automatic...

[jyrki sulka]

If my memory serves me well, between -64/-66 they used automatic once (in Le Mans?) in mk2.

After those words I`m brave enough to ask:
1) what type was that transaxle?
2) is there nowdays any -automatic transaxle- what you can use with higher outputleves; like 500+?

Yes, I know, automatic in 40 is almost unforgiveable, but I have my reasons to ask...

 

[Jim S.]

This subject was discussed somewhat indepth about 6 to 8 months ago if I remember correctly.

The trans that seemed like it might possible work was a Dodge Intrepid
It is mounted North and South instead of transverse. I believe you could build one up to withstand the abuse. The other would be an automatic out of an Audi 5000 FWD, but I don't believe this would take near the abuse that the Dodge trans would.

One of the problems is the trans will sit so low you will probbaly end up with the engine higher than you'd like. That's why alot of guys prefer the porsches turned upside down. It moves the bulk of the trans up in the air quite a bit and you can then set the engine much lower in the chassis.


Good luck

 

[jyrki sulka]

Thanks Jim

I`ll investigate that Dodge trans. if it is somehow possible.
Yep, the output of shafts are usually too low when you found something intresting.
Let`s search more too; Olds Toronado, Cadillac big FWD -models, at least they have north-south engines, but rest?

 

[domtoni]

Guys,
Just a thought. Back in the 1960s, GM built the Olds Tornado with a North South front engine. I gotta bet that some of these transmissions still exist, maybe with two speeds, but with plenty of torque, could be great !!!

Might be ideal for a Mark IV !!!

Best
Dom

 

[Howard Jones]

Delorian R21 based automatic.

 

[Steve26]

I put a Nissan Maxima V6 in an Audi 5000 several years ago, it worked and took a real pounding. You could also try the tranny out of an Audi Turbo Deisel and get better gearing. I think the auto trans was used in a MKII at Daytona in 1966 but didn't fare to well.

Steve

 

[Pete T]

The Intrepid trans is a 42LE. They turbocharge these cars but I'm not sure you can put 500HP of v8 through them. Chrysler has a rating system for their transmissions. 42LE breaks down as: 4= 4 speed; 2= torque rating (they go from 1 low to 8 high); L=longitudal; E=electronic controlled. These transaxles use a TCM for determining the shift points' lock-up (converter) as well as conditions such as pressures, rotational speeds, etc. It connects to the ECM for OBD II dianostics. I don't know that this transaxle would be suitable for this kind of application.

The Toronado/Eldorado transaxle is a TH425 (3 spd based on the TH400); the TH325 (3 spd based on the TH350) and the TH325-4L (also based on the TH350. The TH425 is the strongest of them. These can be built to handle anything that a TH400 can. They were used with the Caddilac 500 v8 and Toronado 425 & 455 v8's. The TH325 & 325-4L can be built to handle the same as a TH350. All are available but are not very common anymore. If I were building something with a small block I would choose the TH325-4L because it has 4 speeds. For a big block I would definately use a TH425.

The TH425 came with R & P's between 3.22 & 2:73. The TH425 can also be modifies to use what was called "switch pitch" which was a dual stall speed torque converter. There are places that still build these. I had a friend that had his TH400 modified this way and had 3500 rpm stall and 2200 rpm stall. (he used the car for bracket racing) It probably necessary for a GT-40.


Pete

 

[Eric A.]

The problem with the Toronado/Eldorado transaxle is that they position the engine too far back and too high. There is actually more weight behind the axle than in front of it. There have been some builders who have turned the unit around and moved the differential to the end of the engine and flipped it over. Still a very heavy unit altogether.

 

[Pete T]

Here is a discription of the Chrysler 42LE transaxle:

The Chrysler 42LE automatic transmission (transaxle)

They are good transaxles but I think the TCM would not be easy to integrate. There is a company that clames that they can build a 41TE (FWD 4 spd auto) to take 500 HP. I know that the diff on the 41TE is a limiting factor. The 42TE has a larger one but I have never seen one so I can't say if it is much larger.


