I did the swap months ago and I never got to putting in the correct speedometer gears. I have the yellow and the grey one. I've read conflicting responses, but do I need to replace both in there, or will one do the trick?

Thanks.

 

what gear's are you talking about? Since you are talking about colors I'm assuming speedo gears, so I'd say you need to change it to bring the speedo back into calibration.

Other than that, if you're talking about the rear end gears then you need to replace both the ring and pinion at the same time due to the fact that they are a matched set

 

Dumb!!!! Sorry, yes I meant speedo gears. So I need both of them? Is there an easy way to get to them?

Is there a writeup for an install?

 

I'm not really sure what you mean by both. What I can tell you is that you should look up which gear goes with you new 3.42 rear-end and source that out.

As for the install you're in luck.

All you have to do is jack the car up from the rear, CHOCK THE FRONT WHEELS

look on the tail shaft of the tranny

there will be the VSS (vehicle speed sensor) on the driver's side, it has a plug and two wires coming out of it.

Take what i believe is a 3/8" bolt out of the hold down and pop the vss out. WATCH OUT FOR LOADS OF TRANNY FLUID.

There will be a colored plastic gear on this vss, just remove the gear on there and replace with the correct gear.

 

Well, when I originally asked what speedo gears to get over a year ago, I was told I needed to get 2 gears. One was cone shaped, and the other was a ring shape, right. They said I need a yellow and a grey.

Are you saying that I only need one gear to correct the speedo?

 

Don't quote me but as far as I know, the only gear you need is the cone shaped one on the VSS.

 

I have no experience with auto trannies, but with a T5, both the drive and driven gears would have to be replaced if you went from 2.xx to 3.42's.

https://www.thirdgen.org/speedogear

JamesC

 

For an auto trans and 3.42's

15-tooth grey drive gear (#8642620)
41-tooth yellow driven gear (#25513048)

17-tooth red drive gear (#8640517)
45-tooth light blue driven gear (#25513052)

Check to see which drive gear you have in the tail shaft. Match it to one of the above. Good luck!

 

Here's a great writeup on it Click Here

And I did the same swap with the yellow and gray gears. Speedo is right on, I've paced brand new cars, all good

And with the 2.7 rear, both stock gears were red. So I suppose you could just change to a 45 light blue and keep the red gear on the tailshaft. But IIRC, 15 and the 41 is more accurate. And is is way easy to do.

 

okay well i wasn't sure if the one in the tailshaft was replaceable... or really existed lol good to know

 

How much more accurate do you think?

 

Well IIRC, the 15/41 combo just puts me a shy under indicated speed, whereas the 17/45 combo puts your actual speed just over indicated speed. I choose the 15/41 combo because when I drive and I see 65 MPH on the speedo, I know I'm safe. Didn't want to worry about going an indicated 65 and getting pulled over for speeding. (speed limit is 55 around here). I also have the occasional other driver when I've been drinking. So I felt it safer to go with the 15/41.

Also, for thoose you you with a manual tranny, here's a good tech article on the gear swaps, click here.

 

Okay check this out:

Tire Size Calculator - tire & wheel plus sizing

^^Hope that posts my search I did.....**edit didn't work**

Anyway, the car came with 215/6r16 wheels stock. With the 245's, the speedo would be less than 2% too fast. With 255 tires, the speedo would be less than .5% too fast.

Now since I have 245's already on the car, which the speedo would be 2% too fast, with the blue gear you said made the speedo read 2% slow. Now if I just put the blue gear in, it should match perfectly. Or am I wrong and extremely confused?