Do I have stock gears??

[fish30250]

I recently purchased a 1996 Mustang Cobra.
The car is a 5 speed, and tach's at about 2100 at 60 mph in fifth gear. The car is supposed to have 323 gears, but this rev seems a little high. Is this normal for 323 gears at 60 mph?

Thanks guys,
Jason

[95GTS]

There are no such thing as 3.23s for an 8.8" rear end which your car has. It might have 3.27s. I don't know. 97snakedriver and some of the other cobra owners can help a little more on that. You can check for yourself, though. Crawl under the rear of the car and look at the metal tag on the differential (side facing the rear of the car). Look for (I can't remember if it's the top or bottom line) numbers such as 3L27. This means you have 3.27 gears and the L stands for the positrac. If it reads 3 27 then you have 3.27s w/out posi. It could also read 2L73, 2 73, 3L08, 3 08. Those are 2.73s or 3.08s. L meaning positrac. I've found this to be the easiest way cause you don't have to hunt down or buy a manual to read the VIN and you don't have to jack up the car and turn the wheels and drive shaft which are other ways of checking your gear ratio.

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FOR SALE: 1996 Mustang GTS: 5-speed, K&N, removed air silencer, 3.73s, 48,000 miles. $11,500

[T_Bone]

What are the rpm's at 70? I have 4.10's in my Cobra, at 70mph it reads 2600rpm. I think around 2400 at 60. Maybe they're 3.73's.

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T-Bones 1997 Cobra
Wht/blk, Pro 5.0, 4.10's, FRPP throttle body, C&L MAF, K&N, off-road H, Flowmasters, s/f connectors, FRPP pro springs, BBK caster/cambers.

[97snakedriver]

Hmmm. There is always some tach error, but it sounds like you have 3.73s. 3.27s were the only gears that came stock. With 3.27s you should be between 1800-1900 RPMs at 60 mph. If you are exactly at 2100 rpms @ 60 then you would have 3.70s (3.73 is the closest available ratio for the 8.8). If they were swaped by the previous owner then the tag will be inaccuriate. Maybe he meant 3.73 instead of 3.23?

The best way to tell is to jack up the rear two wheels up with the car in neutral. Put a chalk mark on the very bottem of the drive shaft and have a friend rotate the rear wheel exactly once, slowly. Count how many times the drive-shaft rotates for each rotation of the wheel. Conveniently if you have 3.27s the mark will end up on the driver's side. If you have 3.73s, it will end up on the passenger's side. If you have 3.55. it will end up pretty much right on top.

3.73s aren't bad for a Cobra. You shouldn't see any loss in milage, and your car should run a bit quicker. So unless you want to keep the car completely stock, or are looking to do some serious modifications, they will work just fine.

[95GTS]

I've got 3.73s in my stang and at 70 I'm at 2500 rpm and at 85-86 on the speedometer with a 21 tooth speedometer gear up from the stock 18 tooth. I think at 60 i'm a bit over 2000. (all in 5th of course) I'm not sure about the 60 cause I rarely run at that speed and don't pay much attention around there. The 23 tooth, which is recommended to correct the speedo, has too many teeth and doesn't mesh with the 8 tooth internal gear and gets chewed up in about a month. A 7 tooth internal is needed with the 21 tooth speedo to correct the 3.73s but unfortunately a 7 tooth internal is not made for the T45, only the T5 which will not work because of different splines on the gear.

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FOR SALE: 1996 Mustang GTS: 5-speed, K&N, removed air silencer, 3.73s, 48,000 miles. $11,500

[97snakedriver]

I've had my 23 tooth gear for about a year now. Works fine so far.

Thinking of speedo gears, that's another way you can tell. Its placed at the very back end of the tranny. Takes all of 5 minutes to pull out and replace. The stock peice is pink. With 3.73s it would be red.

Anyway, the stock drive gear in the 96-98 Cobra T45 is a 7 tooth gear(Yellow). The GTs have an 8 tooth gear(Green). With a 21 tooth driven gear(Red) and a 7 tooth drive gear, you should be right on with 3.73s.

I went with the 23 tooth gear, as a cheaper alternative to installing a 6 tooth drive gear (black) and 20 tooth driven gear (black) just because installing a drive gear was turning out to be more pain then it was worth.

Anyway, 96GTS the service part number for the T45 7 tooth drive gear is: E3ZZ-A. Costs like $15 bucks. They'll probably have to order it, but you can get it at any Ford dealership though the parts counter.

[95GTS]

97snakedriver: I have researched high and low and could not find a 7 tooth for the GT. For some reason they decided to make the 7tooth different for the cobra than for the GT. We ordered one for the cobra and the splines on the inside of the gear are different from the GT. All straight from Fordmotorsports. You Cobra guys got it good. Unless you know another type. Oh well, that was done when the trans was apart this summer and I'm not about to go thru that again. Thanks for the info. I should have clarified GT T-45 in the previous response. I had forgotten till you mentioned it that the Cobra and GT trans are a bit different.

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FOR SALE: 1996 Mustang GTS: 5-speed, K&N, removed air silencer, 3.73s, 48,000 miles. $11,500 http://www.mustangworks.com/cgi-bin/moi-display.cgi?388

[This message has been edited by 96GTS (edited 10-17-2000).]

[97snakedriver]

Originally posted by 96GTS:
I had forgotten till you mentioned it that the Cobra and GT trans are a bit different.

That's real obnoxious isn't it? I wonder why that is.

[95GTS]

No joke. I like Ford vehicles but, man, they have to make it so freakin' difficult.

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FOR SALE: 1996 Mustang GTS: 5-speed, K&N, removed air silencer, 3.73s, 48,000 miles. $11,500 http://www.mustangworks.com/cgi-bin/moi-display.cgi?388