Mitchell overdrive

[flathead47]

I am thinking about installing a mitchell overdrive unit in a 46 - 48 ford convertible. Does anyone have experience with this, installation tips, pictures of installation , was it worth the effort. Thanks.

[oldford2]

I am considering one for our 46 so will be interested in the response to this post. I understand they are a quality gear changer and relatively easy to install. John

[uncle max]

Five hours to install - no looking back. Literally.

[John T]

Have one in my 38 Ford and it is great.

[52merc]

i believe theres a couple of ratios that you can get with this set up hopfully someone who has one in a car like yours will advise trev

[jerry grayson]

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Originally Posted by oldford2

I am considering one for our 46 so will be interested in the response to this post. I understand they are a quality gear changer and relatively easy to install. John

Most 46's have a 3.54 rear gear and an overdrive is going to result in serious underpower.

[Bruce Compton, Canada]

I have one in my "36 and it's great. My '36 has a 3.78 rear and I have the "36"% Mitchell. Overall I believe they are a well built rugged overdrive that provides a viable option over the pricey and somewhat fragile Columbia if you're not into counting judging points at a car show. Before you order one, do the math on their advertised ratios as they think that overdrive "ratio" and "reduction" are the same. In Reality their "36 % " reduction is actually around 29% ( same as the Borg-Warner and Columbia ratios) while their "26%" is really closer to 20%. If your rear end ratio is 3.78 or higher, I'd suggest getting their 36%. It makes a huge difference in driveability that you will really enjoy. Bruce

[52merc]

i think you will find its 3.78 standard ratio for 46fords

[flathead47]

My 47 has a 4.11 rear gear and is basically a 50-55 mph car. I have considered the 3.54 rear gear as an option , but the mitchell overdrive seems like a interesting solution to easily obtain a 65 mph car. I do not want to modify the floor of the car or have any clearance problems with the installation so that is why I was hoping there would be some pictures out there from someone who has installed one in a 46-48 ford.

[flatmotor40]

I put one in my 40 conv and it was a 36% and it does great and if you see a long hill just speed up a little and it will do just fine.Sue was really helpful because I bought it and it was a year or so before I finished the car and they siad they would make it good anyway so great people to work with

[flatmotor40]

I forgot ot tell you I oped for the cable because I didn't want a hole in the new floor

[Django]

I saw their ad in the V8 Times and was intrigued myself. How much are they?

[John T]

In my 36 Coupe I have a 354 rear and a 36% Mitchell and it works fine, but I do have a approx 370 cu. in. flathead for power.

[38 coupe]

Does anyone have pictures of the Mitchell installed under their vehicle and of the control, either cable or shifter?

[41PICUP]

I have one in my 41 pickup, running 3:54s, love it.
Easy install, take oout the old torque tube and driveshaft, then bolt in the Mitchell.
Any questions, call and talk to Sue Mitchell, she has all the answers, good people to deal with. Cost is about $2100. Either 26% or 36% overdrive.

[38 coupe]

Thanks for the picture. That looks like it would hit the floor under my 37 (and 38 and 39 and my Dad's 40). Does anyone have pictures of one installed under a passenger car?

[CarPapa]

Wanted to use one in my '34 sedan, but would have had to cut the seat riser and floor. Decided against it.

[Walt Dupont--Me.]

Hey John T, tell me a little bit more about your 370ci flathead. That really snapped me awake. Walt

[52merc]

me to !!

[flatmotor40]

What I had to do was move the shift arm to the bottom instead of top so it would not hit the floor when you hit a bump or someone was in the bask seat.But I had put Posie reverse eye springs on mine and it lowered it a little but teh only difference is the engage you push in instead of pull out the cable.Sue was a great help and I used syn 90w oil in mine

[38 coupe]

flatmotor40, can you post pictures of your installation? That would be great.

[19Fordy]

Originally Posted by 38 coupe

flatmotor40, can you post pictures of your installation? That would be great.

Yes, Please do. I would like to see what the entire unit looks like installed -including the shift mechanism. Thanks.

[Kahuna]

I also want to see the 370 CI flathead

[40Pickup]

Not a Mitchell overdrive, perhaps it will interest anyone anyway.
Built my from a Volvo 240/740 (Laycook) overdrive. Mounted it in my 40 pickup, I use an electric switch to activate the one seen in the photo.

/40Pickup

[Django]

Originally Posted by 40Pickup

Not a Mitchell overdrive, perhaps it will interest anyone anyway.
Built my from a Volvo 240/740 (Laycook) overdrive. Mounted it in my 40 pickup, I use an electric switch to activate the one seen in the photo.

/40Pickup

Very interesting! Can you give us more details on what you had to do to make it work?

[John T]

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Some times I hit the wrong key. Should have been 270 cu. in.

[Kahuna]

40Pickup
Is that a lockout switch on the shift housing to disable the O/D in reverse?
Thanks
Jim

[40Pickup]

Originally Posted by Django

Very interesting! Can you give us more details on what you had to do to make it work?

Let me come back later, Santa Claus knocking on my door.
Merry Christmas to you all.

/40Pickup

[Mart]

Originally Posted by Django

Very interesting! Can you give us more details on what you had to do to make it work?

