4 Speed w/o Overdrive

G

GeneBob

Senior Member
Is there a 4 speed non-overdrive transmission that will fit into the Model A? I have a 1935 3 speed plus a separate overdrive and have been considering going to 4 speeds with a higher speed rear end ratio in order to eliminate the separate overdrive unit.
I am afraid of the truck 4 speeds because of the granny low. There were apparently some Jeep versions of the T170 trans that were 4 speed non-overdrive but I have no idea if this would work.
Any suggestions?
Thanks, GeneBob
 
I'm sorry that I have no details for you but I know that there exists and is a popular swap a f 150 4 speed but it is different in that it is 3 speed with OD not a granny. I'm sure you are going o be deluged with details from more knowledgeable guys.
 
The Toyo TK4, used in some early Ford Rangers is a 4 speed w/o OD. Probably used in other vehicles also.
 
Why would you not want an overdrive gear and preserve your current rear end ratio? As mentioned above, the F150 is a popular conversion. Someone else may chime in with names of individuals who sell these kits.
 
katy said:
The Toyo TK4, used in some early Ford Rangers is a 4 speed w/o OD. Probably used in other vehicles also.
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Hmmmm. First real suggestion.
I am surprised there isn't a trans from the 1950's or 60's that would work.
Thanks.
 
Living in Colorado as you do, I can't imagine a better set up than you have, 3 speeds and an OD = 6 gears to choose from. When driving in CA mountains 2nd gear and 2nd OD is perfect and on the open road, in OD will go faster than I care to drive.

Just my opinion and worth every penny
Richard
Anaheim CA
 
The T-10 was the first smaller 4-speed made for cars and it's based on the old T85. It was first used in Corvettes around 1957. All the old 4-speeds were for trucks back in the day so they are very big and mostly unsynchronized.
 
A top loader non overdrive 4 speed from a mid to late '60's Ford would be a good choice. All 4 speeds are synchronized and a shift tower from a Jeep T-176 will fit with very little mods to the top edge of the case. Don't know about adapting it to a Model A but adapters are available for flathead V8's.
 
51504bat said:
A top loader non overdrive 4 speed from a mid to late '60's Ford would be a good choice. All 4 speeds are synchronized and a shift tower from a Jeep T-176 will fit with very little mods to the top edge of the case. Don't know about adapting it to a Model A but adapters are available for flathead V8's.
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This sounds interesting. I assume you are talking about the famous "top loader" 4 speed that was used for performance upgrades in the 60s and 70s. I put one in my 68 Mustang when I was young. It never occurred to me that the same trans could be adapted with the top mounted shift tower. Since my car has a 1935 trans, maybe the flathead adapter combo could use the same adapter?
Like I said, interesting. Thank you.
BTW, this adaptation would leave the side shift shaft holes to be plugged?
Thanks again.
 
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GeneBob said:
This sounds interesting. I assume you are talking about the famous "top loader" 4 speed that was used for performance upgrades in the 60s and 70s. I put one in my 68 Mustang when I was young. It never occurred to me that the same trans could be adapted with the top mounted shift tower. Since my car has a 1935 trans, maybe the flathead adapter combo could use the same adapter?
Like I said, interesting. Thank you.
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Had one from a mid '60's Mustang that I installed a Jeep T-176 shift tower on. There are several threads around that had a copy of an article I think from Hot Rod about the conversion. I was going to install it with an open drive line in my '39 p/u with an 8ba. Model Engineering makes a sweet adapter that bolts to a 59 series or 8ba with a truck or Merc half bell housing. The Jeep **** tower also has a switch for reverse lights. Sold the trans, shift tower, and adapter to a guy down under.
 
I'm sorry that I mentioned the F150 box, I misread your post thought you wanted 3 speed WITH overdrive. That said, I'll buy that overdrive if you don't want it. I think that one of the best set up is a T5 4 speed With overdrive transmission. About a billionn T5s have been built for Mustangs and a whole lot of other things the S10 unit works for the model A because the shift tower is farther forward I could go on but I gotta go to bed. I'm sure there are others that can chime in (you can also search here on Ford Barn, I know I started a long thread about it awhile back.
 
If you end up using the Jeep shifter keep in mind there were 2 different shifters each with a slightly different angle. One may work out better for you than the other.
 
