21 tooth speedo gear

doug93sc

Registered User
I removed the factory speedo gear (which was working fine) because I have 3.27's and lower profile tires and installed a 21 tooth gear in its place so the speedo would be more accurate. The problem I am having is it will work for about 1 minute then the speedo will stop working, well I took it out last night and about 5 of the teeth were bent. I straightened them out re installed them and it did the same thing this morning, my question is has anyone else had this problem? I assume it is because the teeth are not as thick it ends up bending them down I had the same 21 tooth gear in my 93 for about 15 thousand miles and it had no problems at all. Do you guys have any suggestions?

The only major difference between the 92 I put the gear in and the 93 I had it is that the 92 is a 5-speed and the 93 is an auto, I thought they used the same speedo gears though.
 
hmm, my car had this problem when i got it (the gear with bent teeth), but i put a new gear in and haven't had any problems since.

Perhaps when you installed the gear you put too much load on it before it got used to being there (i.e. accelerating too fast)? I don't know if it makes much sense, but its all i can come up with. Also, if thats the case, once the teeth have been bent, bending them back probably won't work because the teeth have already been weakened.
 
gspacerant said:
hmm, my car had this problem when i got it (the gear with bent teeth), but i put a new gear in and haven't had any problems since.

Perhaps when you installed the gear you put too much load on it before it got used to being there (i.e. accelerating too fast)? I don't know if it makes much sense, but its all i can come up with. Also, if thats the case, once the teeth have been bent, bending them back probably won't work because the teeth have already been weakened.

Well I really didnt accelerate to fast, I would think that just getting up to about 10 MPH it would seat properly.
 
I think the manual trans uses a different speedo gear than the automatic. If I recall correctly the speedo gear calculator in the FAQ section has the part numbers listed for the gears.

Here you go. Near the bottom of the page the P/N's are listed.
Speedo Gears
 
Kevin Varnes said:
I think the manual trans uses a different speedo gear than the automatic. If I recall correctly the speedo gear calculator in the FAQ section has the part numbers listed for the gears.

Here you go. Near the bottom of the page the P/N's are listed.
Speedo Gears

Thanks Kevin for pointing that out....I need to learn how to scroll down!!

Off to the Dealer I go then....
 
Just to let you all know I was just at the local Dealer and bought a 21 tooth speedo gear for my 5 speed and it only cost $8.73 which included tax!! Of course they had to order it but it will be in tomorrow. On a side note I think when I bought the one for my auto a few years ago it was about $14.00.
 
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