Thiokol, C4 Auto Transmission to a OC-4 Manuel Trans

[corkuck]

Hi and hello I'm having thoughts of installing a c4 Automatic Transmission in front of, but yet leaving in the OC-4 manual transmission within a 1965 Thiokol Spryte. The first reason would be for the ease of shifting from Forward and Reverse. The other would be to have the auto trans shift to higher gear/s on it own, not having to stop to deal with the lack of non-syncros in the OC-4. I would also like to know its effect on low end and top end travel speeds. Would anyone mine sharing your experience/s, thought/s, hearing of this being done?

Pictures of the Cat and Transport Attached.
Thanks RK

 

[Bulldog1401]

Sounds very doable, in fact I have been considering doing the same to mine. Let me know how you make out!

 

[Snowtrac Nome]

you would be able to split all 4 gears by 3 wich would be cool when tackeling rough terrain and an auto shift down when loaded would also be nice it should not affect top end as its a 1to 1 ratio in most transmissions as is the same in an auto less a little slippage through the torque converter your torque multiplication will be a lot higher with the fluid drive trans also i thiink its a great idea and with that set up if you have to cross rough terrain you will be able to choose just the right gear to cross with out over revving or lugging.

 

[corkuck]

Great thoughts, things I would have never thought of on my own. Someone out there has had to have done this before now. I kind of like the park idea the auto has. But surly wouldn’t use it on steep inclines that’s for sure. But it would be nice to put it in park to open and close the gate. Not having to worry that it’s chasing or beating you to the gate and opening it for you.

/rk

 

[tomelroy]

First off let me say that is one great looking setup you got there...that bus and cat combo looks great...

I have an IMP that has had the same conversion you are talking about. I have not run it yet, but as soon as i get the tracks on i will let you know. Nutsteer also has done the same thing to his IMP. From what i have heard it works great.

 

[corkuck]

Yes we absolutely love the bus. It’s just the thing, to haul the winter fun too and from the cabin or with in five miles of it. These two 1976 Liquid Fire John Deere’s are sisters and are just one serial number off of each other.

/rk

 

[Snowtrac Nome]

Yes we absolutely love the bus. It’s just the thing, to haul the winter fun too and from the cabin or with in five miles of it. These two 1976 Liquid Fire John Deere’s are sisters and are just one serial number off of each other.

/rk

you ain't going to believe it but i have a cyclone 440 looks just like those on my connex it's what i got around on when i moved here i pou a 136 x1 track under it and a mountain cat suspension under it worked great but i let somebody borrow it and he brought it back with a burned piston so now i have to find a new engine for it

 

[JimVT]

on my JD I plumbed a line from the engine coolant to the handel bars and back. Worked great after purging all the air out.
jim

 

[longbed454]

Nice looking set up!!!!

 

[dlmorindds]

I have aThiokol 1402 with a Pontiac Sunbird 4 banger with the 3 speed auto in front of the existing c4 manual tranny. Goes like hell but I really only use about 3 of the possible 13 gear combos

 

[Snowtrac Nome]

I have aThiokol 1402 with a Pontiac Sunbird 4 banger with the 3 speed auto in front of the existing c4 manual tranny. Goes like hell but I really only use about 3 of the possible 13 gear combos

do you have some pics would love to see how you did italso is your motor the little iron duke 2.5 or some other motor

 

[corkuck]

The John Deere snowmobile having their flat tracks, are terrible absolutely terrible in deep snow. Would love to know where to get and what to change out to give them even just a little paddle and suspension?

Running the sleds hot water though the hand grippes to heat up the old fingers that’s a great idea, never thought of that. The heats right there why not use it, great idea?

Looks like I need to start looking for a Ford C4 Auto Trans to have it installed by fall. Still looking for others that have done this that can offer more thoughts and ideas for me to do this.

Does anyone know where I can get the big 3 inch tall rubber cone shaped door bumper stops that look original with the cat? (see bottom right on rear picture of cat) So when opening the doors they will hit the rubber bumper and the outside mirrors, windows and side of the cat?

I’m thinking of taking off the rubber bumper and using those gas filled type hood shock/rods what ever you call them.

Thanks to all of your help, good words and comments.

Here are some more Cat pictures.

