[max 93]

I have a 2004r that has been converted for use with a non lockup converter. Can I use a lockup converter with it ?

[Steve C.]

See jakeshoe's post here:
http://www.chevelles.com/forums/showthread.php?t=339828

I first had a lock-up converter in my 200-4r but later had the transmission changed to run a non-lock up Continental converter. Under a steady state cruse speed on the open highway the converter has about a 200 rpm slippage, very acceptable in my opinion. With my 27.7" diameter rear tire and 3.73 gears it is about 2300 rpm at 70 mph.


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[max 93]

I guess I should clarify a little. When I conveted to non lockup, I installed a used converter. I am suspecting that the converter is either no good or just not what it was supposed to be. I do have a differant lockup converter that I may want to install for testing purposes. I am not looking to use the lockup feature.

[Radman]

I have a lock-up converter with my 700R4. The lock-up is on a vacuum switch. It will not lock until I have 14 inches of vacuum and am in 4th gear. I also have a switch that I can keep the lock-up from locking. With the converter locked the RPM's drop another 200 RPM. Why not have both worlds working for you?

[Cliff R]

Nothing at all wrong with going non-LU if you have an efficient converter. It's actually nice to have just a little bit of torque multiplication when you ease into the throttle to climb a steep grade, make a gently pass of another vehicle, or drive pretty slow in 4th gear.

I owned and drove a 67 Impala SS for many years with a 4L60. When first installed it had a LU converter, and I absolutely HATED it. It was set up on a 4th gear pressure switch and vacuum switch to only allow LU at part throttle cruising just like the factory LU converters.

It was OK on steady cruising on the highway at higher speeds, but "lugged" the engine and quickly came out of LU in the scenarios described above.

I blew up that converter and converted the trans to non-LU. Bought a pretty expensive non-LU converter from Precision Industries and absolutely LOVED it. It was as tight as any stock converter for "normal" driving, but flashed much higher when hit with full power. For "normal" driving it locked right up and at most rpm's would increase about 150 when you got heavy into the throttle climbing a steep grade or accelerating briskly in traffic. The engine no longer "lugged" or needed a lower gear, etc.

Both set-ups yielded mid-20's for fuel economy on the highway, averaged about 18mpg's everyplace else.

To modify a 200-4R for non-LU the check ball and capsule in the input shaft is removed, and a non-LU valve installed in the pump. It will no longer work correctly for a LU converter and those parts need to be re-installed. I'm not even sure if you can test the non-LU converter effectively even if you don't plan on using the TCC?......Cliff

[Formulajones]

Like Cliff mentioned, the lockup converter won't work unless those pieces are reinstalled.

My opinion, I like to have my cake and eat it too, and having a nice working stall converter with the lockup feature on top of that is the best of both worlds.

Unfortunately the 200's and 700's fight with this scenario because it's still controlled by a TV cable and a vacuum switch. Just not alot of wiggle room there and they can be a pain in the rump when you want to lug the engine around in 4th gear, especially an engine that has a large cam with alot of overlap. The vacuum switches do offer some adjustment here, there is a set screw in them. Helps some but it's not a cure all since the trans still relies on the TV cable as well. They just aren't friendly in this situation.

Best scenario is to run an electronically controlled trans (4L80E or 4L60E). These transmissions work beautifully with lockup stall converters. With infinite control over all parameters from throttle position, MPH lockup and unlock, and rpm shift points. You can fine tune the trans exactly to how the engine likes to operate with light throttle tip in converter release or late lockup depending on what the engine or the operator likes, and much more. All at the push of a button.

It's the only way I'll run an overdrive auto nowadays, and mainly what I retro swap here for others. They just have too many advantages in my opinion. Either that or just go manual overdrive.

[Cliff R]

The TCC works a LOT better when the vacuum switch is hooked to a correctly located ported vacuum source. The voltage is ran on to the transmission to a normally "open" 4th gear pressure switch.

This will only allow LU at light throttle cruising once the transmission has reach 4th gear. Any heavy/full throttle instantly unlocks the TCC, and it will unlock coasting or at idle, just like the factory did.

Direct wiring or using a toggle switch works poorly, for best TCC operation it needs to unlock in a variety of driving conditions, and really doesn't need to LU until the transmission reaches 4th gear (overdrive).......IMHO......Cliff

[frankyboy455]

not to hijack this thread but where can one get such a vacuum switch ?