Pete

 

[BenL]

The TH425 came with R & P's between 3.22 & 2:73. The TH425 can also be modifies to use what was called "switch pitch" which was a dual stall speed torque converter. There are places that still build these. I had a friend that had his TH400 modified this way and had 3500 rpm stall and 2200 rpm stall. (he used the car for bracket racing) It probably necessary for a GT-40.

What is a "dual stall speed torque converter" and why would it be useful in a GT40?

 

[Pete T]

Stall speed is the engine RPM where the converter will transfer full engine torque to the transmission. Something like when your clutch is completely engaged. The higher the stall speed, the harder the car launches. Like engaging the clutch at a higher RPM.

A dual stall converter is set up to give you a low stall speed (like in a normal street driven car) and a higher stall speed like you would have in a high performance car (like a modifies Mustang GT) This would be useful for someone who likes to drag race a street driven car. This gives you the benefit of having two converters in one.

In a GT-40? It's probably wouldn't be useful unless you liked the occasional race from a stop light.

 

[jyrki sulka]

I think the auto trans was used in a MKII at Daytona in 1966 but didn't fare to well.

Steve

Yes, it was Daytona -66, drivers were Ginther and Bucknum, DNF

Note:
"Plan was to use automatic in all mk2`s in 1966 season . They didn`t `couse of power loss in the torque converter."

EDIT: Loaned from from 80`s GT40 book. Bullsh*t, true, or what

 

[Lynn Larsen]

I saw an episode of Two Guys Garage on Speed channel recently and they were at a shop that manufactures super high capacity torque converters. The application being talked about was very high performance diesel trucks with automatics, but if someone wants a serious torque converter, I would bet dollars to donuts that the outfit, ATS Diesel Performance, could make it. They also make their own turbos and many other parts. They do it all on site: from foundry to installation.

Lynn

 

[jyrki sulka]

Upping this; is there any more info about mkII automatics / useable modern version for high torq engine?

Cadillac TH 325/425 is out of question. Too big and complex.

 

[egoman/ Shawn Wedge]

Has anyone on this site seen the chrysler 42le trans used out of its normal chassis . This thing with about 400 horse would make an incredible drivetrain for an autocrosser or a kit.Amongst the projects we have on the go in the frozen tundra of canada is the development of a unlimited autocrosser. Actually unlimited is how we describe the creative process not the actual input of money, that is of course very limited.

 

[Mike]

All I know about the Intrepid tranny is that my brother bought an Intrepid new from the factory and had to have the tranny replaced......twice......under warranty because it left his wife stranded by the road. I get the feeling they aren't very durable. If the codes are what Pete says they are, then even Chrysler doesn't rate them very high. Doesn't look like a viable option to me....even if you could get it to work outside the OEM environment.

 

[jyrki sulka]

Seems to me Chrysler LE42 (A606?) is suitable only for west-east installation; typical FWD-box.

Time is getting short; soon must make decision manual or auto.
Health problems with left foot outlogs HD clutches, at least very heavy one`s (to use). That one reason for automatic.
Second one is engine`s high torq output; UN1 or Audi-Porsche -type is not long lasting solution.

And of course it woud be nice to now more about original 2-speed(?) autobox

 

[Mike]

I don't know a whole lot about them, so I'm completely out of my realm here, but what about some of the newer Tiptronic transaxles? They are essentially automatics from what I understand. The only area that may be tricky is geting them to work outside the OEM environment. Maybe Carquip Erik knows something about this?

 

[John Milmont]

I was shocked when i read that someone was thinking of using the dodge/chrysler trans. My experiences with that trans is that it must be one of the worst of all time. I think a lot of work would have to be done in order for that trans to handle any power as it seems taxed very heavily in the intrepid as-is. I think the biggest issue with the trans is heat since its known that the life of the trans can be extended much longer with frequent oil changes...

 

[Paolo-LoveGT40 Modelworks]

noo Jyrki..manual please...