Automatic Transmissions

[Dynoroom]

No converter no problem!
Many before you have done it...

[ggl205]

Haven?t done it yet and don?t know how but plan to learn. Looks like the coupler I will need does not exist. One will have to be made.

John

[ggl205]

So, I am looking seriously at direct drive to an automatic transmission. All seems quite good until I read of catastrophic failures, mostly due to shifting into neutral at the wrong time. Anyone out there have experience with this? Solutions for it?

John

[1leg]

I have always been told to never shift a GM trans into Neutral when at speed above 10 MPH. I'm Assuming that it is the same with other brands. In drag racing you can build a TH400 with what they call a "clean Neutral" so you can after a run but it require some modification to the valve body. Not exactly sure how this is done.

[desotoman]

So, I am looking seriously at direct drive to an automatic transmission. All seems quite good until I read of catastrophic failures, mostly due to shifting into neutral at the wrong time. Anyone out there have experience with this? Solutions for it?

John

John,

I put a turbo 400 in my boat back in 1978 behind a Supercharged 454 no torque converter. This was before I knew John Kilgore, so I went to Marv Ripes who owned A1 Transmissions in Van Nuys, Ca.  At the time Art Carr made a input shaft that eliminated the torque convertor and drove through a plate as I recall that was used with a velvet drive that had springs in it for shock and bolted up to a standard flywheel. I was very concerned at the time about shifting into neutral with the standard pattern since I was using a simple lever to shift the transmission. Marv told me they made a reverse pattern valve body that would solve my concern about shifting into neutral so I had him put one in. PRN123. I still have the boat and in the 43 years of running it have never ever had a problem with the transmission.

Forward to 2005, the Street Roadster I ran at El Mirage had a Kilgore turbo 350 in it and ran without a torque converter. It had an adaptor that you bolted to an automatic flex plate that drove the pump and transmission. I never drove the car as I was too big to fit in it, but as I recall the shifter had a lever you had to move up to get it into neutral and that lever prevented you from shifting into neutral. The transmission would free wheel if the motor RPM was lower than the speed needed to move the roadster for 1st gear. My push truck is a 97 Dodge diesel 5 speed stick, I did not want to shift the truck while push the roadster so I would push off in 2nd gear and when the truck hit its max RPM of 2900 I would honk the horn and the driver would drop the trans into 1st gear bring the revs up to engage the trans and drive off the truck. Very simple. Never had a problem with the Kilgore turbo 350 trans either and still have it, in fact I took it back to John years ago and had him take it apart and look at it and it was in perfect shape. If you want a turbo 400 I would call John Kilgore, JMO.

Tom G.

[ggl205]

Tom, 1leg:

This is the kind of thing I am after, real life experience. I heard of the reverse pattern but a separate lever that essentially removes possibility of shifting into neutral, is a great way to go.

the driver would drop the trans into 1st gear bring the revs up to engage the trans and drive off the truck.

Tom, how does that work with no converter?

Thank you both for the input and recommendations.

John

[desotoman]

the driver would drop the trans into 1st gear bring the revs up to engage the trans and drive off the truck.

Tom, how does that work with no converter?

John

John,

Disclaimer, I am not a transmission guy, I have them built for me. 

Some people tried running Powerglides in Circle track cars without convertors and they would put a valve on the pressure side and engage it slowly in low gear to get the car rolling.

The Kilgore turbo 350 in the roadster free wheeled when you let off the gas at least in 1st gear. If I had driven the car I could tell you if it was the same in 2nd and high, but I never did. So we would start the car when the starter came up to check the driver and let it idle. The cam in that motor would idle pretty low as I recall around 750 to 800 RPM. When the starter gave us the OK to go the driver would leave the car idling while I pushed the roadster up to max rpm of the push truck in second gear, which was around 20 mph and when I hit the horn they would put the transmission into first gear, bring the motor up in rpm and as soon as motor rpm was what it should be for the speed the roadster was going in first gear it would engage the transmission and leave the truck. The driver could feel this and give it throttle accordingly so they would not spin the tires in low gear. 4 or 5 different people drove the car and never had any problems.

I hope that is clearer than mud.

Tom G.

[ggl205]

Tom, your start procedure explanation clarified things for me. Thank you for that information. It is very clear now what I need for my car.

