Keisler A-41 (4L80e) that was advertised with a paddle shifter and electronic shift engine braking, and also PCS's 5/6speeed valve body did supposedly have electronic engine braking (I still have the literature showing that). So I am not sure how these companies achieved that because if there was a way to build a valve body with electronic shift engine braking I think there would be a lot of buyers out there for it.

MaroonMonsterLS1

There is a way to build it.
Based on what I've seen of the TCI unit, I'm fairly confident I could modify their VB to provide engine braking when the manual valve is in D4 and for all "6" speeds
However...the timing is going to be a bastard and you'll have the exact issues you're having now. Awkward shifts that change with load and rpm.

There is a reason the 6 speed transmissions have the level of sophistication in the controls...they need it.
You're trying to make a 4l80e do the same with 1/4 of the control capability.

If you want 6 speeds. And paddle shifters. Get a 6L80e
If you want a 4l80e...get a 4l80e

it certainly is POSSIBLE...it's just my humble opinion that its not really worth it...to try to do what you are trying to do with the 4l80e

pjwollman

Ok thanks, I sent a private message to see if we could talk about it briefly; here is a link whereby a tech took out the valve body on the 6x to determine the modifications TCI made, I posted the link before, but you might find it interesting reading if you haven't seen it before https://www.hotrodders.com/threads/6...-4l80e.285594/

BTW, TCI had me send back my TCU because they said it should be able to run in standard 4l80e mode and have 4th gear OD. They also said I can run a standard valve body in the 6x and it would turn back into a 4 speed with of course with the different gear set of 2.97, 1.57, 1.00, and 0.75. So at that point I could run the Sonnax VB GM030. I know there has bee some discussions about that from other people.

sgilbert1967

iTrader: (3)

The same reason not everyone runs a power glide, though my 67 came with one...and that I run the 4l80e for years now and the same reason the 8 speed outruns the 6 sped and the 10l90 the 8....its absolutely obvious people want ESPECIALLY on NA engines the the most mechanical leverages via gear splits and amounts, even MPG...the same reason my wifes Hyundai has paddle shifters....
The entire industry moved this direction and people like it...there is a huge difference between an A10 2018up Mustang and 6R80 Gen 2, EVEN when power is equalized.....people want paddle shifting and the control to downshift into needed gear before going WOT and even to force 2nd in the burnout to save the drum...I mean a gazillion reasons with millions of cars beyond turbo 400 gearing is the norm....

AND we want it without having to cut the tunnel out our 67 Camaro to fit an 8L90...there may not be a WAY to do it without destroying the durability of the 4l80e but questing why someone would want it......kinda crazy considering the trans was rendered obsolete 20 years ago because of that it can't do.....

I really appreciate you Jake, used and sent many to you but yes I'd love to have more gears, a steeper first with a gear split perfect to drop rpm less than a 1000 during the entire 1/4 mile run and have double even triple over drives without cutting my car....or needing to drive the engine with a factory PCM....of coarse people want this, why they wouldn't would be a bigger question....hell why doesn't everyone at every weight not run a glide? I mean how many gears does someone really need...hell 1 gear is fine.....Jesus....

ok you cant build one to hold like this can the TCI revision from this year? Cause I'd love it in my car if it really could hold 850hp long term without cutting my trans tunnel out of running an e92 pcm....buy why would someone want it? Why not? Unless it's a radical loadout with loose stall and to much power......

I was just looking for the 2.75 planetary for this new clean sheet build looks like those are gone too...im gonna end up with a rear gear steeper than I want st cruise to get the hit I'd like in the first 300ft.....

That said I personally appreciate the work you have done on the 4l80e over the years....

Anyone know how much it cost a 6l80 to live, if it fits a 67 Camaro without cutting and are there stand alone controllers for it??


Thanks

pjwollman

I have been having a discussion on Yellowbullet https://www.yellowbullet.com/threads...ft-vb.2668506/. About modifying my TCI 6X valve body to a full tip-tronic shift with engine braking in all quote-unquote 6 gears. Jake is supposed to have a 4 speed VB that does electronic shifting and engine braking early next year, but of course, that will eliminate the mid-gear shift splits. I wish Jake would look at doing a modification to the 6X VB for those of us that have the 6X and are looking for the transmission to have engine braking and better shift quality.

pjwollman

Just an update:

According to Jake's Performance: They have a new product announcement that says their engine braking VB has been in the pipeline for some time and due to customer demand, it's nearing completion of the 4L80E Full-Time Engine Braking valve body. This will give engine braking in all gears at all times. This will allow for manual transmission-like performance when using paddle shifters. It will be available with fully accumulated shifts. It is supposed to work from the D-4 position so for me that would work with my Lokar sport mode shifter for electronic bump shifting. So for now I would be converting my TCI 6X back to a standard 4 speed without the gear splits using the overdrive clutch.