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I had more than 100 tweaked calibrations by the time I was really happy with my 4L60E.
Pretty much same here.
4L60E & gottdamnt 2.56 … most of the time & mental energy on all the 2Up3 & 3Dn2 shifts, in the beginning.
Once all the 2Up3s & 3Dn2s finally got worked out just right for sure, started allowing 4th gear use again.

4L60E & 3.42 was 10x more satisfying to tune, and 50x more satisfying once finally calibrated.

What other gear spreads are available for a re-geared 4L60E?
 

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Discussion Starter · #42 ·
What other gear spreads are available for a re-geared 4L60E?
I don't know of any beyond what PerformaBuilt offers, and I'm not even sure about that. The numbers I'm using are from a 5 year-old Super Chevy article, which is one of the first search results when you type "4L60E gear ratios". These are all the gear ratios I've been able to find for 4L60E and 4L80E transmissions:

OEM 4L60E - 3.06/1.63/1.00/0.70
PB 4L60E - 2.84/1.55/1.00/0.70 (supposed)
OEM 4L80E - 2.48/1.48/1.00/0.75
TCI 4L80E(1) - 2.75/1.57/1.00/0.75
TCI 4L80E(2) - 2.97/1.57/1.00/0.75
TCI 6X - 2.97/2.23/1.57/1.18/1.00/0.75

What's interesting is that I think it would be possible to customize the valve body to add a 2.14 gear between 1st and 2nd on a 4L60E, thereby turning it into a 5 speed with a decent spread. So it could go 3.06/2.14/1.63/1.00/0.70. That would completely resolve the 1-2 spread issue, maintain a really good overall spread (better than 4L80E), and still keep the ratios far enough apart that a turbo engine stays in any gear long enough to reach its optimal range. I'm surprised this hasn't been done already, though it would likely require some serious added holding power in the 4th gear clutch pack. I like that spread a lot more than the 6X's (1.18 to 1.00? Really?!?)
 

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Me thinks it be more than a valve body to get 5 gears...
Anyways, interesting the PB 4L60 has the same ratios as the 4R70W...
 

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Discussion Starter · #44 · (Edited)
Me thinks it be more than a valve body to get 5 gears...
Nah, its pretty straightforward. That's exactly how TCI does it for the 6X. If you take the second TCI 4L80E gearset that I listed above, and multiply the 1st gear by 0.75, you get 2.23. And if you multiply the second gear by 0.75, you get 1.18. They're basically just applying the OD clutch pack to the 1st and 2nd gears to make 2 intermediate gears, for a total of 6. All that's needed for that is a modified valve body and maybe one more solenoid. Also, to make sure the OD clutch pack can handle the torque multiplication of 2nd and 4th gears, they add a bunch more holding ability in there. This is no different than the way GM added a 6th gear to the Allison 1000 5-speed back in the mid-2000's. Anyone with a 5-speed could gain the 6th speed by just adding a tube to re-route fluid within the valve body and getting the TCM reprogrammed. There were all kinds of kits available to do it. I did it with my old '93 Suburban C2500 that ran a 2006 Cummins ISB-300 with an Allison 1000 5-speed.

edit: to clarify, the Allison 1000 thing is slightly different because it has 3 planetaries and the valve body and TCM modifications only enabled a different combination of them, whereas in the 4L60E's case we're talking about enabling the OD clutch pack in combination with an existing gear, but the basic premise remains the same, it's only a valve body modification and solenoid arrangement. My guess for why it's not been done yet with the 4L60E is that the OD clutch pack doesn't have enough capacity to provide enough holding force, whereas the 4L80E does.
 

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GormanX ,
I will stand corrected if you can prove you can get 6 gears, reliable or not out of the existing hard parts in a 4L60E.