John

[kiwi belly tank]

I have a converter-less 400 on the KB in my liner but I haven't run that yet. I initially intend to push off then pull low gear with the O/D units in direct, I think the calculated speed was 34 mph @ 1500 with a 30" tire. Once I get serious the intent is to lose the push truck & use the O/D direct clutches to drive away from the start line. The oval track guys run Powerglides, 350's, 400's & C4's without converters & just tap into the front clutch pressure & bypass it with a ball valve then slow close it to bring in the clutch. That's the same principal I'm using with 400psi of co2 for my setup.
The lack of flywheel or converter weight in oval track is desirable for faster engine acceleration & deacceleration but could be a problem on the salt especially in deacceleration with the possibility of losing traction creating a spin. Even though mine is 4WD with two transfer cases & two O/D's, I've used a steel clutch-type flywheel with the TCI direct coupler.
  Sid.

[ggl205]

could be a problem on the salt especially in deacceleration with the possibility of losing traction creating a spin.

Sid, wouldn?t this be the same problem for a manual transmission on deceleration? At that point, both are direct drive. Other than occasional throttle pedaling, you are hard on the accelerator until the chute is pulled.

TCI makes a direct drive coupler welded to half of a converter. It takes a special front pump, they say. I would have to modify my flex plate to accommodate this arraignment but should be pretty straightforward. I do like the direct drive coupler attached to a flywheel idea, however. May have to give that some thought.

John

[Stan Back]

I'm trying to figure out how all these variables are superior to a 4-speed with a clutch -- at least in a car configured with an engine in front, the driver in the middle and the rear end in (wait) the rear end.

[ggl205]

Stan, I have a car with engine behind the driver. Clutch, hydraulics and linkages have always been an issue for me. Additionally, if I can eventually eliminate a push car off the line, that would be a big plus too. It may sound like there are many variables to overcome with an automatic but once sorted out, should prove an advantage, I hope.

John

[desotoman]

John,

I don't think Art Carr makes the adapter any more that I run in the boat. But I found some pictures of what it kind of looks like. One picture is the Velvet drive flywheel flex plate that takes up some shock with the springs. The other picture is of a kit currently made but Carr made a shaft very similar to the one in the picture except it had a nub on the end to fit into the pilot bearing of the flywheel and no cir clip on the shaft.

Also I was just reading up on Circle track Converters and maybe you don't need to eliminate the converter as technology has changed and they may be able to give you a low stall converter that would allow you to drive the car off the line yet not slip on the top end of the run keeping the heat down in the transmission. It would be worth a phone call to some converter manufacturers. Just a thought.

Tom G.

[kiwi belly tank]

John, yes the same situation could be the same if you had a manual trans "without" a flywheel. Using a manual flywheel with a direct drive is easy. I just turned up a centering spud that fits in the back of the crank & the front of the TCI hub to center everything then used 3/8" longer flywheel bolts. My engine protector plate/engine mount plate is 1/4" thick & that gives the shaft .040" end float.

Stan, as John said, we are talking rear engine applications. Remember Betsy was a manual trans & at that speed with a limited distance, how far did Al travel while shifting even after I got it working right, it swallowed up real estate!

Tom, There is a company doing a 400 conversion with a lockup converter but that stuff is never cheap. GM made a limited production of 400's with lockup but they're as rare as rocking horse crap. The 400 with a short housing is 27" long & a 4L80 4WD trans with a 400 short housing on the back is only 2" longer at 29".

The reasons I didn't use a 4L80 in the liner is that extra 2" was real important but I couldn't use the O/D & have the front drive shafts & transfer cases spinning at 10.000rpm.
  Sid.

[SPARKY]

John,  I have run a PG/GV as a 3 spd, T400/GV as a 4 speed a, and a Liberty 5 speed/GV at EL M and B'ville,  all of them in front of a GV overdrive.  I run the GV for gearing,  because it gives me a slight slipper clutch on up shifts and the GV can be set up to free wheel. 

Until my son bought the Liberty I was planning on a T400 with Kilgore 1.91 first gear and some where around a 1.30 ---GV brings the ability to have it set up where it will free wheel ---at the end of a run or if you blow one up it JUST ROLLS OUT no lock up

 what  I loved about the autos i ran circle track couplers and no torque converters---I NEVER HAD TO LIFT pushed off and jerked into gear floored it beefed up internals stock valve bodies I DIDNT want violent shifts..