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???

[Kube]

The drive gear is identical amongst the passenger cars. Simply locate the proper driven gear, install it and you're done.

And yes, with the "wrong" driven gear, your speedometer should operate albeit inaccurately.

[rockfla]

SO....last stupid question and/or double checking, logic tells me that the turtle is mounted/oriented with the speedometer cable end pointing downward or toward the left side of the vehicle?? OR I didn;t check BUT the "turtle" can only mount one way???

[Mart]

The output sticks away from the torque tube in the same direction as driveshaft rotation in forward motion.

That's to the left on top or right on the bottom or down on the left and up on the right.

It can be fitted backwards and the speedo will only work in reverse.

Mart.

[rockfla]

Originally Posted by Mart

The output sticks away from the torque tube in the same direction as driveshaft rotation in forward motion.

That's to the left on top or right on the bottom or down on the left and up on the right.

It can be fitted backwards and the speedo will only work in reverse.

Mart.

So is this the "correct" orientation???

[Kube]

Originally Posted by rockfla

So is this the "correct" orientation???

yes

[V8COOPMAN]

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Originally Posted by rockfla

So is this the "correct" orientation???

Yes, CORRECT orientation! DD

[V8COOPMAN]

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 16" tire, 3:54 gear set it will MOST likely be a 20 tooth gear???

Thanks
Rockfla

What is the actual descriptive size of your 16" tire, i.e. 6:00 x 16", or 7.50 x 16"? According to the chart, most of the normal or "near-stock" sizes should require a 20-tooth gear, although a large-outside-diameter tire like a 7.50 x 16" with a 3.54 would take the 18-tooth gear. DD

[flatheadmurre]

And the drive gear is locked in place as it should ?
If the snapring holding it has come loose you get issues with it moving and loosing contact...

[rockfla]

Originally Posted by V8COOPMAN

What is the actual descriptive size of your 16" tire, i.e. 6:00 x 16", or 7.50 x 16"? According to the chart, most of the normal or "near-stock" sizes should require a 20-tooth gear, although a large-outside-diameter tire like a 7.50 x 16" with a 3.54 would take the 18-tooth gear. DD

They are 6.00 X 16's. I just looked at the chart and 3:54 with 6.00 x 16 both 4 and 6 ply tires shows an 18 gear, or am I reading it incorrectly???

[rockfla]

Originally Posted by flatheadmurre

And the drive gear is locked in place as it should ?
If the snapring holding it has come loose you get issues with it moving and loosing contact...

Thinking over what I have previously done I believe this may be the issue as I think I remember it being able to move back and forth quiet a bit???? I will pull and check it tonight. Hopefully IF the snap ring is missing on the good one I can rob one out of the "bad" one???



Thanks to everyone for your help and advice, I may also be looking for a 20 tooth gear

[V8COOPMAN]

Originally Posted by rockfla

They are 6.00 X 16's. I just looked at the chart and 3:54 with 6.00 x 16 both 4 and 6 ply tires shows an 18 gear, or am I reading it incorrectly???

You DID read that correctly when you look at the 6.00 tires and the 40 17270 turtle. I take that to relate to MODEL 40 ('33&'34). If you look a little further down at the 6.00 tires and the 68 17270 turtle (which SOMEHOW seems to relate to MODEL 68...1936 model year AND LATER), the chart indicates a 20-tooth. There's obviously a part of this puzzle that is escaping us mere mortals. DD

[ford38v8]

Originally Posted by V8COOPMAN

You DID read that correctly when you look at the 6.00 tires and the 40 17270 turtle. I take that to relate to MODEL 40 ('33&'34). If you look a little further down at the 6.00 tires and the 68 17270 turtle (which SOMEHOW seems to relate to MODEL 68...1936 model year AND LATER), the chart indicates a 20-tooth. There's obviously a part of this puzzle that is escaping us mere mortals. DD

Well, I guess I'll put my foot in my mouth now. I believe rockfla got it right. The prefix of the part signifies the period of time the part was first made available, and is not limited to any certain year by the fact that the prefix corresponded to a year model. This was a standard practice that held true for many different parts, although not exclusively as we all know, never say never, never say always.

Turtle housings were made specifically for the gear enclosed, with that tooth count number boldly displayed on the turtle's shell. Each housing was different in the respect to the depth of it's gear's centerline, in order to mate correctly with the drive gear, which were all the same. This is the way it was done by Ford back in the day. Today, however, repop gears are made and jury rigged into whatever turtle is available, by those who cannot find or will not pay for the real McCoy. This practice of mix & match confounds and confuses the new generation of Fordophiles, and apparently some of the old geezer generation as well. There, I said it and I'll shut up now.

[V8COOPMAN]

Ya know....sometimes when ya (I) think ya know a little bit about something you've been messin' with (these old used cars) seemingly forever, it takes another (possibly even more-seasoned) old geezer to step-in and slap ya (ME) around just enough to remind oneself that oneself has either forgotten some really pertinent info, or worse yet, that the person being reminded is likely (at least THIS time) confused and FULL OF IT! In retrospect, Alan (ford38v8) is absolutely correct in every statement he has made just above. Thanks for keeping me straight and somewhat honest, Alan! Apparently, all of this "accumulated mileage" can occasionally cause a severe miss in performance. DD

[Tinker]

....


.

[rockfla]

Once again, thanks for all the help and knowledge. I learned a valuable lesson in respect of "don't trust what you are seeing when you can "only" see about 1/4 of what you're looking at!" Low and behold, 1/2 of the drive shaft worm gear is "toast"!!! SO it's looking like a "nice" future project at some point to drop the rear and fix!!! Thanks again for ALL who helped me "LEARN".


As an aside......anyone have a speculation as to what might cause this kind of damage??? The "mushed" turtle gear still spins nicely???

[Mart]

What is that thing (or substance) wedged in the top of the opening in picture 1?

Glad you opened it up and found the source of the problem. Good thing is, the worm is standard across all passenger cars so should be easily found.

Mart.

[Kube]

[QUOTE=rockfla;1886613]Once again, thanks for all the help and knowledge. I learned a valuable lesson in respect of "don't trust what you are seeing when you can "only" see about 1/4 of what you're looking at!" Low and behold, 1/2 of the drive shaft worm gear is "toast"!!! SO it's looking like a "nice" future project at some point to drop the rear and fix!!! Thanks again for ALL who helped me "LEARN".


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