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1993 RMW, 1992 OCC
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Discussion Starter · #1 ·
Planning for my RMW winter project is coming along. I've settled on an engine to replace the very tired L05 (no, it's not the 6.5 diesel I was originally planning on, I think that'll end up in my OCC instead). Now I need to decide on a transmission.

I have enough manual-trans cars, I don't need more, and I want the RMW to remain an automatic, so T56 or TKO are out.

It's my fair-weather daily driver, it sees aggressive street driving when the family isn't in there, and very sedate driving when they are. It may also see very occasional autocrossing and drag racing, though street driving is the primary consideration. I don't really care about ultimate ET from split-second-faster shifting and such, I mostly care about the transmission finding the right gear at the right time when I mash the go-pedal at some random time, and the transmission living a long, happy life carting the family around. Highway fuel economy is also a consideration.

So with this in mind, I'm very torn between a PerformaBuilt 4L60E Black or a TCI 6X. The first gear of each is very similar, though the 4L60E has a deeper overdrive that I like. I think PerformaBuilt uses different gear ratios in their Black builds that are more evenly spaced than the OEM ones, though I've found no details on that. The extra 80 pounds or so of the 6X doesn't matter much to me.

The 4L60E would integrate nicely with the MS3Pro engine controller I'm planning on. The 6X would probably require its own EZ-TCU controller. Either one could be setup for the aggressive/sedate driving schemes I'm planning on.

I'd love to hear some feedback from anyone who has experience with these transmissions, especially in regards to street driving.
 

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Slightly off-topic, but if I were going to build another 4L60E, I would definitely use one of the 4L79 kits.

Also, there's a 6L80E in my local yard. Just figured I would mention it.
 
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I mostly care about the transmission finding the right gear at the right time
Regardless of transmission, this is all in the shift schedule. It really requires YOU in the seat observing your speed and knowing what you would have wanted to do at that time, then adjusting it. Takes a number of iterations to get it how you want.
Even my bone stock 95 got a bit of tweaking as i didn't like when it up and down shifted in crawling traffic. Beside the more performance downshift curve i gave it.
 

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So, may I ask, what is the attraction of the MS3pro?
Seems to ,
Needs a separate wideband
Needs a separate controller for either trans
 

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1993 RMW, 1992 OCC
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Discussion Starter · #5 ·
So, may I ask, what is the attraction of the MS3pro?
Seems to ,
Needs a separate wideband
Needs a separate controller for either trans
Direct, plug-n-play support for the engine I'll be running, and I need a TCU controller anyways. I don't have one. The MS3Pro transmission module costs a fair bit less than TCI's EZ-TCU. I'm not aware yet if the MS3Pro transmission module can control a TCI 6X, but it can definitely manage any 4L60E/4L80E. That means less wiring since the module just reads engine parameters from the CAN bus of the MS3Pro.
 

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Discussion Starter · #6 · (Edited)
Regardless of transmission, this is all in the shift schedule. It really requires YOU in the seat observing your speed and knowing what you would have wanted to do at that time, then adjusting it.
Let me rephrase that: I want the ideal gear for the current situation to be available when I mash the go-pedal at some random time. The current gearing of a 700R4 annoys me sometimes. I floor it getting on the interstate, and the best available gear is the super long 2nd because I'm out of range of the super short 1st. The 6X has a gear in between. Same thing between the 4L60E's 2nd and 3rd gears. I don't know if PerformaBuilt's Black transmission resolves this with different gearing.
 

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Let me rephrase that: I want the ideal gear for the current situation to be available when I mash the go-pedal at some random time.
The current gearing of a 700R4 / 4L60E annoys me sometimes.
I floor it getting on the interstate, and the best available gear is the super long 2nd because I'm out of range of the super short 1st.
A 3.42 or 3.73 ring-&-pinion compensates somewhat for this.
The rest is fine-tuning / calibrating the shift points with great care.
For sufficiently different driving purposes, a separate 'Performance' shift table comes in handy, provided it is well-calibrated differently from the 'Normal' shift table.

Only other way I can think of to mitigate your very valid gripe, is to give the engine more RpMs to work with …

That said, especially by modern standards, the 4L60E is a wide-ratio 4 speed transmission (for example, the 6L80E).
All the more reason to fine-tune the shift points as carefully as possible to suit your taste.
 
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Discussion Starter · #8 ·
A 3.42 or 3.73 ring-&-pinion compensates somewhat for this.
The rest is fine-tuning / calibrating the shift points with great care.
For sufficiently different driving purposes, a separate 'Performance' shift table comes in handy, provided it is well-calibrated differently from the 'Normal' shift table.