[Cliff R]

TCI (and others) make a kit that comes with the 4th gear pressure switch and vacuum switch. Some will also include a brake pedal switch, and toggle switch to take the TCC out of the deal completely if desired.

http://www.jegs.com/i/TCI/890/376600...oductId=748599

As long as the 4th gear pressure switch is functioning correctly, all that is needed is a vacuum switch and a normally open 4th gear pressure switch to make it happen. The brake pedal switch would be a back-up so the TCC didn't kill the engine if the 4th gear switch failed. The toggle would be a second back-up, if needed.

I'm not a big fan of LU until the vehicle reaches higher speeds and very light load. Even my 2000 Tahoe performs a LOT better everyplace when the TCC is still not working due to the temperature on the transmission fluid being too cold. Being a heavy vehicle with poor overall gearing it absolutely LOVES the additional torque multiplication in all gears for "normal" driving on these old Country roads that I live on. The only time it really enjoys the TCC is over 60mph on the highway. For all other driving it's more responsive and just kicks out the TCC anyhow anytime you start up a grade or accelerate briskly at lower vehicle speeds.

One of the very best things I did for the Tahoe was to install a Super Chips that raises LU to 59mph or higher. The factory would have it lock in as early as 37mph, and the vehicle absolutely HATED that deal......FWIW......Cliff

[Overkillphil]

I prefer and use the adjustable speed sensor control and wire it through a later model brake pedal switch. Lockup can be set via a small rotary dial from 20-90 mph.

If the car is 1/4 mile raced, a simple override switch can be installed ahead so there is no lockup at the track (>90). Adding the adjustable vacuum switch Cliff speaks of would make this an even better setup.

[Formulajones]

What Cliff explained towards the end of his last post is exactly why the lock up converters get a bad wrap. They almost always need tweaked from the original settings for any retrofit application or an engine that's been modified.
He's right on the button, the factory calibrations on everything I've worked on, even electronically tuned, show most lockup occurs below 40 mph if the conditions are met (throttle position sensor, speed)
Some of these issues are also related to how the vehicle is geared and tire height. I really don't care for automatic overdrives that cruise along and lug the engine below 2,000 rpm on the highway. Any grades or moderate throttle to accelerate makes for a very lazy running car that hunts for gears if you are lugging the engine at 16-1700 rpms. I much rather prefer to gear the car to cruise in the 2,000-2,400 rpm in overdrive at 65-75 mph speeds, and have the converter lock much higher than the factory settings. Much more pleasurable to drive and maintains speeds up hill without much throttle input.

[Overkillphil]

Regarding Cliff's Tahoe, same issue here with the factory calibration in our Durango 5.9 R/T. The lockup occurs right before the normal shift to OD and it loads the engine all at once, causing it to lock-shift to OD(4th)-unlock-stabilize and lock again. Very irritating. I end up leaving the OD switched off unless getting on a highway for a bit. I don't know where these powertrain engineers test these vehicles that they don't notice this crap.

[Formulajones]

Originally Posted by Overkillphil

Regarding Cliff's Tahoe, same issue here with the factory calibration in our Durango 5.9 R/T. The lockup occurs right before the normal shift to OD and it loads the engine all at once, causing it to lock-shift to OD(4th)-unlock-stabilize and lock again. Very irritating. I end up leaving the OD switched off unless getting on a highway for a bit. I don't know where these powertrain engineers test these vehicles that they don't notice this crap.

Those types of calibrations are there to meet the tight fuel mileage requirements, coupled with the mild gear and tire height that the OEM runs it's not always the best scenario for all driving conditions.

[Overkillphil]

Agreed, however it cannot be good for converter clutch longevity not to mention it's very annoying. Powertrain Engineers should be able to optimize calibrations to avoid this nonsense as not all makes and models have these problems.

[Formulajones]

I agree that it can't be all that great for the clutch life to cycle in and out all the time. I believe their thinking is that the car just has to make it out of warranty

You're right, it's not apparent in all makes and models. It has alot to do with gearing, the weight of the vehicle, aerodynamics, and whether the engine makes any usable torque down low in those barely off idle conditions.

So in the SUV's that are heavy, or sit up high catching alot of wind, and generally don't have much more than a 3.42 gear (or less) and have 350 cubes or less, you'll find they tend to hunt for gears more often than not.

