Speedometer Gear Question (Again) - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 19 (permalink) Old Feb 14th, 03, 07:04 AM Thread Starter
Senior Tech
 
Join Date: Aug 2002
Location: Duncansville, Pa.
Posts: 259
I recently made some posts concerning my speedometer cable and you guys helped me figure that one out. My cable is new, the speedometer in the dash works, now here's the continuing saga of my speedometer woes. I was told to get a larger green 22 tooth driven gear and it still doesn't work. The driven gear I just bought just barely fits into the hole, so I can't possibly go any bigger. Seems like the drive gear may need to be moved a little to catch the driven gear. (Is this possible?). It's not off much, but nevertheless may need moved very slightly. The drive gear looks to set toward the rear of the car a wee bit too much. I can look into the drive gear hole with a flashlight and mirror and see the steel drive gear. (Looks to be new). Any suggestions without taking the tailshaft off? Thanks! Bill (redlines4us)
redlines4us is offline  
Sponsored Links
Advertisement
 
post #2 of 19 (permalink) Old Feb 14th, 03, 08:17 AM
Senior Tech
 
Join Date: Sep 2001
Location: Elizabethtown, PA
Posts: 980
Send a message via AIM to Spames
I don't think you have a mechanical problem. There are many combinations of speedo gears, and in order to get the correct combo, you need to know what gear is inside your transmission. You might have gotten an outside gear that is incompatible with the inside gear you already have.

------------------
68 Coupe, 350 4-speed
Jim's Camaro Corner
Spames is offline  
post #3 of 19 (permalink) Old Feb 14th, 03, 10:23 AM
Senior Tech
 
Join Date: May 2001
Location: Lancaster, PA
Posts: 122
redlines4us'

I've attached links to three other threads that discuss this type of speedo issue.
https://www.camaros.net/forum/Forum9/HTML/007184.html
https://www.camaros.net/forum/Forum9/HTML/007257.html
https://www.camaros.net/forum/Forum16/HTML/000459.html

Also, the drive gear inside the tranny is moveable but not without removing the tailshaft cover, and since yours is steel using a gear puller to remove it. You could than heat the steel gear with a torch and slide it on to a slightly different location. Maybe you want to consider the smaller driven gear with a reducer fabed at a speedometer shop to get the correct readout.

Good luck.

Doug

------------------
Doug

'69 SS clone 350/M-20
'65 327/275 Corvette Coupe (regrettably sold years ago)



[This message has been edited by GDV350SS (edited 02-14-2003).]
GDV350SS is offline  
 
post #4 of 19 (permalink) Old Feb 14th, 03, 10:42 AM
Senior Tech
Jim
 
Join Date: Nov 2002
Location: Ontario & Oceanside CA.
Posts: 1,323
First of all, does the cable turn when the drive wheels are turning? Remove the cable from the back of the dash and drive the car or jack it up (careful if you have posi) and observe the cable. If it's turning, your trouble is in the speedo head. A test for the speedo head is to remove the cable at the tranny and use a drill in REVERSE and observe the speedo. At least this way you can isolate the problem and deal with it. The drive gear should be directly behind the hole for the driven gear. I've never seen a steel one move, but I have seen them incorrectly installed. The plastic gears are held on the shaft by a metal clip. Sometimes these clips will pop out if the cable seizes, and the speedo drive gear cant turn the cable. In either case, you will have to remove the tail housing to fix it. While you are under the car, count the teeth of the drive gear and write it down. If you need a chart for driven gears and a formula for figureing out which one you need and GM part numbers, e-mail me and I'll send you one.
Jim
Jim

------------------
69 Z/28 RS frame off rotisserie restoration.
Jim & Linda's 69 Z/RS
GMJim is offline  
post #5 of 19 (permalink) Old Feb 15th, 03, 02:12 AM Thread Starter
Senior Tech
 
Join Date: Aug 2002
Location: Duncansville, Pa.
Posts: 259
I have used a drill motor and have determined that the speedometer in the dash does work. I have 15" tires and 3:73 gears. I was told to use GM Part #3860345 - 22 tooth green gear. It's the largest gear that will fit through the hole and it still doesn't mesh up with the drive gear. I'll try to count the teeth on the drive gear, but if I can't put any larger driven gear through the hole in the tailshaft, that suggests to me that the drive gear may be out of place. I'm not concerned right now with the accuracy of the speedometer, just getting the gears to work and mesh is my main concern. Bill



[This message has been edited by redlines4us (edited 02-15-2003).]
redlines4us is offline  
post #6 of 19 (permalink) Old Feb 15th, 03, 02:14 AM Thread Starter
Senior Tech
 
Join Date: Aug 2002
Location: Duncansville, Pa.
Posts: 259
After I installed the new 22 tooth driven gear, (With the speedometer cable unhooked at the tailshaft)I took a small tip screwdriver and placed it in the square hole in the end of the gear and is spins freely and does not mesh with the drive gear. I then took out the driven gear fitting (the fitting with the "O" ring) and put the driven gear in the hole by hand and slightly moved it to the side and it seemed to mesh that way. That's why I believe the drive gear may need to be moved slightly. Any suggestions? Thanks! Bill




[This message has been edited by redlines4us (edited 02-15-2003).]
redlines4us is offline  
post #7 of 19 (permalink) Old Feb 15th, 03, 03:38 AM
Gold Lifetime Member
Paul
 
PDQUICK's Avatar
 
Join Date: Oct 2001
Location: Londonderry, NH
Posts: 1,010
redlines,

Has the transmission been out for a rebuild since the last time you saw the spedometer work? Was the tail housing or main shaft swapped out? The flat area that the drive gear presses over on the tailshaft is about an inch long. This gear can definitely be misaligned with the hole in the tail housing. You might have to remove the tail housing and move the gear a little bit to get it back in alignment. Make sure that you mark the shaft with the desired gear position before you pull the housing!

