Speedo drive “turtle” on transmission

[rockfla]

Are there different speedometer drives between Ford & Mercury OR are they year specific I.e. 34-37 or 39-42?? I replaced one on the car and the new “used” one looks good, spins nice and free. I installed the cable into the drive and spun the gear and see the cable turning on the other end. I installed the turtle to the transmission but it doesn’t work. I can feel the cable “twitch” but it doesn’t turn!

[Tinker]

Tire size and rearend gears depict the turtle gear size more then anything. Fairly certain you can run a 28-29 Model a gear set in the later housings, the Housing may differ. If the picture doesn't come through here there is a chart in my albums.


"Turtle" housing Merc to standard ford maybe different. Just adding useless info.






Maybe a bit better rez.

[cas3]

yup, 28-48 all the same

[Newc]

Are the gears on the drive shaft all the same?? Newc

[Tinker]

Believe so. Rear end gears and tire size change the turtle gear section. Now the gear housing is a different question, surely not the same as I probably couldn't put a housing of a 41 on a 33, maybe not. Certainly zephyrs would be very different also.


Probably a good question for a guy like Vanpelts.


.

[V8COOPMAN]

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Originally Posted by Tinker

Believe so. Rear end gears and tire size change the turtle gear section. Now the gear housing is a different question, surely not the same as I probably couldn't put a housing of a 41 on a 33, maybe not. Certainly zephyrs would be very different also.


Probably a good question for a guy like Vanpelts.


.

Interesting info! DD

[V8COOPMAN]

One or two similar housings fit all Ford Products from '28-'48 to make-up for diameter differences in DRIVEN gears. Check Brattons catalog for all parts except DRIVE gears. Fred MAY have those. DD

[Tinker]

Originally Posted by V8COOPMAN

I hate when people pull ANSWERS out from where it's very dark.....and the answers are wrong! DD

Well bring us to the light?

[Tinker]

Originally Posted by V8COOPMAN

One housing fits all Ford Products from '28-'48. If anyone reads that chart carefully, not only are there different DRIVEN gears, but it appears that there are three different DRIVE gears, to make-up for diameter differences in DRIVEN gears. Check Brattons catalog for all parts except DRIVE gears. Fred MAY have those. DD

The different Diameters give the variation of rear end changes. What they do. Brattons is why I mentioned model A gears for 3.54 rear ends. Once you get into the 40's there is different gear housing. Straight verses 90. Or not. Not sure with the 21 gear Zephyr trans its the same. maybe


You can run any gear from the chart I posted. Your speedo will be off. But that is all.

[flatheadmurre]

The turtle housings aren´t all the same so if someone put a smaller gear in a housing for a bigger gear doesn´t the offset make the gear turn in the air ??
If i get it right...a different housing can put the gear closer to the drivegear to make sure they ingage properly...that´s why we don´t need to change the drivegear.

[Tinker]

Originally Posted by flatheadmurre

The turtle housings aren´t all the same so if someone put a smaller gear in a housing for a bigger gear doesn´t the offset make the gear turn in the air ??
If i get it right...a different housing can put the gear closer to the drivegear to make sure they ingage properly...that´s why we don´t need to change the drivegear.

Okay I'm on board murre. Makes sense. Like I mentioned the housing is important. gears are set. Now is there a housing change chart??? It'd be anti-ford to make new gears every yr. Not cost efficient. Housing with the same depth but different castings most likely.

[V8COOPMAN]

Originally Posted by Tinker

The different Diameters give the variation of rear end changes. What they do. Brattons is why I mentioned model A gears for 3.54 rear ends. Once you get into the 40's there is different gear housing. Straight verses 90. Or not. Not sure with the 21 gear Zephyr trans its the same. maybe


You can run any gear from the chart I posted. Your speedo will be off. But that is all.

Bratton's has been doing this stuff for a long time. They've done this "turtle" thing more than once! The pictured "9-34" housing in their ad (STRAIGHT housing...not 90 degree) is for a Model 'A' with 3.78 rear gears and 21" wheels. A couple of similar HOUSINGS fit Ford products all the way up to '48! Link to Bratton's ad below...check it out!


https://www.brattons.com/catalog.html?cat=446


You make reference to a "21 gear Zephyr trans". Fact of THAT matter is that Lincoln DID offer what are referred-to as both "25-tooth AND 26-tooth" Lincoln Zephyr gears, those two numbers referring to the number of teeth found on the front-most gear on a Zephyr cluster gear. You may know more than I do about Lincoln transmissions, so could you please enlighten me about a "21 gear Zephyr trans"? Nevertheless, most of those heavy Zeps had 4.11 rear ends, necessary to get that heavy-mass automobile rolling from a stop, yet necessitating the corresponding 2.12:1 or 2.33:1 first gear ratios unique to the Lincolns. These were both necessary ratios when facilitating the use of the available O/D. Speedometers could still be calibrated correctly using information from your chart. You'll note that 4.11 is a common rear gear ratio on that chart.