/rk

 

[Snowtrac Nome]

the suspension i used was a 136 inch mountain cat kit for a 95 wild cat 1 think i used a hex shaft from an 80s vintage liquifire and pressed on a/c drivers the only complex part was the drive axle every thing else bolted up and i had to cut out the back of the tunnel and add in a tunnel extention on the back ride was vastly improved and it would go like a sno trac in deep snow more than once i would pull up next to to a stuck rmk and stop make a loop than get off and help free the rmk it was always lots of fun to do that also till the engine got burned it always started with no more than 2 pulls. will get some pics tomorrow

 

[Lia]

First off let me say that is one great looking setup you got there...that bus and cat combo looks great...

My thoughts exactly!

 

[Lia]

Yes we absolutely love the bus. It’s just the thing, to haul the winter fun too and from the cabin or with in five miles of it. These two 1976 Liquid Fire John Deere’s are sisters and are just one serial number off of each other.

/rk

I think it's real neat that you put the back of the bus on the back of the front cab...

 

[corkuck]

the suspension i used was a 136 inch mountain cat kit for a 95 wild cat 1 think i used a hex shaft from an 80s vintage liquifire and pressed on a/c drivers the only complex part was the drive axle every thing else bolted up and i had to cut out the back of the tunnel and add in a tunnel extention on the back ride was vastly improved and it would go like a sno trac in deep snow more than once i would pull up next to to a stuck rmk and stop make a loop than get off and help free the rmk it was always lots of fun to do that also till the engine got burned it always started with no more than 2 pulls. will get some pics tomorrow

Supper, great information!!! This is a good place to start, looking forward to those pictures. What about the paddle distance clearance at the top of the tunnel drive going around the drive sprocket? It already looks very close without any paddles? Did you use some other smaller drive sprockets to get the clearance you needed?

 

[Snowtrac Nome]

i do believe i had to use the smaller power sprokets the ac sprokets are 1 inch hex and the jd shaft was somethhing like 1 1/16 i took the shafts in to a machine shop and had one modified can't remember if dave turned down the a/c shaft so the jd bearings would work or milled the jd shaft so the sprokets would work. you can't use your shaft as its round but keep it for a template a worst case scenarrioyou can have a new shaft made out of 1 inch hex and you will need a template

 

[Snowtrac Nome]

here are the pics showing my conversion the track is a 3/4 but i think thhere is room for a 1 inch one of the other things i did was switch from the stock 7 link wide chain to a 9 link i would burn out a chain in a year after the 9 link chain went on i had no more problems

 

[Snowtrac Nome]

here are the pics showing my conversion the track is a 3/4 but i think thhere is room for a 1 inch one of the other things i did was switch from the stock 7 link wide chain to a 9 link i would burn out a chain in a year after the 9 link chain went on i had no more problems

forgot the darn pics again

 

[corkuck]

Great! Now you have just given me two more projects to do before fall. If they weren't such good running sleds I would just move on with something newer. Thanks so much I love it. I do think I will put some 1" aluminum angle on the track run it around and see if it clears. Then proceed with the proper depth of paddled track using your design. Thanks again for your pictures, time and information. I'm all over it J.
/rk

 

[wannagoflying]

RK, Great looking Spryte.. When considering the best build for my project, I too choose to add the C4. After many discussions with Pat of Spryte Improvement and the late Phil Sharpe of Sharpe Engineering I was sold on the addition. The fabrication to set the C4 required coping the existing #2 horizontal 3" cross member and I added one between #2 & #3 for support and resting of the transmission tail. I considered boxing out the pan, but decided to cope more than needed and would disconnect drive shaft and raise tail to drop pan if needed. I will look for more photos of the engine and transmission in the frame before powder coating. The year has been slow on progress, but have the bug to get started again now that all the snow is leaving the Sierra's.
John

 

[corkuck]

Wow great pictures of the needed cross member modifications and your additional one you added. I had no idea that I would need that kind of clearance, but it make sense though. Better to find out now then later I guess. I did assume that I would need something for the transmission’s tail to bolt to, but thought I would have room for the transmission pan.

I to emailed Pat and receive a great reply from him, isn’t he great? I know very little of the man but his is a great one.

Just returned home from picking up a Ford C4 transmission, rebuilt 7000 miles ago for $200.00. Still feeling pretty good about the project thus far. Even with the modification you have shown. Now I need to find a drive line to go into the transmission.