The Ford top loader evolved a lot over the years. In the early 70s, Tremec in Mexico took over the production of the design and aided in development of follow on designs like the HEH & RUG types in the 170 series including the T176, 177, & 178. The Jeeps used these 176/7/8 series in several applications mating to transfer cases for 4WD applications. Ford used a lot of 170 series SROD, SMOD, and TOD but they wanted the overdrive gear for the later applications using smaller engines and trying to affect fuel mileage to their advantage. They changed the shift arrangements to fit the design applications that the customer needed. The design was adaptable just like the T4 & T5 designs.
 
There is a lot of interesting information here. I asked the question because it seems like the T5 and T170 transmissions are getting hard to find. I thought a different approach may be tried; a higher speed rear end ratio with a standard 1:1 top gear in a 4 or 5 speed transmission. I am not a transmission guy but the Jeep version of the T170 caught my eye as a possible swap but it seems that no one has done this.
I think we need the next transmission swap kit for our cars.
It seems like a long shot but with the Burtz engine project becoming so popular, maybe an aftermarket transmission that is more like the T170 or T5 and more transmission than the improved original offered by Mitchell is possible.
 
Hi Gene,

The answer to your question is somewhat convoluted.

I’ve been exploring the Jeep T176 and Ford iron case toploader transmissions as a possible solution to the scarcity of the Ford T170 RTS/TOD.

The conversion using a Jeep T176 is certainly doable as it shares many of the attributes of the T170, they are the same family of transmission. The issues with the Jeep trans are:

1) The input shaft is much longer than the T170 and with different spline size
2) The output shaft is splined for direct coupling to a transfer case. This may or may not be an advantage, I’m still investigating.
3) The rear of the T176 case has a bolt pattern that is different from the T170. Therefore, an adapter plate that is different from the commonly available T170 adapter plate would have to be fabricated. Alternatively, the rear of the T176 case could be drilled/tapped for the T170 adapter. Either way some fabrication is required.
4) The Jeep T176 uses a smaller front bearing. Therefore, the front bearing retainer is smaller and may require an adapter or bushing to make it fit the bellhousing.

Another option, as mentioned by 51504bat, is using a Toploader with a Jeep T176 top (shifter). As I mentioned in our PM discussions this would produce a 4 speed with the same dimensions as the T170. This same configuration can be used on an Iron case O.D. Toploader with 3rd and 4th being reversed in the shift pattern. The problem with this configuration is:
1) If using a closed driveline (torque tube) the area of the output shaft, just behind the rear bearing, has to be re-splined to use with the Model A u-joint. The iron case, car version O.D. is necked down too small, in this area, to be re-splined. Meaning the output shaft would have to be replaced with a trucks output shaft, cut, and re-splined.
2) I’m not sure about the V-8 car (non-O.D.) output shaft diameter but I believe they are bigger and could be re-splined.
All the conversions I’ve seen, using a Jeep T176 shifter on a Toploader transmission are using an open driveline but there’s no reason, I can see, that a closed driveshaft couldn’t be adapted, same as the T170.

The reason I said the T176 output shaft may or may not be an advantage is:
1) Compare pic of T176 shaft to T170 shaft cut & re-splined.
a. It may be possible to use the T176 shaft with a modern 1310 series u-joint. I’m still investigating this. The problem is the T176 has an odd 23 spline shaft and it may (or may not) be difficult to adapt this to a yoke that can be used inside the clam shell but it certainly looks promising.

Article on toploader with Jeep T176 shifter:
https://www.jalopyjournal.com/forum/threads/ford-toploader-shifter-conversion.1035578/

Tom

Also, I just splined that shaft pictured a few days ago. While I have my lathe and mill setup I'm going re-spline the remaining 4 shafts I have. As soon as I find some T170's I'll be building them. Still working on the house though. Gotta keep the wife happy.:)
 

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Malak,
You are the most knowledgeable on this that I have seen. I am raising the question to see how people in this crazy hobby are approaching it. I have wondered what is next for transmission choices and have not seen much discussion on it. Thank you for looking forward to trying to find an answer.
If I were a purist, I suppose I would stick with the Mitchell update/upgrade and kudos to them for building what they build but I wonder what the performance upgrade looks like in the coming years.
Thanks again for your efforts.
 
Another option if you can find one in the states, is an early Volvo 4 speed, with a AA bellhousing they are the same length as a model A gearbox, do a search in the Jalopy journal. They are a popular swap here in Europe
Paul
 
Skip65, That sounds interesting too. May be hard to find but interesting. I thought I saw that trans used with an overdrive unit mounted to that back of it in a post somewhere.
 
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