REPLACING SPEEDO GEAR IN 2004R

[crucial118]

Wasup? Having a problem, as the title insists. I just put in a 3.73 rear in my 86 cutty with the 2004r trans and my speedo is way off. My tire size is approx 26". I tried going to all the gear calculators and they all ask for the # teeth on the drive or driven gears and I have no idea for either. I tried pulling the speedo gear out to count the teeth, but it doesn't come out like the th350s do. Looks like you have to take the pan off and go inside(I hope not!).

If anyones done this gear change before, help me please. What driven gear did you change to and how did you change it? I had 2.56s in it before the swap. Thanx.

 

[DRIVEN]

Here you go:
http://www.transmissioncenter.net/speed ... ____va.htm
About 1/3 of the way down the page.

 

[crucial118]

Yeah, I've been there also and it asks for the drive gear teeth number. I don't know what the stock drive gear teeth # is for a stock 2004r with 2.56 gears and a 26 in tire. If so that would give me a base to start with, but I don't know where to start. I don't know the drive or driven teeth #.

 

[DRIVEN]

Yes, you have drop the pan to replace it. This tread isn't really related but does show where and how:
http://www.oldspower.com/vb/showthread.php?t=37965
The drive gears are color coded and if you pull the driven gear (where the cable threads in) out the side, you should be able to look inside to see which one you have without actually removing the pan or governor. The color chart is in the first link I posted. If you find that you have to replace drive gear it might be a good opportunity to upgrade to a governor with higher shift points. Hope that helps.

 

[DRIVEN]

Using the supplied drive gear/driven gear chart it looks like you need green/green.

But a green/yellow or orange/white would be close.

 

[beermonkey9417]

thats funny, im doing the same thing: viewtopic.php?f=7&t=8386&start=360 but im also rebuilding the whole damn trans too.

 

[crucial118]

Thanks Driven, for the info. I pulled my old 2004r's driven gear and it had 28 teeth. With 28 tooth driven and 2.56 rear gears, according to another calculator, the drive gear should be around 12 or 13 tooth. And according to that calculator, with 3.73 rear and 13 drive, I need a 41 tooth driven gear. The rebuilt trans I put in it was from a 305 Monte, so it should've had tall rear gears also. So I just order 2 from Summit(31 tooth and 37 tooth). They were only $15 each, so I'll try both and 1 should, at least, get me close.