[HWYSTR455]

Lockup delay boxes cure the hunting problem. So it's best to use the vacuum switch, speed select lockup box, and the lockup delay all together.

E-trans models cured the issue with TPS and the combined sensors/data points mentioned above. You can overcome unpredictable vacuum conditions with the TPS, as well as unlock at zero throttle. You get less of a lurch too, since you can lockup at say 1 or 2 % TPS.

E-trans also allows you to select additional gears for lockup, say like 3rd & 4th, not just 4th. (useful for parkway cruising at say 45-50, where there are lights you have to stop for, as an example)

Nice thing about lockup is that you can have a 'looser' or higher stall converter than you would normally select for a dual-purpose car, and overcome it with lockup control.

Even some newer trucks still have a 'towing' mode which keeps the converter locked up.

I realize there's a debate on the lockup/no lockup topic, but having tried both in a number of scenarios, hands down, I would choose lockup any day. Cost is a factor, and good lockup converters are far from inexpensive, which I think causes many to choose differently, especially at higher power levels.

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[tpssonic]

I have a 2004R with the lock-up using the B & M adjustable speed sensor control and it is great. I did not wire it through a later model brake pedal switch, however. Works better than I had expected. Drives like my mini-van, but with waaay more power on tap.

[Goatracer1]

I've used a 200-4R for 14 years in my blown 1967 GTO. I only have a manual switch with a brake cutout. I don't mind locking/unlocking myself and being able to lock it in 3rd gear is handy sometimes. I use a Precision 5 disc converter and it drops the rpm about 300-400 at highway speeds.

[ponjohn]

I think the method in which the converter is controlled is the real issue.

A 4l80e can have many more parameters in which the decision to lock / unlock is made.
If you are just relying on vacuum then there are going to be circumstances that are in between ideal.

My next drivetrain will have a 4l80e with a lock up converter. I've already spoken to a few converter companies and they say that having a stall in first and lockup from 2-4 is being done all the time in retrofit installs.

[Cliff R]

The efficiency of the converter for "normal" driving is the other big player here.

If you are building a "driver" and using an efficient converter, and optimal gearing, you woln't miss the lock-up feature in the least. Don't believe all the nonsense about overheating the trans either. Factory vehicles with 2.56 gearing and standard type converters in pretty heavy vehicles lived for decades with zero issues. Why would having more optimal gearing with overdrive be any different? The overheating difference would be trying to employ a pretty "loose" converter into the scenario and not using the TCC.

Any sort of "stall" converter, especially cheaper units built on smaller cores will show some slippage unless it has a TCC, so the operator will see 200-300rpm's difference when the TCC is applied at light throttle cruising at highway speeds. A well built efficient converter will at most see 150rpm's, some little if any noticeable difference at all once highway speeds are reached, so the TCC doesn't bring much to the table with a better converter.

For most driving situations, I do NOT want the TCC applied, in any gear. I've owned a number of vehicles and prefer to have a little torque multiplication until I get out on the highway in overdrive and very light load, then having the TCC applied is OK. It still needs to unlock when you start climbing a steep grade, or accelerate briskly to make a pass without downshifting, etc, or it will lug the engine some.

For my personal vehicle I have a Nissan Altima with CVT. Now there is the "best of both" Worlds when it comes to this topic. Locks right up at light load, and puts the engine at optimal rpm's based on engine load and desired vehicle speed. Feels sort of like you are slipping the clutch to climb a steep grade or accelerate quickly to make a pass, etc, then the engine drops right back down to the lowest possible rpm at very light load. No wonder Honda, Subaru and I suppose everyone else are jumping onto that deal these days.

Anyhow, over the years I've owned driven a number of trucks with OD and a TCC, and have hated most of them since the factory locks up the TCC too early and often in lower gears. The constant locking in and out of the TCC in traffic when you are on and off the gas and changing speeds constantly sucks. I'd rather wire the TCC thru a ported vacuum switch and ground it on a 4th gear pressure switch. Incorporating a delay, or MPH switch to keep in out of LU below about 50mph or so would be another EXCELLENT feature.....IMHO.

Direct wiring and toggle switches are common for this topic, don't like that deal at all, too many distractions already in todays driving scenarios to have something else to fiddle with.......Cliff