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1984 CJ7 5-speed Speedometer question

1K views 13 replies 6 participants last post by  keith460 
#1 ·
I have an 1984 CJ7 5-speed with a dana 300.

I have 32" wheels/tires with 2.73 gears.

After looking around I think I need a 24 tooth speedometer worm gear, does anyone know where to get one. I can only find them to 26.

Josh
 
#2 ·
You won't ever find them, they're rarer then hen's teeth. I had one, along with the smaller size housing, but traded it when I made plans to swap gears. The gear swap has stalled, so I am just sticking with my 33-tooth gear :) I might consider getting a 26-tooth for it to be reasonably accurate, but at present I rarely go over 55 and I have a pretty good feeling for how fast I'm going based on prevailing traffic.

One thing I will say - with that T5, you might just consider swapping gears sooner rather than later. It just might save you having to replace your transmission in a few months. I went through two T5s in a couple of years, and I don't drive like a yahoo - same gearing, smaller tires (31s). That was why I originally planned to swap gears, until my T5 went out again and I just waited on a T176 that I rebuilt. A gear swap is hard for the 2.73s since you'll need a new carrier for the rear, or just swap axles entirely to save time and money.
 
#3 ·
There are ratio corrector's that you can purchase which attach at the transfer case and then the speedo cable attaches to them. The gears are easier to source. Here's a pic of one attached to my Dana 20:



I ended up not using it and going with a custom dash with an electronic speedometer that is calibrated off the VSS:

 
#6 ·
I was using it 99.99% on pavement. Hills, yes, but nothing like stops and starts on a hill or excessive climbing. The second T5 I don't think had more than 20K miles on it. It was the high strain put on it by starting off that finally snapped the shaft. With higher axle gears, that strain is less.

It's a big decision - to swap gears or change axles. It can be a major headache a lot of time and money spent. I can do transmission rebuilds and installs so that was easier for me. An axle swap I could probably do if I found the right axles, but a gear swap is out of my league.

My plan was to jump up to 3.73 with my 31" tires - which would require a change in both front and rear carriers. A 3.54 would only require a rear carrier swap, with new rack and pinion for both obviously. Either 3.73 or 3.54, new axles would be the easiest upgrade. With a T5 either is better than the 2.73s and that would allow you to use 5th gear with more frequency. With a 4spd something more along the lines of 3.31 would be better.

Again, you didn't come here asking for it but that's been my experience with that transmission. Based on others experiences and recommendations, my plan was to gear up.

The alternative is to try to upgrade to a T177 - they have better 1st spd. gearing and are generally better built for handling that sort of axle gearing. You're still stuck trying to find the right speedometer gear :)
 
#12 ·
Good God how the prices of speedo gears have jumped up in price. I bought several from the Jeep dealer when they were still around at a cost of $5.00 ea and I thought that was a lot. It's no wonder I hold on to them like gold, I don't know why, but I do.

For good mileage around town and decent highway acceleration, I would not go below 3.73 gears for the T5 and 32" or 33" tires. I have 4.10 gears with 32" tires and the T5 and love it. It's a great combo driving around my area with many hills and winding roads.

And yes, as others have said, a T5 trans with large diameter tires and 2.73 gears will destroy the trans in no time. Too much stress trying to turn the added weight and diameter of large tires without the proper gears. It's the reason the T4 and T5 get such a bad wrap as being a crappy transmission.
 
#13 ·
Some Dodge Vehicles (and yes... some newer Jeeps) used the same gears as our Dana 300s. Although they may use the short shaft version, you can easily pop the plastic gear off a short shaft and press it on the longer Dana 300 shaft. The plastic part of the long or short shaft version are the same. Tooth count, diameter, even gear color are the same.
 
#14 ·
That makes total sense to me and I can believe it. No manufacture will start from scratch just to make a new gear when millions out there already exist. Just changing shafts to accommodate the plastic gears is a common move of auto parts manufactures.

I remember giving my friend a Jeep gear for his Dodge Ram Charger in the 90's and it fit without issues. He needed it to correct his speedo when he installed larger diameter tires.
 
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