[This message has been edited by PDQUICK (edited 02-15-2003).]
PDQUICK is offline  
post #8 of 19 (permalink) Old Feb 15th, 03, 04:27 AM Thread Starter
Senior Tech
 
Join Date: Aug 2002
Location: Duncansville, Pa.
Posts: 259
Transmission is supposedly rebuilt. I never did have the speedo working.
1970 Muncie - M20 Wide Ratio 2 Groove Input Shaft
Main Case Casting #3925660
Tail Housing Casting #3857584
redlines4us is offline  
post #9 of 19 (permalink) Old Feb 15th, 03, 08:43 AM
Gold Lifetime Member
Paul
 
PDQUICK's Avatar
 
Join Date: Oct 2001
Location: Londonderry, NH
Posts: 1,010
I might be wrong, and maybe some of the other guys can correct me on this, but I seem to remember rebuilding some of the later '70 up Muncie's and I thought that they had plastic speedo drive gears held on to the tailshaft with a metal clip like the automatics. On these models you could put the speedo gear/clip in backwards and it would be out of alignment with the driven gear.

Anybody else recall this being the case??

Paul D.
PDQUICK is offline  
post #10 of 19 (permalink) Old Feb 15th, 03, 06:12 PM
Senior Tech
 
Join Date: May 2001
Location: Lancaster, PA
Posts: 122
PDQUICK,

Some of the a Muncies did use the plastic gear with a clip and indeed it would be possible to flip the clip and mis-align it. Redlines4us states in his first post that he can see a steel gear inside. This still leads me to believe that the steel gear was placed on the tailshaft slightly out of position since there is no positive stop for the gear on the shaft. I believe he will have to relocate the gear on the shaft. I can't think of an easier way than removing the rear cover section and pulling the gear and then heating and sliding it back on in the correct position. I bet it's only about a 1/4" off now, but that's enough to cause the trouble he's having. What do you think?

Doug
GDV350SS is offline  
post #11 of 19 (permalink) Old Feb 15th, 03, 10:58 PM
 
Join Date: Sep 2002
Posts: 10
I'm not sure if this implies to your transmission but when I did my 700R4 I had the same problem. I was told by my local tranny shop that the speedometer gear would need to match with the gear on the imput shaft. Depending on the person who rebuilt your tranny, there may be more than one shaft for your tranny (it all depends on what tranny you have). I know that the 700R4 has about 3 shafts that I know, it depends on the car that you have or your needs (I beleive that the corvette has the short one). If your tranny mechanic had to replace it, the other shafts are similar to each other and could be easily confused. One of the shafts is very close to being the same as the other, I know that the location of one of the shafts, the gear is off-set. The only other reason could be a wrong choice of speedo-gears. Well, I hope you fix the problem and it was of some help.

------------------
Rene
'67 RS/SS Camaro, 350, 700R4.

[This message has been edited by crene67ss (edited 02-16-2003).]
crene67ss is offline  
post #12 of 19 (permalink) Old Feb 16th, 03, 02:30 AM
Gold Lifetime Member
Paul
 
PDQUICK's Avatar
 
Join Date: Oct 2001
Location: Londonderry, NH
Posts: 1,010
Yeah GDV I agree,
I suggested the same thing a couple of posts back up the list.

Redlines,

I can't think of an easier way to do this either. (removing the tail housing!)

Good Luck!

Paul D.
PDQUICK is offline  
post #13 of 19 (permalink) Old Feb 16th, 03, 03:02 AM
Senior Tech
Jim
 
Join Date: Nov 2002
Location: Ontario & Oceanside CA.
Posts: 1,323
redlines

Sounds like the drive gear is not properly located. I would remove the tailshaft housing and if the gear is too far forward, I would use the reverse gear as a slide hammer. The speedo gear will move easily, so you won't have to bash the gears up. Just tap it a little at a time. If the gear is too far back, you can usually move it with a hammer and a small block of wood. I have a piece of pipe that I slide on the shaft to do this and don't really need a hammer. In some extreme situations I would use a propane torch to warm up the gear to move it, but I've only had to do this once or twice that I can remember. If you don't know the procedure to remove a tailshaft housing from a Muncie, ask. It isn't difficult, but it's one of those things that go a lot easier if you've done it before.
Jim

------------------
69 Z/28 RS frame off rotisserie restoration.
Jim & Linda's 69 Z/RS
GMJim is offline  
post #14 of 19 (permalink) Old Feb 16th, 03, 05:05 AM Thread Starter
Senior Tech
 
Join Date: Aug 2002
Location: Duncansville, Pa.
Posts: 259
Thanks guys. I'm convinced that the speedo drive gear sits too far back toward the rear of the tailshaft to contact the driven gear. It's seems to be only about 1/8" off. I guess removing the tailshaft housing is the only way to go. I'll keep you posted. Thanks again! Bill

redlines4us is offline  
post #15 of 19 (permalink) Old Feb 16th, 03, 05:10 AM Thread Starter
Senior Tech
 
Join Date: Aug 2002
Location: Duncansville, Pa.
Posts: 259
GMJim, I have emailed you directly! Bill

[This message has been edited by redlines4us (edited 02-16-2003).]
redlines4us is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome