Tech Request: The Be-All/End-All Flatty/Transmision Combo post...

Let's start one here guys...

For me, I'd like to hear about what all you flatty guys are running for transmissions, why, and what it's like driving them on the road.

I want horror stories, success stories and installation stories.

I wan't to hear how you'd do it if you had the chance to do it over again and why.

And I think LOTS of people would as well.

I've heard the pros and cons of all the combos...

39 toploader,
C4
T5
70's Ford toploader,
etc...

But I'd really like to hear how they last on the road and if there are any concerns with driveability etc...

How likely am I to blow up my early trans under daily driving conditions? How much FUN can I have? Will I really need to baby it every where I go?

How much of a difference did it make when you switched to a T5? Was the swap a pain in the ass? Does it really make driving that much more pleasurable? Ever blow one up behind a flatty?

Why on earth did you choose to run an auto in a Hot Rod? 3 peddles just WAY TOO MUCH for you to keep track of? Is there any noticeable parasitic loss associated with running an auto behind a 150 horse engine?

Let's help people decide what trans to run with ALL the info available instead of just anectdotal evidence...

 

I might as well start it off with my choices so far and what I've heard...

I have a early toploader and have set up my frame for that and a torque tube. I like the nostalgic feel of the build but I'm no purist. Frankly the idea of babying the tranny and blowing it up the first time I get a little squirley gives me the pox...

I'm also not so crazy about going through all the tube shortening wackiness just for the look, and I have some ideas that could work out being pretty cool/nostalgic looking for open drive.

I also have a 70 truck 3spd toploader that is dimensially very similar to the early trans but is basically bullet-proof and is full synchro. It appeals to me because it could be hidden easily in a trad frame and driving would be a lot easier and stress free.

Now I've got friends whose opinions I really respect telling me I should run a T5 to really make driving more enjoyable. They say the flatty might last longer with the extra couple of gears and long drives will be much more doable with a combo like that.

What did you choose to do and why?

I know this stuff has been covered before in bits and pieces but I think it would be cool for other builders if it was all in one place. So PLEASE include stuff you might have posted before.

That way those that NEED the info might not miss it and make an avoidable miss-calculation in their mock-ups...

Let's get some miles on those flatheads.

 

I run a 5 speed. The steep 1st gear and 4.10 rears get it outta the hole like a rocket and the overdrive let's me average 32 mpg. I tried to make a clutch pedal outta wrenches and figured out the hard way they aren't meant to be welded. Yup, it broke.....twice. Other than that, it rocks like a hurricane and has given me plenty o miles on the ol Beater.

 

I'm using a '46 Merc three on the tree in the '27 roadster. It is built very rugged and should last forever under street conditions. It's not a speed shifter though; you have to baby it a bit going into second. All of the different trans combos that are avialable are a tradeoff, one way or another. How much do you like to shift?

pigpen

 

In my 34 Truck I used a Speedway kit to a 65 Mustang C-4 trans on a Flatty. To be honest with a 7" channel I did not have enough room to work a clutch. All in all it worked out Damn good!! In my 34 Tudor (soon to be a Koop) I will use a S-10 T-5 behind the Flatty.

 

I always stick with a 39 when running a flathead, if your running a 39 behind a flathead you shouldn't have to many problems breaking it unless your running a super flatty. They fit nice look good and you don't have to cut the K member. If you get a 39 behind anything with some power they seem to want to break large holes out the bottom of them and basically leave you with just high gear which isn't to bad since you don't have to shift anymore. If you have to drive far just unscrew the stick from the top plate and dump a quart of oil every 50 miles or so to keep the bearings wet. I have been through this process several times but thats when you could get a new gearbox for $25.00

 

1947 "59" Flathead
Aluminum Pistons
Iskenderian Cam
Edmunds Custom Aluminum Heads
Edmunds Custom Aluminum 2x2 Intake
Stromberg 97's w/Velocity Stacks
Open Individual Header Tubes
1937 LaSalle 3spd Transmission

....Of course it isn't all together yet

Originally I was going to tun a 4x2 296ci full race mill, but that would have been a pain and impractical anyway.
-Dean

 

Hey Guys,

Stock 8BA with hot ignition. woop.

'39 style truck toploader of unknown age.

3.6:1 Ford Freighter (early F1 style) diff.

Runs like a slug with the 30" tall tyres.

I've been in a mates ride with a toyota 5spd and it runs like a raped ape. I think nothing beats a 5spd in a flathead powered car, it must make all the difference. you can run with 4.11:1 rear and still get cruisy highway miles. Boy do I want one...

Danny

 

i was all up in the air about what i wanted to run in my roadster too! i'm running a 226 flat six. and first wanted to run a ford three speed with overdrive from a 80s pickup. and can't find one any place!!! sooo after checking out jim harrisons A. and talking to frank mod driver. i then really wanted a torque tube! so i started looking for 39 type three speeds. i have come up with four and can't make one out of all of them!!!!! but three of them are truck trans so i have open drive stuff for the top loaders. and shifter tops!!! sooooooo now i'm getting a gear set from DME dinnis in wv. so that is what i'm going to do a three speed 39 type with a torque tube. i did thunk about a toyota trans? sounds good to me. call fat jack about it!

 

In my 50 sedan with a 296" I run a 3 speed w/o, only thing is I don't have the switch under the pedal, governor, or the relay hooked up. I taped a toggle switch on the shifter and when I want overdrive just push the cable in and flip the switch. I like driving it like that and it gets pretty good mileage and will cruise on the interstate with the traffic with no problems at all. I love it.

Stafford

 

In my 49 Ive got a Merc cranked 3/4 cam t duece intake .
Ive got a 4spd top load from a late 60`s Mustang
damn near a bolt in.
I had stock 3.73 gears that were a little noisy so I swapped them out for a clean center with overdrive 4.10 gears .
Not great on hiway RPMs but fun on the street.

Than trans was a freebie so If I did it again I would probably put a 5 spd in for the moiney.

 

My combo?

3 5/15" x 3 3/4" = 258 ci, L100 cam, Offy 400 Heads, lightened flywheel, Toyota Celica 5 speed, 3.91 gears, 31 tall Firestones.

All new combo that will be on the road soon. The 5 speed will make a huge difference, esp with the 4-71 going on, Ill be pushing some good HP/TQ numbers, so it should really blast outta the hole and give me some economy on the open road. I figgered (correctly) a 39 trans wont last with that much going thru it, not to mention the lack of extra gears !!

Cant wait !!

Rat

 

Thanks guys...

I might have to rethink my trans now.

Let's keep it going.

What is the best trans behind a Flathead and why?

What gear ratios should you look for?

What drop between gears?

I think the Transmission is one of the seldom discussed and most important aspects of building a Hot Rod. It can make or break a driver. Let's see if we can get that info out there.

 

Hey all,

Im (soon to be) running 59ab flatty, mild cam, 2x2 intake w/ T-5 trans and 4.11 rear end (55 Ford )

I have heard this combo give great gas milage and will scoot off the line. 5th gear will let you cruise 70-80 on the freeway. I would really like to run the early stuff, but I want practicality, efficiency and the ability for long distance w/ little to no effort.

I got a 39 trans too, but think Ill let it sit for the next project....

 

I've got loads of parts collected, but still running original trannys in both my rods - for now, that's fine. Next time they come apart in a big way, it may change.

For my money, you can't beat the T5. They're cheap, light, & have two main ratio sets for use behind a flatty that are pretty good.

Here's something I posted over on Fordbarn:

This doesn't preclude you from putting the S10 tailshaft & topcover onto another T5 although you will probably have speedo issues.

There are other ratios available. The late-model Mustangs & many Camaro/Firebirds have a strong, performance-based ratio:

1st-2.95 2nd-1.94 3rd-1.34 4th-1.00 5th-0.73
or
1st-3.50 2nd-2.14 3rd-1.35 4th-1.00 5th-0.78


I also think you could adapt the closed driveline to a 4WD T5 from a S10 4x4 or Jeep with a bit of fabrication & machine-work - if you were so inclined...

 

Bttt>>>

 

Camaro T-5:

1st-2.95 2nd-1.94 3rd-1.34 4th-1.00 5th-0.73
or
1st-3.50 2nd-2.14 3rd-1.35 4th-1.00 5th-0.78

I got a Camaro T-5 and switching the tailshaft cover and stick for an S-10 type.

