Ok I think I have the speedo gears figured out for my 88 WC T-5 and 3.42 gears where I oribinally had 3.08 gears (been that way for 4 years!). So, now the problem is how do I change the things.

I know the output shaft has the red gear on it b/c I remember seeing it when I re-built my tranny but where is the other gear? Can I just pull the rear seal off the tranny and access the gear from there?

Also, I know there are 2 chips in the computer and one is the one you change out for a performance chip but I thought the other one had the gear ratio information in it. I remember faintly when I ordered a new computer 3-4 years ago, the guy at the dealer said the small chip is ordered depending on the gear ratio I haveso I told him 3.08 at the time....does that make since? Would that chip control the VSS?

thanks guys!

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1988 TA 300+hp 350 w/ TBI and Holley TB unit, Holley projection intake,
WC T-5, 3.42 gears w/ Auburn posi. MSD 6A, edelbrock TES headers, dynomax 3" cat and cat-back system, ACCEL coil, polyurethane bushings all around, aluminum driveshaft, Mr. Gasket open air cleaner.

1993 S-10 w/ 4.3L V6 TBI, slightly bigger cam, Mild polish job and 3 angle valve job on heads, Edlebrock TES headers, Dynomax cat back, MSD 6A, ADS chip

2000 Kawasaki KX 125

 

I honestly have never heard of that extra chip in the computer but I can tell you that from my experience in changing speedo gears that you have to take the whole extension housing off of the transmission to access the speedo gear inside the tranny. I did this on my IROC when I swapped in 3.73 gears for the stock 3.08's. I thought I wouldnt have to take the transmission out but when I went to get the extension housing back on, it wouldnt sit flush and i couldnt get a good seal....so i removed the tranny by the 4 main bolts holding the tranny in, and it was alot easier to get the extension housing back on while the tranny was out of the car. If you want more info on this, post more questions. I can assure you this will take you 1 full day of work in the driveway and it isnt fun but you will have your speedometer reading correctly afterwards.

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88 Iroc 305 TPI 5 speed
Performance Resource Chip, Flowmaster American Thunder cat back exhaust, B&M Ripper shifter, MSD coil, TB bypass, TPIS MAT relocation kit , TPIS 170* t-stat, Richmond 3.73 gears, March Power & Amp pullies Home made Ram Air
Best et: 14.338
Best mph: 96.97
Best 60': 2.106

[URL=http://hometown.aol.com/famioso15/johnnyiroc.html]

 

There are 2 gears located in the trans for the spedo. One is a drive gear and the other is a driven gear which resides directly behind the VSS.
You may be able to get by with just changing the driven gear in the trans. In which case you won't have to remove the rear tailshaft housing. The only reason you would need to do that is if you needed to change the drive gear.
Never seen an F-body with 2 chips in the ECM. There is only one and the only thing your ECM has to do with your transmission is control the torque converter clutch, it does not control the VSS. There is no information stored in the chip for rear end ratios.

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1994 LT1 Corvette Convertible

 

I have a similar question. I have a t5 with the electrical speedo output,but my car has a cable driven speedo. What do I need to do to make my speedo work. How do I hook a mechanical speedo up to the t5 with the electrical type plug. Also what speedo gear/gears do I need my car has 3.73 rearend. Thank you very much for any help Kevin

 

Kevin, you can swap the cable speedo unit for the electric speedo unit easily. Also you'll need a 7 tooth drive gear and a 21 tooth driven gear for a 3.73 rear end. Didnt I mention this before to you?


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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

Yea, Thank you. I am just not totally clear on the speedo cable. DO I need a new houseing for the trans or what? Thanks for your help and sorry for the confusion. I just want to get everything right before I do the swap. Kevin

 

Nope, all you need is the new unit. Its located on the driver's side rear end of the trans. Just remove the one thats there, and put in your unit, and thats it.

 

Ok thank you!

 

dont u also have to consider the rear tire size for speedo gears?


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350, Comp 262, Edelbrock Performer intake 600 cfm carb and exhaust, headers
-JVC, Eclipse, Pioneer, MTX, Phoenix Gold, Planet Audio

 

Only if you changed the size.