I, too, would be VERY interested in the details of this conversion - I have all the parts laid out in my garage and am about to try and make one myself.

I must say your conversion looks first class and would appear to be a neat and efficient unit.

Do you have any pictures of:
The adaption of the torque tube to the front of the unit?
The adaption of the driveshaft to the front of the unit?
Mods to the tailshaft housing?
The final driveshaft from the unit to the diff pinion.

Some questions..
Was any resplining involved?
The positioning of the unit near the rear end of the torque tube - is there an advantage to this, or could the unit be fitted almost anywhere along the length?
Is the lubrication of the unit self contained or shared with the axle?


I envisage mine being a home brew job with lots of welded up shafts and parts, with the od unit towards the front of the shaft.
To be able to see details of one already made up would be a great advantage.

Thanks in advance, hope you can help.

Merry Christmas.

Mart.

[40Pickup]

Originally Posted by Kahuna

40Pickup
Is that a lockout switch on the shift housing to disable the O/D in reverse?
Thanks
Jim

Yes, quite true Jim!
I use the same function that is as original in the Volvo. So the O / D can only be linked to the (in this case) third gear. In low gear, the risk that it will be to low oil pressure in the O / D, and you can burn the clutch on the O / D. The lockout switch is perhaps not necessary, but it makes it easier for my wife not having to think about this when she is driving the pickup.

/ 40Pickup

[40Pickup]

Originally Posted by Mart

I, too, would be VERY interested in the details of this conversion - I have all the parts laid out in my garage and am about to try and make one myself.

I must say your conversion looks first class and would appear to be a neat and efficient unit.

Do you have any pictures of: = For the most part, I take photos while on what I do, but unfortunately not this time.
But I shall attempt to come back with some drawings that would clarify.

The adaption of the torque tube to the front of the unit?
The adaption of the driveshaft to the front of the unit?
Mods to the tailshaft housing?
The final driveshaft from the unit to the diff pinion.

Some questions..
Was any resplining involved? = No

The positioning of the unit near the rear end of the torque tube - is there an advantage to this, or could the unit be fitted almost anywhere along the length? = If I understand correctly, you should keep the unsprung weight as low as possible and therefore the O / D when mounted as far forward as possible, while you have to take into account whether there is sufficient space.


Is the lubrication of the unit self contained or shared with the axle? = Self contained (ATF).


I envisage mine being a home brew job with lots of welded up shafts and parts, with the od unit towards the front of the shaft.
To be able to see details of one already made up would be a great advantage.

Thanks in advance, hope you can help.

Merry Christmas.

Mart.

Mart, hope this can help a bit, see the text above.

/ 40Pickup

[40Pickup]

Originally Posted by flathead47

I am thinking about installing a mitchell overdrive unit in a 46 - 48 ford convertible. Does anyone have experience with this, installation tips, pictures of installation , was it worth the effort. Thanks.

Flathead47, it was not meant that I would intrude on your thread.
I apologize for that!

/ 40Pickup

[John T]

Some times I hit the wrong key. It should have read 270 cu. in.

[John T]

Some times I it the wrong key. it should have read 270 cu. in.

[Mart]

40Pickup:
Thanks for the reply - drawings would be great.

John T:
Yes, you do seem to be having keyboard problems.

Flathead47: Sorry for the hi-jack.

Merry Christmas to all.. Dinner's on the table so I'll check out for now.

Mart.

[flatmotor40]

have not figured out how to send pics not good at computer need 10 yr old but no one around I'll try

[flathead47]

40Pickup & Mart no apologizes required , it is all good information ..... Thank you to all who have input with this thread so far ..... Merry Christmas to all

[jerry grayson]

Originally Posted by 52merc

i think you will find its 3.78 standard ratio for 46fords

Maybe in NZ, but 3.54 in US

[JM 35 Sedan]

[QUOTE=John T;131053]Some times I hit the wrong key. Should have been 270 cu. in.[/QUOTE

I thought maybe you meant 270 instead of 370. I built a 284 and first thought man... what in the world did he do to get to 370 ci ?

[40Pickup]

Some drawings of my overdrive conversion. Hope it can be useful!
It is free to come with questions.

/ 40Pickup

[Mart]

40Pickup!
What can I say??!!
The drawings are fantastic!

Thanks for posting them.

When I make mine I will take pics and post then here.

Mart.

[Rem]

40Pickup, that's a very nice job. What are the drawings modelled in, if you don't mind me asking?

Hi Mart, do you have the Volvo O/D? I have a couple of Triumph and Ford J-Types awaiting some investigation (I started looking while I had the '34, but perhaps I'll get onto it this year with the B). The Ford (Scimitar) one wouldn't be too useful as it has a splined output shaft, but the Triumph one has a flange like the Volvo appears to.

[Mart]

Originally Posted by Rem

40Pickup, that's a very nice job. What are the drawings modelled in, if you don't mind me asking?

Hi Mart, do you have the Volvo O/D? I have a couple of Triumph and Ford J-Types awaiting some investigation (I started looking while I had the '34, but perhaps I'll get onto it this year with the B). The Ford (Scimitar) one wouldn't be too useful as it has a splined output shaft, but the Triumph one has a flange like the Volvo appears to.