My rear is a 4.11; for you real "gear heads"...do you suspect any issues w/ my engine/trans/rear combo? (see above) for the gear set above? I have a tag on mine...I will check and post it

 

I have a '49 stock 239 with a T-10 out of a '63 Falcon sprint behind it in my deuce coupe. It's a direct bolt up, only change is the addition of a Mustang clutch disc. The Falcon T-10 has the linkage at the front of the tail shaft. It works great, have 3.55 gears in an 8" out back. It cruises down the freeway just like a real car.

 

Hey Crew,

Ok so your thinking about the toyota supra or celica 5spd conversion? well here is some info that may help you along, i'll swap it in exchange for anyone who can tell me what the standard ratios are for 3spd toploader boxes that came out of pickups/trucks etc.

Wxx Series Toyota Gearboxes



*W series gearboxes have a separate bellhousing.

*Different bellhousings are used to connect a W50 gearbox to an R or M series engine.

*Different bellhousings are used to connect a W55 gearbox to an R or T series engine.

*Alloy W5# gearboxes are interchangeable with each other.

*Alloy and steel W5# gearboxes are not interchangeable with each other.

*W50 bellhousings do not fit the W55 gearbox and vice versa.

*W55 bellhousings do fit the W56, W57 and W58 gearboxes and vice versa.

*All W## gearboxes after 1970 had the same output spline as the A## automatic gearboxes.

18R Toyota Four-Speed:



This is a heavy-duty 4spd that was used in 4 and 6 cylinder motors in 18R Coronas, Mark 2 Coronas, 6 cylinder Cressidas and Crowns. They're available with two different stick positions. The one in Pic 3 has the kickback shift level and the other version has the lever 2.5 inches further forward. They're very strong and won't break behind a 6. A lot of people use them behind V8's quite successfully and, even if you do break one in such an application, they can be found at wreckers for as low as $50, which makes it economical to simply remove the damaged one and fit a replacement. Some people scoff at these boxes because they were used behind 4 cylinder engines, but a closer examination reveals they're ridiculously over-engineered for such an application. If your clutch ever fails, one of these boxes will get you home quite happily as long as you don't need reverse.

Toyota Five-Speed:



This is the same as the 4 spd version but you'll note that the rear housing, which contains fifth and reverse, is bulkier. All the details about the position of the shifter, the tailshaft yoke and the bolt-up pattern are the same as for the 4 spd. In the trade, they're commonly known as a steel-case Toyota.

They came on 18R, or 2 litre engines in hatchback or mustang lookalike Celicas. They were also used in 6 cylinder Coronas and imported Crowns and in these applications they were fitted with a heavier-duty needle roller bearing in the front cluster. Unfortunately, you can't tell if this is the case until you pull it apart, but if you do and you find the roller bearing, you know the box has been in a 6 cylinder, a turbo model, or a diesel. Hopefully, you'll find a ball bearing which indicates that is was fitted to a NA 4 cylinder and has had much less power put through it.

Finding the lower rated box and refitting it with the stronger roller bearing is ideal. They come in 3 first gear ratios. Versions fitted to the 18RG engines, which were Yamaha headed engines, were fitted with a 3.0:1 ratio, which is very high. These versions are fairly rare but can still be found if you look hard enough. There are also 3.25:1 and 3.5:1 versions available. As with the 4 spd, people fit them to V8's, but its not a great idea because, unlike the 4 spd, they're quite expensive ($400). A better choice is the Supra, which is stronger and doesn't cost much more.

Toyota Supra Five-Speed:



These boxes first appeared in Australiain 1984 in the 4 cylinder Corona. They were also fitted to Celicas and, obviously, Supras. Both 4s and 6s had exactly the same version, so everything said about using 4 cylinder Toyota 5 spd units applies to the Supra box. There was at least 4 ratios in them, starting with an extremely low 4.0:1, which was fitted to commercial vehicles, following by 3.7, 3.5 and 3.28. They have the same length input shafts as the other Toyotas and are virtually interchangeable with the steel-case. However, they do have a different bolt pattern. As is commonly known, these boxes are extremely strong. They're much stronger than a steel-caseToyota. Straight from a wreckers, this box will cost about $500, but a stripped and checked version is about $700.

There is another, extremely rare and much stronger, version of this box that was fitted to a 3.0 litre Twin Turbo. Its about half as big again as a normal Supra but apart from that it looks the same. It has been known to handle in excess of 550HP with no difficulties. If you can find one, you'll have to pay something like $1500-$2000, but they are very rare.

