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Is this a correct older A727 speedometer gear?

AR67GTX

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Since I installed a 3.55 rear my speedometer was way off with a 31 tooth gear. Ordered a 34 tooth gear (I have 15 inch tires/wheels) and was in the process of swapping them out when I noticed how much thicker the teeth are on the 34 tooth gear. Thought I better check before I try to install it.

Does this look like a good gear for an older Toqueflite? Or is it maybe a gear for a newer Torqueflite with different drive gear? This is a 68 transmission.

IMG_4598_zpskf7nurqf.jpg


Thanks
 
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The new gear is completely different
I have a whole box full of gears down at the shop- can check Monday if you do not get a better answer by then
 
Thanks - here are some better photos

IMG_4600_zpsptwleus4.jpg

IMG_4599_zpsbnv0jwki.jpg
 
Maybe that fits 518’s? When I had to buy one, the newest were early 70’s!
 
Correct me if I am wrong, but isn't the metal housing designed to be offset for the different ratios? If you look at the speedo cable end there should be 4 hash marks one of them needs to line up with mark on the tailshaft housing, I thought there might be a chart or numerics stamped onto housing that reflects the number of teeth that is on the gear you line up the hash marks and bolt it down
 
Ski is right, why not try the new gear w/o the adapter just by hand to see if teeth hit the output shaft correctly? Just a thought.
 
Correct me if I am wrong, but isn't the metal housing designed to be offset for the different ratios? If you look at the speedo cable end there should be 4 hash marks one of them needs to line up with mark on the tailshaft housing, I thought there might be a chart or numerics stamped onto housing that reflects the number of teeth that is on the gear you line up the hash marks and bolt it down

Yes - the housing is so marked and has to be clocked to the appropriate position to hit the spiral drive gear on the output.
 
Ski is right, why not try the new gear w/o the adapter just by hand to see if teeth hit the output shaft correctly? Just a thought.

I might try this - I have the car under a lift jacked up in the rear and I can barely scoot under it on a piece of cardboard so not sure if I can get a good view of the inside.

Thanks
 
Well, if lewtot says orange, you might have the wrong one.
 
should be an orange 35 tooth.

The charts kept showing either a 33 or 34 tooth. Pretty sure a 33 tooth wouldn't be enough correction because with my phone on a GPS apt it was reading about 38 when the speedo was clocking about 44 or 45. My speedometer was making noise and still jumping a little and I've had to pull it out and send it off (again) for rebuilding - which is another sad story. I have 215/75-15 tires which are pretty tall. It's conceivable I may have to go to a 35 tooth but I decided to try a 34 first. I may just be adding to my boxes of old Mopar parts in the attic and under the work bench.

Thanks
 
pretty sure factory 3.54 geared 15" wheels were 35 orange. 3.55 14" , red 36. my 69 r/t 3.23 14" wheels came with 32. all I can say is just try the 34 and see what you get. if you end up needing something other than 34 it's no big deal to change. the 215 tire should be about 27.5" tall. a g70x15 polyglas was about 27.75" tall.
 
pretty sure factory 3.54 geared 15" wheels were 35 orange. 3.55 14" , red 36. my 69 r/t 3.23 14" wheels came with 32. all I can say is just try the 34 and see what you get. if you end up needing something other than 34 it's no big deal to change. the 215 tire should be about 27.5" tall. a g70x15 polyglas was about 27.75" tall.

Which brings up an interesting point regarding radials and correcting speedometer readings. Yes, the 215/75 tire is supposed to be around 27.5 inch tall but with the car on the ground, if I measure from the ground to the center of the wheel cap I measure a rolling radius of around 13.25 inches (26.5" dia) due to the soft sidewalls on radials. I figure at high speed some of that soft bulge may come out due to centrifugal force and increased heat/pressure - but rolling around town at 45 - 50 mph - probably not.
 
Which brings up an interesting point regarding radials and correcting speedometer readings. Yes, the 215/75 tire is supposed to be around 27.5 inch tall but with the car on the ground, if I measure from the ground to the center of the wheel cap I measure a rolling radius of around 13.25 inches (26.5" dia) due to the soft sidewalls on radials. I figure at high speed some of that soft bulge may come out due to centrifugal force and increased heat/pressure - but rolling around town at 45 - 50 mph - probably not.
Now you’re just nitpicking!lol
 
Which brings up an interesting point regarding radials and correcting speedometer readings. Yes, the 215/75 tire is supposed to be around 27.5 inch tall but with the car on the ground, if I measure from the ground to the center of the wheel cap I measure a rolling radius of around 13.25 inches (26.5" dia) due to the soft sidewalls on radials. I figure at high speed some of that soft bulge may come out due to centrifugal force and increased heat/pressure - but rolling around town at 45 - 50 mph - probably not.
you have to measure tire roll out. the tire has to roll the full circumference; measuring ride height is incorrect.
 
Well anyway - back to the thick toothed speedometer gear question? Anyone have a used 34 tooth gear for comparison?
 
Ski is right, why not try the new gear w/o the adapter just by hand to see if teeth hit the output shaft correctly? Just a thought.

I tried this today but between laying on the floor with my head barely clearing the exhaust pipes, trying to hold the gear in the opening with one hand, positioning the light with the other and trying to position my head and my bifocals so I could see - couldn't do it. So I went ahead and stuck the adaptor and gear in and indexed it for the tooth count and installed the clamp. Sticking a square head drive in the cable socket and it wouldn't turn so it's engaged in the output shaft threads.

Probably be May or June before my instrument panel and rebuilt speedometer (3rd time) is back and I can try it out.
 
I tried this today but between laying on the floor with my head barely clearing the exhaust pipes, trying to hold the gear in the opening with one hand, positioning the light with the other and trying to position my head and my bifocals so I could see - couldn't do it. So I went ahead and stuck the adaptor and gear in and indexed it for the tooth count and installed the clamp. Sticking a square head drive in the cable socket and it wouldn't turn so it's engaged in the output shaft threads.

Probably be May or June before my instrument panel and rebuilt speedometer (3rd time) is back and I can try it out.
Just gotta luv those bi-focals!!!!!
 
Just as a follow up in case anyone needs a reference on a speedometer gear.

Well the speedo problem appears to have been a bad cable and for some reason my in-ability to bench test it with a drill and another cable. A 3rd cable (30 inch worked perfect) lubed with Tri-Flow (really slippery stuff) seems to have been the cure.

The 34 tooth gear worked pretty well for 215/75-15 tires. At 50 mph I was reading 51 mph on my phone GPS app so about 1 to 1-1/2 mph slow at this point - better than my wife's Highlander. But I've been thinking of switching to 215/70 tires and if I do I will probably need to switch to the 35 tooth gear.
 
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