My speedo died on the way home. Before it died it read perfectly. When I got home I started to replace the components. I thought that it might be the cable, so I replaced it. That wasn't it. Next, I pulled the housing holding the speedo gear. I was checking it out to see if that was mutalated or broken, or something. There was nothing wrong with that so I did not replace it. I then was just looking around and looked inside the tailshaft and saw that the speedo gear on the output shaft was moving around. It turned out that the gear was cracked and that is why it was not latched onto the output shaft. I then took off the tailshaft and everything assosiated with it, then replaced the gear. It is the same one that I took off.
After I put it all back together, I took it for a drive and my parents were in their car. It should read correctly because the cable and the gear that I replaced were identical to the ones I took off, right?

WRONG, it does not read right. It's about 15 MPH too slow. For example, going 45 MPH the speedo read 30 MPH.

Is there something in the speedometer itself that needs to be adjusted before you put the cable back in?

My dad was thinking that the speedo might be set at negative 15 MPH and not zero. It also gives a reading between the trip button and the dot that means zero MPH. I was going about 5 MPH or more(estimated) before it got to zero.

I also have 3.23 rear gears, a 15 tooth green gear on the output shaft, and I believe a 38 or 36 blue speedo gear(I can't remember off the top of my head and I didn't write it down.)
My transmission was also replaced in March, and it read just fine.

I know for a fact that the gear I put on is set right on the output shaft. Is there a possibility that the speedo gear is not set right?

I have not been able to talk to a mechanic or the parts guy(who is a tranny guy) because I did not get home until after they closed.

Thanks,
Jesse



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85 Z28, 305 TPI A4
pretty stock with a few toys
15.2@91mph
http://photos.yahoo.com/j_hougnon

http://screamindeamin.cz28.com/images/jesse/

 

check the faq for more info...are you SURE you replaced the gear w/ one exactly like the one you had?

 

yup, i am sure. i checked that too.

thanks anyways.

 

i can tell you that the combo you just put in is wrong i swapped 2.73 for a 3.27 rear and the only thing i changed was the driven gear the drive gear for 3.23 and 3.27 is a red 17 tooth gear the 45 tooth light blue driven gear match up perfectly being .4 difference in our rear i would say that with you being that much off the drive geaar is the problem if it was a driven gear it wouldn't make such a large difference

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87 trans am 350 L98 aluminum heads,LT4 hot cam,slp runners,headers,y-pipe,edelbrock base,hi flo cat,air foil,ported plenum,t-5 tranny w/centerforce clutch and a 3.27 9bolt,ads strip chip,relocated iat sensor,hollowed maf

14.10@97mph w/2.01 60' LOOKING TO TRADE?ANYONE

 

Well, I replaced the gear with the exact one that I had taken out. The problem was thet the speedo was set at negative 15 MPH, so I just reset the needle for now. When I get enough money, I will construct a new dash with Autometer guages. Oh yeah, Vader replied to one of my other posts and said that the speedo misadjusted itself.

Thanks,
Jesse