Learned Something New Today...

ID89GT

10 Year Member
May 26, 2008
1,659
18
49
Spokane Valley, WA
That not all 4 eye gauge clusters are the same lol. I went to swap the cluster from my 85 to my 80 because I wanted the 140 speedo in the 85.. Well once I plugged it in, the brake light and the right turn signal bulb were on and the key wasn't even in. Then I started smelling a burning smell and sure enough the back of the gauge cluster is smoking -.- Well lesson learned not all 4 eye gauge clusters are interchangeable. So here comes to where I need help, what years ARE interchangeable since I need a new cluster for my 85 Mustang now lol. I also figured out all I had to do was pull the lense off and 2 bolts on the back and bam, speedo comes out..

I also have another question that kinda ties in with the first question.. Now that the 80 Mustang has an 85 speedo instead of the 140, what speedometer gear do I need to make the speedo read correctly again? It does have 373 gears, and is a t5 trans. Thanks :)
 
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What year T5 transmission and what tire size to you have?

See http://www.fordracingparts.com/download/charts/129.pdf for a chart by Ford Racing Performance Parts

Or see http://www.latemodelrestoration.com/page/Mustang-Speedometer-Gear-Application-Guide

Or see below...

frpp-speedo-gear-chart-gif.72422


Or see http://www.latemodelrestoration.com/page/Mustang-Speedometer-Gear-Application-Guide
 

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That not all 4 eye gauge clusters are the same lol. I went to swap the cluster from my 85 to my 80 because I wanted the 140 speedo in the 85.. Well once I plugged it in, the brake light and the right turn signal bulb were on and the key wasn't even in. Then I started smelling a burning smell and sure enough the back of the gauge cluster is smoking -.- Well lesson learned not all 4 eye gauge clusters are interchangeable. So here comes to where I need help, what years ARE interchangeable since I need a new cluster for my 85 Mustang now lol. I also figured out all I had to do was pull the lense off and 2 bolts on the back and bam, speedo comes out..

I also have another question that kinda ties in with the first question.. Now that the 80 Mustang has an 85 speedo instead of the 140, what speedometer gear do I need to make the speedo read correctly again? It does have 373 gears, and is a t5 trans. Thanks :)
Nothing, swapping the speedo will not be affected by what speedo gear you have, speedos are cal'd to display speed according to a std cable rpm that ford uses from year to year. I swapped a 140 into my 88 replacing the 85 mph gauge and it worked just as the 85 did. Going the other way will have similar results. So if your speedo was accurate with the 140, it will also be accurate with the 85.
 
Been there done that! Swapped the 80 cluster into the 82 and fried the ammeter wiring. So----figured the pinouts on both and compared. Very different.

Reinstalled the 82 cluster and all was well. The dash harness is set to match the cluster. Both the 82 and 80 under hood harness seem to work, iirc. I still have the 80 engine bay harness in the car. It appears the under hood stuff pins in the same way, and the dash harness does the translation.

I think the 79s are also different than any that came later.