do they make a speedo gear for 3.55 rear gears????

Nico93Cobra · 03-09-2003

hey im installing 3.55 rear gears and i was wondering where i can get a speedo gear for my 5-speed t-5 tranny. some one was telling me i have to replace the internal speedometer gearbut i was hping i could just change the external one.

KwikNotch · 03-09-2003

I assume you are doing the gear swap on the 93. The recommended gear is a 23 tooth outer speedo gear for 3.55s, but also for 3.73s. The speedo will not be completely accurate though, but it will be close enough to get you by without any problems. If you want it to be accurate, you must change the internal speedo gear to one from an 89 or older t-5.

EX20 · 03-10-2003

That sounds right. If you have a Ford Motorsport catalog, it has a table in it that shows which combination of tranny speedo gears are required for the different rearend ratios.

Nico93Cobra · 03-10-2003

thanks a lot, can i use the 23 tooth with the 89 t-5, would that be acurate?

KwikNotch · 03-10-2003

No, the 89 t-5 should use a 20 tooth. Here...

The production T5 transmissions for 1990-95 5.0L models use an 8 tooth drive gear as did the T-45 transmissions used in the 1996-98 Mustang GT. Most 1983-89 T5 transmissions used a 7 tooth drive gear as did the T-45 transmission used in the 1996-98 Mustang Cobras. Most AOD transmissions used either the 7 or 8 tooth drive gear.
Gear ratio / Speedo drive
********************* 6 tooth drive 7 tooth drive 8 tooth drive

3.27 ********************16*********19********** 21
3.55 ********************17********* 20**********23
3.73 ********************18********* 21**********n/a
4.10 ********************20********* 23**********n/a
4.30 ********************21*********n/a**********n/a

EX20 · 03-10-2003

That's the table

FoxChassis · 04-06-2008

'89 5.0L T-5s could have either a 7T or an 8T speedometer drive gear. It was a mid year change. Have to know which one you're talking about before you can get the correct speedometer driven gear. The engineering number stamped to the transmission ID tag will tell you. It'll either be E6ZR-7003-FB (7T) or E9ZR-7003-A (8T).

If you plan on using a 23T driven gear be aware that it is NOT a Ford gear and it DOES NOT mesh correctly with Ford drive gear. (The pitch and depth of the teeth are wrong.) A common result of that mismatch is sheared teeth (and plastic bits floating around inside your transmission fluid) and a then bouncing or inoperative speedometer. It is best that you change to a 7T or 6T drive gear and then get the approriate Ford driven gear.