Speedo Gear Question

dkins419

New Member
Nov 14, 2004
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Michigan
I have a 88 GT 5 spd and the trans took a fly. I put a t5 from a 90 GT and it seems that the speedo is off a little bit. Do I need to change to a different speedo gear? I used the speedo gear that was in the 88 t-5. Now i know that the t-5's were upgraded from 265 to 300 lbs of torque rating, but did they change anything else?
 
dkins419 said:
I have a 88 GT 5 spd and the trans took a fly. I put a t5 from a 90 GT and it seems that the speedo is off a little bit. Do I need to change to a different speedo gear? I used the speedo gear that was in the 88 t-5. Now i know that the t-5's were upgraded from 265 to 300 lbs of torque rating, but did they change anything else?

Purely speculation here, and I really can't remember the specifics from one model year to the next but the 88's had an 85mph speedo right? The 90 I believe had a 140mph speedo, I think....
I don't know if the tailhousing gear in the transmission might be causing an issue. I assume you have the proper speedo gear for your rearend gear set.

Is the speedo needle moving fluidly? or is it bouncing? or is it just off a little?
 
It seems like its about maybe 10mph off when im on the freeway and about 5 mph in the city. Yes it is a 85mph speedo. Everything was fine before until i switched the trans and now i think i need a different speedo gear. Does anyone know for sure or is there a chart that i can look at?
 
the rear gears are 2.73s. The only thing changed was the t-5 transmission from a 90 GT. I used the speedo gear from my 88 t-5. I do have a 85 speedo and the 90's have the 140. I dunno what i have to do?
 
Ok, here is the deal. You need a yellow 18 tooth speedo cable gear (Ford p/n CODD-B or go to 50resto #LRS -17271H) for 2.73 gears and a '90 T5. You will be dead on with the 140mph speedo, I don't know if the 85 mph speedo makes any difference since I used to pin my gone but not forgotten '89's speedo needle on the BACK side of the pin so I don't think it makes a rip, but I am not sure of my facts re this part of your question. I do know that they changed the gear in the tranny tailshaft for 90 through 95 from a 7 tooth (what you had) to an 8 (what the 90-95's have) which is why you are off with your pre 90 speedo cable gear. Hope this helps you out.