What I see, the 4L80 is the 3 speed TH400 with an internal overdrive hung on it.
TCI and others have found the different combinations to utilize the THREE planetaries and clutch combinations to get the 6 gears.
Like the TH400 , the stock 4L80E making 4 gears forward, is super simplistic. just keep turning on elements for each gear , never turning any off.
The beauty , no overlapping applys, releases.

Now the 4L60E , it is a marvel of turn this on , turn this off, turn this back on, just for normal 4 gears.
It only has two planetaries .
Please Prove me wrong, I don't see enough parts in a 4L60E to make 6 forward gears .
 

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NO ENGINE BRAKING !!!!!
Oh here's a great thread for someone looking at the 6X
 

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Discussion Starter · #47 ·
You may be right that the 4L60E can't easily have an added gear through valve body modifications, I'm not familiar enough enough with how the OD is laid out in there to know for sure. But TCI's 6X is absolutely accomplished by engaging/disengaging the OD gear in combination with a 4L80E's usual 1st and 2nd gear ratios. This is one of the reasons why drag racers dislike it, the shifts from 1 through 5 all require engaging and disengaging OD, and some shifts (2-3 and 4-5) require doing so at the same time as switching planetary engagement, which results in much slower shifts than a regular 4L80E. And this is due to exactly what you describe, the OD is just tacked onto the end of what's mainly a TH400. So the OD can be applied to any of the regular speeds.
 

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Discussion Starter · #48 ·
NO ENGINE BRAKING !!!!!
Oh here's a great thread for someone looking at the 6X
Actually that's pretty old and the software has resolved that issue since then. You can engage lockup in any gear at any time, automatically or manually.
 

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seems to be still going on as of 2021

I see this as not torque convertor lock up related, the is the trans overrunning the input .

4l60E first gear = forward clutch

if you just add 2-4 band that is 2nd gear
if you just add 3-4 clutch that is 3rd gear
if you add both that is 4th gear
 

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Discussion Starter · #50 ·
seems to be still going on as of 2021
Ugh, all the more reason to avoid the 6X, then.

If I want more gears, I can always just fake them with TCC lockup in every gear... then I can turn a 4L60E into an 8-speed 🤣
 

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If I want more gears, I can always just fake them with TCC lockup in every gear ...
then I can turn a 4L60E into an 8-speed 🤣
If anyone has managed to lock the TCC in 1st without a TCC manual override switch, it's news.
Most tuners can figure out TCC lockup in 2nd, 3rd, & 4th. Feels pretty weird locked in 2nd though.
 

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Discussion Starter · #52 ·
If anyone has managed to lock the TCC in 1st without a TCC manual override switch, it's news.
Most tuners can figure out TCC lockup in 2nd, 3rd, & 4th. Feels pretty weird locked in 2nd though.
Depends on the controller being used, I guess...
 

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Discussion Starter · #53 ·
For a while, the 700R4 in my Roadmaster was mysteriously turning on TCC lockup in 2nd and 3rd gears (which I thought was impossible). You're right, it did feel weird. Especially with cruise control on. The whole car would shudder oddly as the throttle was modulated to maintain speed. This lasted for a couple days, and then it went back to normal behavior (lockup only in OD). Never figured out what the cause of that weirdness was
 

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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.
Um, just to clarify: the CTS-V is a wonderful daily driver, and that includes daily winter driving in the Northeast. Proper winter tires and judicious application of throttle are all that is necessary to make it work (y)
 

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Um, just to clarify: the CTS-V is a wonderful daily driver, and that includes daily winter driving in the Northeast. Proper winter tires and judicious application of throttle are all that is necessary to make it work (y)
I'm glad you find it to be wonderful, but that's irrelevant. You can't hook. Period.

Caddylack said:
Who buys a RWD car with a million horsepower to daily drive in inclement weather?
This was a rhetorical question.
 

