MustangWorks.com : Ford Forums - View Single Post - Tremec TKO II w/ 0.82 OD and 3.73 rear end... Mistake?

Treachery · 11-13-2004, 04:23 PM

Hi all.

I just had a Tremec 3550 TKO II (0.82 overdrive) installed in my '93 GT with a Vortech SQ-Trim blower and a 3.73 rear end.

The Tremec is great and i love it BUT my Mustang rev's higher on 5th gear than i would like it to. I knew that a 0.82 overdrive would push up the RPM's on 5th gear but didn't realize it would push it up as much as it does!

My observation:

Pros: less shifting from 5th to 4th; power is really "on demand" when on 5th especially with the Vortech- more RPM's.. more boost.. etc.

Cons: GAS! My gas guzzler guzzles more gas! 80 miles=1/2 tank gone (not my main concern however); RPM's too high- very difficult to cruise. LOSS OF HIGH END! My RPM guage matches my speedometer! @ 120mph the car is almost at the red and is working very hard.

Solution? - Drop the rear end from 3.73 to 3.55 ? Would acceleration be hurt thus my 1/4 mile time suffers?

For those who have a TKO-II with 3.73's.. Should i stay with 3.73's or go 3.55? I personally want to stay with 3.73 but the Cons out weighs the Pros.

11-13-2004, 04:23 PM	#1
Treachery Registered Member Join Date: Jul 2002 Posts: 38	Tremec TKO II w/ 0.82 OD and 3.73 rear end... Mistake? Hi all. I just had a Tremec 3550 TKO II (0.82 overdrive) installed in my '93 GT with a Vortech SQ-Trim blower and a 3.73 rear end. The Tremec is great and i love it BUT my Mustang rev's higher on 5th gear than i would like it to. I knew that a 0.82 overdrive would push up the RPM's on 5th gear but didn't realize it would push it up as much as it does! My observation: Pros: less shifting from 5th to 4th; power is really "on demand" when on 5th especially with the Vortech- more RPM's.. more boost.. etc. Cons: GAS! My gas guzzler guzzles more gas! 80 miles=1/2 tank gone (not my main concern however); RPM's too high- very difficult to cruise. LOSS OF HIGH END! My RPM guage matches my speedometer! @ 120mph the car is almost at the red and is working very hard. Solution? - Drop the rear end from 3.73 to 3.55 ? Would acceleration be hurt thus my 1/4 mile time suffers? For those who have a TKO-II with 3.73's.. Should i stay with 3.73's or go 3.55? I personally want to stay with 3.73 but the Cons out weighs the Pros.