S10 T5 elect speedo

Thx Action, that was my next question. As expensive as that box is it seems wiser to just find the S10 tremec w mechanical & pay the extra.
Whats the last year the S10 used the mechanical speedo on the tremec 5 soeed?
 
V8COOPMAN said:
What are ya workin' on, Tony? You've got my "T5" curiosity cranked-up!

Coop


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Hi Coop, planning ahead! Had another back surgery but planning ahead. Not sure if I’ll do it or have it done ( depends on how much recovery allows) but regardless I noticed such a great diff for the positive w the hydraulic brakes I’m driving the ‘35 a lot more! As u’ve read in previous thread I gotta make it easier to steer & this is to make shifting more of a pleasure than work! I’ve found a guy thru an old acquaintance in N Phila. whose shop does all kinds of custom stuff in South Jersey https://www.hrgperformance.com/ think I’ll bite the bullet & let him do it all! I just want him to do what I want & gather parts to do!
Best
Tony
 
Just a case in point - if you convert your T-5 to mechanical speedo drive you will only get close to your actual speed reading in 4th, its 1:1 ratio. 5th gear will be off around 8% give or take with tire size, rear gear ratio, and your 5th gear final output. I have a 32 5-window with an 88-93 Cobra 5-speed, 5th gear being a .72. My tire size is 235/85-r16 (almost 32 inches tall), rear gear a 3:23 (9”). In 4th I reads almost perfectly correct according to my gps. 5th gear however is off. @65 on my speedo, my gps reads right around 60 - about 8% off. At least it’s in your favor, right?!?! The faster you go, the greater the difference. A small price to pay and no big deal. Your stock 40 Ford speedo cable will screw directly into the mechanical T-5 gear btw. In this same car I have 35 Buick gauges and it bolts directly into the T-5 as well ….

Good luck!
 
TomT/Williamsburg said:
Just a case in point - if you convert your T-5 to mechanical speedo drive you will only get close to your actual speed reading in 4th, its 1:1 ratio. 5th gear will be off around 8% give or take with tire size, rear gear ratio, and your 5th gear final output. I have a 32 5-window with an 88-93 Cobra 5-speed, 5th gear being a .72. My tire size is 235/85-r16 (almost 32 inches tall), rear gear a 3:23 (9”). In 4th I reads almost perfectly correct according to my gps. 5th gear however is off. @65 on my speedo, my gps reads right around 60 - about 8% off. At least it’s in your favor, right?!?! The faster you go, the greater the difference. A small price to pay and no big deal. Your stock 40 Ford speedo cable will screw directly into the mechanical T-5 gear btw. In this same car I have 35 Buick gauges and it bolts directly into the T-5 as well ….

Good luck!
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What?! How come the S-10 the transmission came out of didn’t have this problem? The speedo gear is at the output shaft, not before the overdrive gear. The speedo gear will give you the actual RPM of the driveshaft.
 
Hey - believe me or not, the numbers don’t lie. My avatar has a 5-speed in it of which the tire size, rear gear ratio, and the .86 5th gear output to be running 2500 rpm at 75 mph. U have designed it this way to run long distances at speed as this is where a flathead likes to be at speed imho. Google rpm calculators and play with the numbers. Sure my speedometer will read some kind of speed but not 75 like my gps is telling me. GM built their vehicle as a small pickup DD with all gm parts. I have a mix of parts from different eras, manufacturers, etc - all bets are off.
 
Your speedometer isn't correct for 1-4 but off for 5. That's simply not how the speedometer gearing works within the transmission, and it's irrelevant to whatever you have between the speedometer drive and the road, or between the drive and your dashboard. It's agnostic as to what mix of brand, year, or type of parts you have.

Your speedometer is off by the same X% from 0-∞ in all gears. Run up to 60 MPH as measured by your GPS. Note what your speedometer is indicating in 4th gear, then shift to 5th. It'll stay the same.

You need to do some calculations based on your tire diameter and differential ratio to determine which speedometer drive and driven gears are needed to minimize that error percentage.
 
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