Speedo recalibration gear chewed up.

[leakyfaucet]

Hi, I bought my car with a T5 (not sure which year) and 3.73 gears. The speedometer was off and I was told to correct it with a white 23 spline speedometer correction gear from steeda. It was perfectly accurate. But after about 5,000 miles I noticed my speedometer needle vibrating while maintaining a speed. I checked out the gear, and sure enough, it was chewed to pieces.

Is there another gear size I should try out or is this replacing the gear every 5,000 miles just something people deal with? I've heard for some T-5s you have to use a 21 spline speedometer gear. Anybody know which I need? I'm not sure the year of T-5 I have, and I'm pretty sure that's how you tell the difference. Any way to check?

Thanks a bunch!

 

[Maryland Stang]

The white 23 tooth is correct for your car if the speedometer was reading correct. The 21 tooth will make your speedometer read fast.

If you're speedometer says 55 you'll really only be doing 50.

You could switch the driven gear to a 7 tooth and the drive gear to a 20 tooth and it should fix the problem.

 

[trbkrb]

The problem is that the 23 tooth gear is not a "real" gear for our T5 trannys. It is a Jeep T5 gear. It does not mesh quite right with the drive gear on the output shaft, so it sometimes gets chewed up. One way to make it more accurate is like Maryland Stang mentioned to change the drive gear on the output shaft and then get the correct driven gear for the cable.

To Id your tranny, if it has the tag on it, here is a chart: http://ddperformance.com/Trans ID chart.htm

FWIW, I have a 7 tooth drive gear, and with the 21 tooth driven gear, my speedo still reads about 8% too fast. It reads 60 when I'm going about 56, per the radar speed signs and riding along our Yukon with an electronic speedo.

 

[squeeeg]

That happens with the white gear sometimes. You can either replace it or change the drive gear in the tranny. From what people say it isn't too difficult to change it. 8tooth gear(which you have) you need the 23 tooth gear and for the 7 tooth you need the 21 tooth gear.

trbkrb - it sounds like at some point in time you got an 8 tooth gear in your tranny. Have you ever put in a new transmission? Or is there a chance that you got the 3.55 thunderbird rear end? Just asking

 

[trbkrb]

My tranny was replaced in 91 with a FMS WC replacement, which should have the 7 tooth drive gear. It read perfectly fine for 11+ years with the stock speedo gear before I did the rear end swap. I pulled the rear end from an auto TC. I counted the revolutions, it was about 3-3/4 turns per wheel rotation.

Next time I pull the tranny, I might look into making it more accurate if the 6 tooth drive gear will help, or maybe just get a ratio adapter. It doesn't bother me too much, except for putting extra miles on the speedo.

Thanks for the ideas.

 

[jrichker]

Check to see if there is a speedometer shop in your area. If there is, ask about the Stewart-Warner speedometer gearbox. I believe it is either a 777 Series Drive Joint Kits and Parts or 666 Series Drive Joint Kits and Parts. It is a small gear box that fits between the speedo pickup gear on the transmission and the speedometer. It has quick change gears that allow you to choose almost any tire size and rear end gear ratio you want. This will allow you to get the accuracy with within 1%-3%. The drawback is that it isn't cheap.

See http://www.gaugeguys.com/ratioadapt.htm for more info.

 

[ss93cobra]

Order another Steeda gear. We're a distributor for them and they are aware of problems with them. They had 1 gear to work for an auto as well as a manual and they knew some of the gears would be an issue and were weak. I went through the same thing with mine a while back. Now they have 2 seperate gears for auto vs. manual and my new one has been just fine.