My car has had the rear gears swapped at some point. I just crawled under it today and found out that i have a 3.42 posi in it. My question is my speedo is off about 10mph and i need a new speedo gear. Is there a way to tell what gears i had in it before so that i know what drive gear i have to get the correct driven gear for the speedo?

 

1988 IROC with a 305 TPI and A4 transmission came with 2.73 gears. If it had the G92 option code, it came with 3.23 gears.

 

G92 was just the code for a performance axle right? I just checked my codes in the center console and i dont have code G92. I have code G80 which im going to assume is just the code for the normal axle. Anyways does that tell me what drive gear i have? I was on another website and they didnt list 2.73s. Here is the website.

http://www.transmissioncenter.net/sp...n_______va.htm

Is there another better one to use? I just need my speedo to be accurate again.

 

What other codes that start with G do you have? I'm guessing there is GU2 which is 2.73 gears.

 

Id have to double check this afternoon but i seem to remember seeing that one as well. Its fairly safe to assume that this car had 2.73s in it. Does that mean that it has an 18 tooth drive gear? And if so do i need to change both my drive gear and driven gear to get my speedo to read correctly for the 3.42s?

 

http://www.4lo.com/calc/geartable.htm

see what speedo gears are in it now and go from there, let me know if this helps. it about the middle of the page where it starts detailing speedo calibration.

 

G80 = posi

My car came with the performance diff, 3.27 geared 9 bolt and doesn't have the G92 RPO code.

 

Ok well im still not sure about some things. I kno that my car came with 2.73s originally. Its now got 3.42s in it. Do we know what size drive gear it has so i can match it up with the corresponding driven gear or do i have to replace both to get the speedo to read correctly.

 

bump