Hi Andy - my od unit came from some sort of a vauxhall or something - it has a splined output but I have the prop yoke - hopefully it's forged so I can weld to it. I have a plan in my mind, but have not cut up any early ford parts yet.
I'm pretty sure you can mix and match parts if the basic unit is the same - if the front end of the scimitar unit is more easily adaptable, you could use it with the flanged output from the Triumph unit if that is the easiest to adapt.

I'm hoping to connect to the output casing without welding a flange on so that will be interesting. Maybe I should be looking for a different output but plan on welding on a flange - something to consider I suppose.

Mart.

[40Pickup]

Originally Posted by Rem

40Pickup, that's a very nice job. What are the drawings modelled in, if you don't mind me asking?

Hi Mart, do you have the Volvo O/D? I have a couple of Triumph and Ford J-Types awaiting some investigation (I started looking while I had the '34, but perhaps I'll get onto it this year with the B). The Ford (Scimitar) one wouldn't be too useful as it has a splined output shaft, but the Triumph one has a flange like the Volvo appears to.

Rem, it is quite okay to ask! I started with AutoCAD at the beginning of -90, and uses it still. Today there are so many programs to choose from, so I'm not sure it would be AutoCad if I were to choose today!
Maybe someone has an opinion?

/ 40Pickup

[Gumpy]

going to eventually purchase one of these and change out the pumkin rear end in my 40 coupe....then can drive the car anywhere!

[Rem]

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Originally Posted by Mart

Hi Andy - my od unit came from some sort of a vauxhall or something - it has a splined output but I have the prop yoke - hopefully it's forged so I can weld to it. I have a plan in my mind, but have not cut up any early ford parts yet.
I'm pretty sure you can mix and match parts if the basic unit is the same - if the front end of the scimitar unit is more easily adaptable, you could use it with the flanged output from the Triumph unit if that is the easiest to adapt.

I'm hoping to connect to the output casing without welding a flange on so that will be interesting. Maybe I should be looking for a different output but plan on welding on a flange - something to consider I suppose.

Mart.

Hi Mart, I'm hoping that there is some swapability in the parts. Gavin was also looking at using a J-Type, so maybe we should compare notes next year?

Originally Posted by 40Pickup

Rem, it is quite okay to ask! I started with AutoCAD at the beginning of -90, and uses it still. Today there are so many programs to choose from, so I'm not sure it would be AutoCad if I were to choose today!
Maybe someone has an opinion?

/ 40Pickup

Thanks, I use AutoCAD at work, although not full-time. I have not done any 3D work on it yet - we also have Solidworks for compatibility with a customer, but I do not have access to that software. Would you be prepared to share the AutoCAD files with others for reference? I would fully understand if you prefer not to, as I appreciate the amount of work that will have gone into creating them.

Cheers, Andy

[Automotive Stud]

I installed the Mitchell with the 36% overdrive in my '47 coupe with 3:78 gears and I love it! I used the cable shift setup, so I have a '49 Overdrive T handle mounted under the dash. I did have to notch the floor very slightly under the back seat, the forward edge of the overdrive would hit the floor on bumps. It was very easy to install, but I can't give much of an idea on time, mainly because I opted to rebuild the rear springs and add spring lining while it was all apart. I also replaced the clutch and rebuilt the transmission while I had everything out. I have pictures I can post if anyone is interested.

[FlatheadTed]

This is a modification done here a lot for Model As

[FlatheadTed]

This unit is more or less the same as 40 pick-up .You will note the extended casting out the rear,As i understand it this is required for a oil reservoir for cooling .Has 40 pick up had any issues here ,

[flatmotor40]

I moved the shifter bar on the OD to the bottom and that did away with hitting the floor.It makes teh cable push in to get OD pull out and you are out of OD

[Automotive Stud]

Ok here are some pictures of when I put it in my '47 coupe. As you can see from the one picture it was close to the floor pan. I thought it would clear, which it did until you hit a bump. So you can see how I had to notch the floor under the rear seat for clearance. Now I've had no problems at all. I would definately use one again.

[40Pickup]

Originally Posted by FlatheadTed

This unit is more or less the same as 40 pick-up .You will note the extended casting out the rear,As i understand it this is required for a oil reservoir for cooling .Has 40 pick up had any issues here ,

Yes you have a point here! Well .. measured the oil level in the O / D when it was installed to Volvo gearbox, (they share the oil) came to the conclusion that the oil level was not high in the O / D and the amount of oil was low. I thought, can this work? Maybe I had to make an external oil tank, but have run now for two years without any problems. If I have calculated oil level right, so it must be raised much for reaching out to the extended reservoir. That's an advantage with larger quantities of oil just to keep down the temperature, so I think you're right here. I thought, is it a disadvantage to the high oil level?

/40Pickup

[CarPapa]

Has anyone ever put a Mitchell into a '34 Tudor Sedan? I have tried to take measurements and it seems it would require cutting the floor and rear seat riser. It looks like it would fit if there was no suspension travel, but that is not realistic. Thanks.