Only other way I can think of to mitigate your very valid gripe, is to give the engine more RpMs to work with …
I already have a 3.42 posi rear end and a very built 700R4 in the OCC, and while it helps somewhat, it's still not where I'd like it to be. The engine I'll be using does have a pretty wide torque curve, but it's not a high revver by any means and it has an ideal range where the turbo is at its most efficient. This is why I'm considering either more gears or a more optimized spread. There's also the decreased efficiency of the 4L80E (which the 6X is built from) vs the 4L60E to consider, and the shorter overdrive where a 3.42 rear end might not do so well.

Also, there's a 6L80E in my local yard. Just figured I would mention it.
I considered that! :D However upon looking into it, I found that the 6L80E has too wide a ratio for the kind of car I'm putting together. That 1st gear is really meant for hauling or towing a heavy load, it's mostly useless for a hot rod unless you're looking to smoke the tires at every stoplight. It does make a nice close-ratio 5-speed if you eliminate 1st gear, but then I'm installing a heavy 6 speed to use only 5 of its gears, whereas I'd be making use of the 6X's entire range. At that point, I might as well eliminate one more gear and go with a more efficient 4L60E.

I finally found the gear ratios for the PerformaBuilt 4L60E Black, it's 2.84, 1.55, 1.0, 0.70 (vs 3.06, 1.62, 1.0, 0.70 for a regular 4L60E). That's a pretty nice improvement, it keeps 1st and 2nd gears relevant longer and gives a more even spread. So the ratio range is very similar between the 4L60E Black and the 6X. Pairing a 4L60E Black with a 3.42 rear end results in pretty much the same 1st and last gears as a 6X with a 3.23. But the 6X has more gears in between. Whether that's worthwhile considering the 6X's drawbacks (heavier, less efficient, potentially more electronics and wiring required) is what I'd like to figure out. Also, it sure would be nice if I could get feedback from someone who's actually driven a 6X-equipped car on the street.
 

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I already have a 3.42 posi rear end and a very built 700R4 in the OCC, and while it helps somewhat, it's still not where I'd like it to be. The engine I'll be using does have a pretty wide torque curve, but it's not a high revver by any means and it has an ideal range where the turbo is at its most efficient. This is why I'm considering either more gears or a more optimized spread. There's also the decreased efficiency of the 4L80E (which the 6X is built from) vs the 4L60E to consider, and the shorter overdrive where a 3.42 rear end might not do so well.
My guess is that a 700R4's shift points are not as customizable as those of a 4L60E.
… the 6L80E has too wide a ratio for the kind of car I'm putting together. That 1st gear is really meant for hauling or towing a heavy load, it's mostly useless for a hot rod unless you're looking to smoke the tires at every stoplight. It does make a nice close-ratio 5-speed if you eliminate 1st gear, but then I'm installing a heavy 6 speed to use only 5 of its gears, whereas I'd be making use of the 6X's entire range. At that point, I might as well eliminate one more gear and go with a more efficient 4L60E.
The 6L80E … useless for a hot rod?
Pray thee tell, what kind of engine makes a 6L80E's 1st gear useless?

The '09-'14 Cadillac CTS-V had an LSA, a 6L90E, & a 3.23 ring-&-pinion.
I'll admit it's the 1st GM car I ever drove that I thought might have too much rear axle gear; trying to launch it in 1st basically required far better tires than GM gave it - 2.92 might've even been a better choice for many if not most CTS-Vs.
Fact remains that it was far more civilized than I thought, once I re-learned to not use nearly as much foot angle as I was accustomed to with lesser engines.
(The 6L80E's 0.6667 6th gear is no disadvantage either.)
 

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Discussion Starter · #10 ·
Seems like with a 4.03 first gear and a 3000rpm stall speed, I'd be shifting out of 1st in the blink of an eye, even with a 3.23 rear end. I can already light up both tires accidentally with the 700R4's 3.06, a 3.42 rear and a 2800rpm stall torque converter. I'm sure with more advanced engine control electronics and a modern chassis, it would be perfectly fine, but there's a lot of reasons why a 6L80E isn't what I'm leaning towards for this build. That 1st gear is only one of those reasons.
 

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The '09-'14 Cadillac CTS-V had an LSA, a 6L90E, & a 3.23 ring-&-pinion.
I'll admit it's the 1st GM car I ever drove that I thought might have too much rear axle gear; trying to launch it in 1st basically required far better tires than GM gave it
It seems like common sense that when you buy one of the fastest production cars on the road, you may need a bit more rear tire in order to race the thing. It's not like you can just mash the pedal in a Hellcat and expect to hook. After all, these are street cars, not race cars.
 