The Supras' shifter also came in 4 different locations:

The above transmissions feature a range of gearshift positions as standard. Measured from the front face of the transmission these are : 18, 20, 21, 21.5 inches.

Gear Box Ratios, Years, Weight and Application Specs

Please click on the attached pdf for a printable table of all box years, cars they came in, gear ratios, weights and HP rateings as per their original application.

Danny

 

WOW Psychobilly Boi you really did your home work!! Thanks!!

 

Wow great info...

Let's keep it going.

Man! I am still really torn...
I hear all the benefits of the T5, I find one in the paper for $100 and I think 'I'm SOLD.'

Then I go home, look at my frame with the torque tube and my flatty mated to the 39 toploader, and I think 'You can't bastardize this frame with a modern trans.' And then there's the 'you don't have to baby-it post.'

I really don't know what to do for myself even though the T5 really seems like a no-brainer.

Maybe this info will help somebody ELSE.

 

My 8ba is running a 37 toploader. I am totally pleased with it. Good torque off the start and will run 65-80 mpg @ 18 miles per gallon. I am running large dia 15 inch tires with it.
No problems with popping out of gear here. I am watching this post very closely. Yes, it sure would be nice to grab another gear at about 50-55 mph.
Great post!

 

yeah but think once the body is on you won't see it. you can convert the rear end to open drive and still have the banjo. You can have a reliable transmission or deal with busting gears in the toploader. I already made the decision I have a t-5 in my garage. You don't have to baby the toploader, but you'll be picking gear teeth outta the tranny like I saw jimmy shine doing at MM a couple years ago. He had to drive home with only 3rd gear.

 

Here's a small pic of a Jeep T5 & a 4WD S10 (Jeep still has transfer case on it). As you can see, these are set up with the forward shifter, but a tailshaft for a transfer case. 4WD S10/S15 are similar, but longer. It would seem to me that adapting this to a torque tube/closed driveline would be fairly straight-forward requiring a bit of fabrication & machine work to sort the U-Joint issue.

The best of both worlds?

 

hey crew,

ahah what decision? from someone with a early toploader, id beg, get on my hands and knees and pay out some dollars to get a 5spd anything in my ride. no synchro on first, wierd hyper ratio truck first gear, the grand canyon jump in ratio between first and second, the lack of OD. yech. my ride doesnt have any components on it made after 52 but id whack a 5spd in there quicker then anything.

one of those things that makes the car so much more enjoyable to DRIVE and thats more trad the using old shit for the sake of it. *breathe, breathe*

Danny

 

I'm running a 48 f1 tranny open shaft/w 39 shaft for the clutch hope it all works

 

Thanks guys keep the opinions coming...

I'm leaning back towards the vintage trans now.

 

Random thoughts: Flatheads need more than three gears--perfect but expensive trad setup would be Lincoln close ratio gears, 4.44 rear, Mitchell-Columbia-Lincoln OD to keepit alive on highway...$$$.
Best affordable trad is 3.78 with 28 tooth gears, at least with tires not too far fron 6x16. This is decent over whole range of use--but a higher high is still missed. Mitchell type setup can always be kept in the plan as a later addition...
Durability is fine with small engines and sane (but not conservative) driving--you really don't want to dump the clutch at 6,000, but you don't have to baby a good one.
Big secret not mentioned in the general literature, applicable to all passenger car trans made since maybe 1930, but especially applicable to the '32-48 Ford and the '55 Chevy three speeds that rodders have blown by the thousands: END PLAY.
Spiral cut gears have powerful fore-aft thrust on the gears. If you have end play in the gearsets, this clearance is SLAMMED shut on each shift, causing broken gears and cases.
Other, less secret secret, is good tight bearings--any slop in gear engagement lets the gears try to climb over the other gears' teeth, leading to explosive failure at some point.
Jumping out of gear is caused by wear somewhere, or several somewheres--since new gears are now scarce and expensive, sometimes the cure involves simple machine work, like machinig surfaces of the center input/output shaft bearing if badly worn. Most of the trouble areas require simple bearing replacement.
Tricks of the past include milling rear of case to slide rear bearing forward to eliminate play.
I've got a semi-tech article on adding 1st gear synchro to these things! This is taken from an article on Manning's semi-famous early fifties sports racer...

Higher tech: we don't need smaller cellphones--we need commercial torque tube adaptations for toploaders and C5's. Have your cake and keep full function suspension...