727 Trans Speedometer Gear

[Mr. Belvedere II]

It could be a optical delusion
View attachment 414008

I'm leaning towards illusion as well, the more I look and compare the edge on teeth lengths they all seem uniform. And I would think based on how they are supposed to mesh that if they were to be stripped then the damage would be much more obvious . I think they have never actually contacted the other pinion.

 

[Mr. Belvedere II]

With the gear installed, try removing the speedo cable from the gear and turn the gear with a small screw driver. It should not turn. If that is correct try a battery drill on the speedo cable, have someone watching the dash and make sure the speedo needle moves smoothly as you increase the speed of the drill. If that is correct make sure the speedo cable is engaging the speedo gear fully, and in to the speedometer fully.

Good call on trying to turn it while installed it's in the housing! If you read my earlier post you will see I have made certain all works from the gear to the speedometer!

 

[AMX364]

Is the year of the transmission different then the speedometer gear, now? It might need a different gear. 66 and up is different from older

 

[Mr. Belvedere II]

Is the year of the transmission different then the speedometer gear, now? It might need a different gear. 66 and up is different from older

The transmission is a 727 torqueflight "Sizzler" from TCI. So aftermarket. Bought it few years ago

 

[AMX364]

And the car?(speedometer gear)

 

[Mr. Belvedere II]

And the car?(speedometer gear)

Oh, it's a 67 Belevedere with the yellow 30 gear!

 

[Paul_G]

Good call on trying to turn it while installed it's in the housing! If you read my earlier post you will see I have made certain all works from the gear to the speedometer!

Are you done troubleshooting the problem then? What did it turn out to be?

 

[Mr. Belvedere II]

No, I put it all back together with the housing lined up according to how many teeth the gear had and I still have no active speedo. It seems to me the gear isn't contacting the drive pinion. Don't know what else the problem would be. It isn't all that complex sooooooo. I'll be giving TCI a call this week to see what they have to say for themselves.

 

[jim ritchie]

Optical allusion or not it looks like its stripped and heat burn at 3,oclock position,could only tell if picture was taken straight on!GOOD LUCK,easy fix if it's only nylon gear.

 

[AMX364]

Here are the pinons that came as options.FOR 65 OLDER
16 teeth brown
17 teeth orange
18 " Dark purple
19 " dark blue
20 " green
21 " Gray
http://www.tciauto.com/tc/speedometer-gear-calculator
TCI claims gear on outputshaft is made (13 tooth)on shaft. Pics clearly show a pinon gear inside trans. I have not found newer pinon numbers and colors. It could be the (current)pinon gear is for more aggressive rear gears.

 

[66Satellite47]

Be sure actually count the number of teeth. I have some that the number of teeth is not the same as the number stamped on the plastic gear. No idea why. BTW color coding does seem to vary with different years. Another silly question but are you sure you had the index mark for the tooth range matched up with the tailshaft housing. There's a stamping mark on each & don't line up with the numbers on the speedo gear housing. Just a question.

 

[Mr. Belvedere II]

Be sure actually count the number of teeth. I have some that the number of teeth is not the same as the number stamped on the plastic gear. No idea why. BTW color coding does seem to vary with different years. Another silly question but are you sure you had the index mark for the tooth range matched up with the tailshaft housing. There's a stamping mark on each & don't line up with the numbers on the speedo gear housing. Just a question.

Yes I did count just to be sure that was what that number on the gear meant cuz I wasn't sure myself! But yes it did come up to 30. As far as the housing is concerned, I placed the 26-31 range numbers in the six o'clock position which placed the gear in the highest upward position and locked it in.

 

[Mr. Belvedere II]

Be sure actually count the number of teeth. I have some that the number of teeth is not the same as the number stamped on the plastic gear. No idea why. BTW color coding does seem to vary with different years. Another silly question but are you sure you had the index mark for the tooth range matched up with the tailshaft housing. There's a stamping mark on each & don't line up with the numbers on the speedo gear housing. Just a question.

I just can't imagine what else I'm missing, I'll be calling TCI tomorrow

 

[mopar 3 B]

Am I missing something or is the alignment nub that is supposed to be at the bottom of the hole of the tail shaft not there? The gear housing and that nub needs to line up for the gear being used.

 

[Mr. Belvedere II]

Am I missing something or is the alignment nub that is supposed to be at the bottom of the hole of the tail shaft not there? The gear housing and that nub needs to line up for the gear being used.

If you are referring to this pic below, it is not if my trans, I only used it as an example of the gear.

 

[66Satellite47]

I just can't imagine what else I'm missing, I'll be calling TCI tomorrow

There may some difference in the adapters year to year & the associated plastic gears. I need to search through my parts collection to see if I can see any difference. My adapter doesn't seem to fit quite right into my aftermarket trans which of course didn't come with the speedo setup which I kept from the previous trans. More investigation is needed.

 

[Paul_G]

Next time you get a chance to remove the housing stick your finger up in the trans and see if the plastic gear spins free. It should not

Then maybe raise the axle off the ground and turn the drive shaft and make sure the plastic gear in the trans turns with the drive shaft

Only other thing it might be is the speedo cable not engaging fully at the trans adapter or the speedo. Have you pulled out the speedo cable and inspected it?

 

[Mr. Belvedere II]

Next time you get a chance to remove the housing stick your finger up in the trans and see if the plastic gear spins free. It should not

Then maybe raise the axle off the ground and turn the drive shaft and make sure the plastic gear in the trans turns with the drive shaft

Only other thing it might be is the speedo cable not engaging fully at the trans adapter or the speedo. Have you pulled out the speedo cable and inspected it?

I know that spinning gear while its on the cable will make the needle sweep on the dash. I'll check it out next time I'm under there! Thanks for the tips!

 

[RT K_line]

If I remember the drive portion of the set up is part of the shaft and not a separate gear on the shaft. What gear is in the diff?

 

[oldbee]

You guys had me doubting my memory also, got the book out.