Lastly, you state that: "You can run any gear from the chart I posted. Your speedo will be off." Well Mr. Tinker, the whole idea behind using the chart you posted is so that Your speedo WILL NOT be off!.……..DD
















………….

[Tinker]

Originally Posted by V8COOPMAN

Bratton's has been doing this stuff for a long time. They've done this "turtle" thing more than once! The pictured "9-34" housing in their ad (STRAIGHT housing...not 90 degree) is for a Model 'A' with 3.78 rear gears and 21" wheels. Same HOUSING fits Ford products all the way up to '48! Link to Bratton's ad below...check it out!


Relax. I was talking about 40' turtle housings. I have ordered a bit from bratton's and Snyders. Why I brought it up on gears.



https://www.brattons.com/catalog.html?cat=446


You make reference to a "21 gear Zephyr trans". Fact of THAT matter is that Lincoln DID offer what are referred-to as both "25-tooth AND 26-tooth" Lincoln Zephyr gears, those two numbers referring to the number of teeth found on the front-most gear on a Zephyr cluster gear. You may know more than I do about Lincoln transmissions, so could you please enlighten me about a "21 gear Zephyr trans"? Nevertheless, most of those heavy Zeps had 4.11 rear ends, necessary to get that heavy-mass automobile rolling from a stop, yet necessitating the corresponding 2.12:1 or 2.33:1 first gear ratios unique to the Lincolns. These were both necessary ratios when facilitating the use of the available O/D. Speedometers could still be calibrated correctly using information from your chart. You'll note that 4.11 is a common rear gear ratio on that chart.

What I don't know I ask questions, I didn't ever say I know everything about zephyrs.


Lastly, you state that: "You can run any gear from the chart I posted. Your speedo will be off." Well Mr. Tinker, the whole idea behind using the chart you posted is so that Your speedo WILL NOT be off!.……..DD

That's the idea. If you pick the right gear, if you don't, well your speedo will work, but it won't be accurate. Why I posted the chart


………….

....


Not sure what you are getting at. Or why. You agree with the chart, but not me. I don't know you either, I might not like you either.

[flatheadmurre]

Hey guys...we here to share and sort out the issues...if you want to find they guy that´s usually wrong i´m the prime suspect...atleast twice a day i have to knock my forehead into the wall

[Tinker]

Originally Posted by flatheadmurre

Hey guys...we here to share and sort out the issues...if you want to find they guy that´s usually wrong i´m the prime suspect...atleast twice a day i have to knock my forehead into the wall

Murrie the only solid info was supplied by you. The rest is just bs supplied by a few that do T5s.

[rockfla]

SO.....
What I am pulling from ALL the above IS.......The housing I have is with a high degree of certainty is correct? My issue "most likely" is the actual drive gear?? As I read the chart......with a 16" tire, 3:54 gear set it will MOST likely be a 20 tooth gear???


I will take pictures and post this evening or first thing tomorrow morning if need.


Thanks
Rockfla

[skidmarks]

Originally Posted by Tinker

Murrie the only solid info was supplied by you. The rest is just bs supplied by a few that do T5s.

Whats a T5 got to do with the speedometer turtle thats part of the rear?

[flatheadmurre]

Originally Posted by rockfla

SO.....
What I am pulling from ALL the above IS.......The housing I have is with a high degree of certainty is correct? My issue "most likely" is the actual drive gear?? As I read the chart......with a 15" tire, 3:54 gear set it will MOST likely be a 20 tooth gear???


I will take pictures and post this evening or first thing tomorrow morning if need.


Thanks
Rockfla

What´s the number cast into your turtle now ?

[rockfla]

I'm not at my car right now BUT I do have a couple of pictures that i took of some other work I was doing and its a little hard to see in the picture because of the glare BUT It looks like " 8 L "???? I can post back this evening when I get home. Or " 8 I " maybe????

[rockfla]

"DERK".....what a bafoon.....its an 18 tooth gear I currently have on the car!!!! duhha!!!! SO my issue is a "meshing" issue between it and the speedo dirve gear on the output shaft which appears to be in good order from what I see of it when I remove the speedo "turtle"???? AS logic would tell me EVEN IF i have the wrong toothed gear the speedo "Should" work, RIght??? Just not give me an accurate MPH???