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Discussion Starter · #13 ·

In for a penny , in for a pound 😏
Bahaha! Yeah, that's extreme even for my tastes. I have a hard enough time wrapping my head around 6 automatic forward speeds 🤣
 

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2 3 4 5 6 7 8 9 are some pretty nice spreads
I drove a '19 Raptor a bunch of miles on a trip.
Certainly wasn't wanting for a ratio.

The 6L80E - 2.93 in my wifes G8 is a great trans although I think this guy was in charge of programing.
4F4B71C300000578-6085779-image-m-15_1534931065987.jpg
 

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GoremanX,
For whatever it's worth, I'm not merely trying to convince YOU to consider or try a 6L90E, but the point is, the more speeds the transmission has, the less necessary a higher-stall torque converter becomes - especially once the transmission is tuned properly for enthusiastic driving instead of aiming for the last tenth of a MpG.

Given a 3.42 or better R&P, a 4L60E vs a 700R4 is like an M193 cartridge vs an M855A1.
I recently showed someone how much more fun his V4P could be with careful 4L60E tuning.

Since I've no clue what engine you're intending, I'll stop beating this dead horse after I say this:
You may very well be selling the 6L80E/6L90E short.
It seems like common sense that when you buy one of the fastest production cars on the road, you may need a bit more rear tire in order to
DAILY DRIVE the thing IN INCLEMENT WEATHER.
(emphasis mine, obviously)
In the CTS-V, in rain or snow, 1st gear was for same-lane U-turns ONLY - never got old.
A second shift table is not needed, but it's still extremely useful and never hurts.
 

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(emphasis mine, obviously)
Who buys a RWD car with a million horsepower to daily drive in inclement weather?

No RWD car past a certain power level is going to hook on the street, even on the most ideal pavement. It's funny to me that the car scene has reached this plateau where the cars are too fast to actually drive. All these guys making 800-1000 whp and all they can do with it is really sweet burnouts.
 

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Who buys a RWD car with a million horsepower to daily drive in inclement weather?

No RWD car past a certain power level is going to hook on the street, even on the most ideal pavement. It's funny to me that the car scene has reached this plateau where the cars are too fast to actually drive. All these guys making 800-1000 whp and all they can do with it is really sweet burnouts.
It's only hard to disagree with the above if one's intellectual potential had been permanently developmentally braked.
In NYC even Sunday night traffic renders anything over 500 rwhp somewhere between stupid and pointless, 'cause the roads suck too.

What I forgot to mention looks something like this:
3.06 * 3.42= 10.4652
4.03 * 2.92 = 11.7676

0.6969 * 3.42 = 2.394
0.6667 & 2.92 = 1.947
If his engine in anyway resembles an LSA, crazy and unsexy as it sounds, less gear, less converter.
 

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It's only hard to disagree with the above if one's intellectual potential had been permanently developmentally braked.
I'm pretty sure you meant to say the opposite of this.
 

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Discussion Starter · #19 · (Edited)
the more speeds the transmission has, the less necessary a higher-stall torque converter becomes - especially once the transmission is tuned properly for enthusiastic driving instead of aiming for the last tenth of a MpG.
Oh I get that. This is why I'm seriously considering a 6 speed. But it gets to a point where the breadth of range in the ratios is needlessly extreme. My foul-weather daily driver (a 2001 Audi A4 wagon that I TDI/6-speed swapped) has such a wide range of ratios, it's annoying at times. The 3.75 1st requires me to shift much too soon when I'm taking off aggressively, and the 0.56 6th puts my RPMs just below the optimal range on the highway to the point where I can't cruise at anything less than 75mph without lugging the engine. I don't need or want that kind of range. I'd be much happier with a range of 3.5 to 0.63, instead.

Since I've no clue what engine you're intending, I'll stop beating this dead horse after I say this:
You may very well be selling the 6L80E/6L90E short.(emphasis mine, obviously)
It's not a secret by any means, I just forget that I haven't shouted about it on every forum 🤣 This is the engine I'm putting in the Roadmaster:


It's from an '87 Grand National, but it's been living in that OCC for the last 18 years. Still runs like a champ with the original long block that's never been opened, though I'll likely replace the rotating assembly and heads this winter.
 
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Discussion Starter · #20 ·
And that's another reason I'm not considering a 6L90E. It requires a fairly expensive GM engine controller that's intended for LSx and new LTx motors and won't work with this engine at all. I'm going with an MS3Pro ECU because there's one available that's a plug-in replacement for this engine with ready-made maps and everything. I mean, there's some (precious few) 3rd-party standalone TCUs available for the 6L90E, but they're even more expensive, and at that point I'm going out of my way to integrate a transmission with a ratio range I don't really want in the first place. Most of my hesitation on the 6X comes from the potential requirement to use TCI's EZ-TCU module.
 
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