Thank you for your comment on my Spryte! Made me feel goodJ. Looks like you are doing a bang up job on your project that’s for sure. The older you get the harder is seems to get things done.
/rk

 

[wannagoflying]

Thanks for the complements.. As you can see in the photo the tail cone is about .75" higher than the original driveline position. Are you going to use the original brake? I've made provisions for it to mount on the now 4th cross member. Are you located in UT?

 

[corkuck]

Why I am from Layton Utah good detective work! Thank you for the picture, I do see the height difference that you have pointed out. I have yet to decide if I will use the original brake or not, but right now I would have to say yes.

Let me tell you the latest in my adventure. I bought a Ford C4 two days ago for $200.00 (Picture in wheel barrow). But then I started doing some of my own detective work and found that the C4 was replaced by the Ford AOD “Automatic Over Drive” introduced in 1980.(Picture of the new AOD in back of truck) So now for $250.00 today we have a AOD w/flywheel and a cut off driveline. Don’t get the Ford AOD confused with the Ford AODE “Automatic Over Drive Electronic”. Your old straight six will not have the electronics to run the AODE.




The C4 has gear ratios of.

• First: 2.46:1
• Second: 1.46:1
• Third: 1.00:1
• Reverse: ?

The C4 was replaced in 1982 by the C5, which was essentially an improved C4 with a lock-up clutch in the torque converter to improve highway fuel economy.

The AOD replaced the majority of Ford's older transmissions, including the C5 that replaced the C4.




The AOD has gear ratios of.

• First: 2.40:1
• Second: 1.47:1
• Third: 1.00:1
• Overdrive: 0.67:1
• Reverse: 2.00:1

As you can see it has a slightly higher then 1 to 1 ratio in over drive, meaning on the flats with the OC-4 in forth gear the snow cat should also go slightly faster then a stock machine.


Have you looked into this transmission or talked to Pat about it? I don’t wish to ware out my welcome with Pat.


I would solicit for anyone that would like to chime in on this subject to do so.


Other things for me to remember are:
1. Make sure on a ford transmission you push in a rotate the converter around three revolutions, or until it is firmly seated into the transmission, or else when you start your engine you will burn up the primary transmission pump. Then you have to take it all back out again and that would be a real treat!!
2. Install a big transmission cooler.
3. Don't put the new transmission in overdrive unless you think you are on top of your 3rd automatic transmission gear with higher engine RPMs and ready to go into over drive. Other wise running the transmission in overdrive all the time won't prolong the transmissions life that's for sure.
4. OC-4’s may have weaker 1st and 4th gears so don’t abuse them with your new Auto Transmission.
5. Remember you are driving an OC-4 in the first place.
6. You may need an aluminum spaces between the engine and the trans. You do with some engines.
/rk

 

[Snowtrac Nome]

i like the idea of the overdrive just don't use it unless you are on thee flats and don't use it pulling heavy loads or in deep snow i have done the same thing in my snow trac by changing my ring and pinion gears 4th now acts like my overdrive runs great on smooth hardpack or in softer material up to about 4 inches and tops outaround about a 25mph cruise with a top end at 4500 rpm about 30

 

[Bulldog1401]

Does overdrive ratio of .67:1 equate to, say, 8350 output shaft rpm at 5000 engine input rpm? If so, will the OC4 handle that high of an input rpm without spinning a bearing etc..?

 

[Snowtrac Nome]

the only thing spinning that fast is your pinion gear if you have good oil preferably synthetic i don't see a problem.

 

[corkuck]

Good thought's everyone! Thank you for your help. I'm still moveing forward. Looks like the going rate for a Ford AOD rebuild kit is about $200~$300 depending who and what.

/rk

 

[wannagoflying]

RK,
Yes I spotted the UT plate on the car.. we will be in Brian Head late June thru early July. May drop in for a progress check if the family agrees to visit SLC for a getaway trip. Great find, I'll be curious to see how it works out. My engine and C4 were a package from a 68 Mustang upgrade project. Keep us posted.

 

[corkuck]

Oh duh!!! Utah Plates only obvious never was trying to hide anything. Don’t know how far along I will be when you are in Utah but hey look me up. Russell Kuck Layton Utah in the phone book also. I’m also working on turning a Greyhound Bus into a Motor Home this project that is taking most of my time right now. I like to buy too much stuff that’s the problems. Dreams and time, too much of one and not enough of the other.

/rk