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Depends on the controller being used, I guess …
Managed to recall, someone named Doug Wood figured out how to manually lock or unlock the TCC at will, while also allowing the PCM to lock / unlock the TCC normally without throwing any codes.
He didn't like locking it in 2nd or 1st either.
For a while, the 700R4 in my Roadmaster was mysteriously turning on TCC lockup in 2nd and 3rd gears (which I thought was impossible). You're right, it did feel weird. Especially with cruise control on.
The whole car would shudder oddly as the throttle was modulated to maintain speed.
This lasted for a couple days, and then it went back to normal behavior (lockup only in OD).
Never figured out what the cause of that weirdness was.
Today, many transmissions (more speeds, much deeper gearings) lock the TCC in 2nd or even 1st.
What's so different about the 4L60E that locking the TCC in 2nd (or even 1st?) makes for such unpleasant shudders?

I find it difficult - not impossible - to imagine when locking the TCC in 2nd or 1st would be beneficial with minor acceptable drawbacks.
 

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Discussion Starter · #57 ·
Most modern transmissions partially lock the TCC in 1st or 2nd to improve drivetrain efficiency. They have a PWM solenoid that varies duty cycle to allow that. There's still some slippage in most cases, and the TCC lockup releases as soon as you let go of the throttle. My transmission wasn't doing that for those couple days it was acting up. It wasn't releasing unless I pressed on the brake.

The 4L60E also has a PWM solenoid for the TCC lockup, but its purpose is to generate a smooth, gradual lockup engagement. It's called the "lockup feel", and its function is built into the transmission, it's not usable by the controller. I don't think it can be used to properly maintain a partial lockup. Also, many performance transmission builders disable that feature because it leads to accelerated TCC wear.

Having said that, for a WOT acceleration run, it's probably entirely possible to simulate more speeds with TCC lockup. But I don't know if it's worthwhile performance-wise.
 

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Most modern transmissions partially lock the TCC in 1st or 2nd to improve drivetrain efficiency.
They have a PWM solenoid that varies duty cycle to allow that.
There's still some slippage in most cases, and the TCC lockup releases as soon as you let go of the throttle.
Seems it's cheaper or easier to (partially) lock the TCC than to make a very tight fluid coupling.
My transmission (700R4?) wasn't doing that for those couple days it was acting up.
It wasn't releasing (the TCC) unless I pressed on the brake.
Don't remember if Doug Wood integrated brake control into his manual TCC lockup controller?
There are certain instances where it's ok or even desired to keep the TCC locked while the TPS%=0, but I'm almost sure they would not apply to the 4L60E while in 2nd or 1st.
One of the few things I never tried in any of my tunes was using PWM TCC mgmt values to lock the TCC in 2nd.
I'm not sure it would be worth the effort …
The 4L60E also has a PWM solenoid for the TCC lockup, but its purpose is to generate a smooth, gradual lockup engagement.
It's called the "lockup feel", and its function is built into the transmission, it's not usable by the controller.
I don't think it can be used to properly maintain a partial lockup.
Also, many performance transmission builders disable that feature because it leads to accelerated TCC wear.
Since 1995, the PWM solenoid is in fact controlled by GM pcms.
Luckily it can also be disabled in the pcm by simply using pre-PWM TCC mgmt values.
Having said that, for a WOT acceleration run, it's probably entirely possible to simulate more speeds with TCC lockup.
But I don't know if it's worthwhile performance-wise.
I very much doubt it would be worth simulating more speeds with TCC lockup during WOT runs.
I do know that TCC locking during WOT requires an uncommon TCC clutch construction spec'd and built specifically to withstand it.
 

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Discussion Starter · #59 ·
Yeah I was planning on a 10.5" TCC with triple disc clutch to maximize lockup hold. Might be fun to play with some WOT shifts at full lockup, just to see what its like until I get sick of it 😂
 

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Yeah I was planning on a 10.5" TCC with triple disc clutch to maximize lockup hold. Might be fun to play with some WOT shifts at full lockup, just to see what its like until I get sick of it 😂
I can't imagine WOT shifts with a locked TC is very nice to the trans lol
 
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