Overdrive ratios for Magnum XL

DBcooper

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I've been accumulating parts for months, and I'm finally about ready to swap a magnum XL into my 05 GT. I've already decided on the close ratio 2.66 1st gear model. I currently have 4.10 rear gears. I'm debating which overdrive gears to go with and looking for some second opinions.

Option A: 0.74 5th gear and 0.50 6th gear. 65 MPH would be around 1650 RPM in 6th gear.

Option B: 0.80 5th gear and 0.63 6th gear. 65 MPH would be around 2075 RPM in 6th gear.

Option A would be nice for highway cruising but probably a little sluggish. Option B would be a little more responsive but a little worse on gas mileage. Option B 6th gear is very close to my current tremec 3650 5th gear. I'm not concerned at all with top speed - both would be capable of well over 200 MPH which is way too fast for my blood. The car is primarily a street car that's only driven on the weekends. It makes an occasional trip to the drag strip. Just curious which option you would choose if you were in my shoes.
 

Dino Dino Bambino

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In my case neither.
I'd have preferred my TR3650 to have come with a 2.97:1 ratio 1st gear so that I land at peak TQ rpm (4400) in 2nd gear when I shift up at 6500rpm, plus an extra 0.82:1 ratio between the 1.00:1 4th gear and the 0.68:1 5th gear to bridge the yawning gap.
Thus the following ratios would be right on the money for me:
1st 2.95 2nd 2.00 3rd 1.32 4th 1.00 5th 0.82 6th 0.68
 
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DBcooper

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In my case neither.
I'd have preferred my TR3650 to have come with a 2.97:1 ratio 1st gear so that I land at peak TQ rpm (4400) in 2nd gear when I shift up at 6500rpm, plus an extra 0.82:1 ratio between the 1.00:1 4th gear and the 0.68:1 5th gear to bridge the yawning gap.
Thus the following ratios would be right on the money for me:
1st 2.97 2nd 2.02 3rd 1.32 4th 1.00 5th 0.82 6th 0.68

I figure the close ratio would be better than the wide ratio because I wouldn't lose as much RPM between shifts. This would allow me to stay up in the power band a little better. I wish the 2.66 was lower, but I could always swap my 4.10 out for a 4.56 rear gear if I felt it was necessary.
 

JC SSP

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Option B would mirror the T3650

I am curious, what are the 2, 3 and 4 gears of the magnum XL? I am assuming 4 is 1:1.
 

JC SSP

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Thx for the info.

Once you install… run through the gears to your highest rpm and shift, then see where you rpm goes after every gear change. (Shift point recovery) You want them right at the beginning of where your power band starts, but I think your good with 4:10.
 

Pentalab

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Why does the magnum XL come with 2 overdrive gears ? A .5 for 6th gear seems absurd, unless you have a 3.90 / 4.10 / 4.56 rear end gear.

What are the gear ratio's in the GT-500 cars ? I think the GT-500's came with only one OD gear, not two.
 

Midlife Crises

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I have a T56 Mag XL in my 2010 GT. The 2.66 first works great with 4.30 or 4.10 rear gears. First and second gear seem very close together. Third and forth are freight train gears. It has the 0.63 top gear and is comfortable above 65 mph. Feels sluggish below that speed. I would not chose the 0.50.
:driver:
 

DBcooper

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I have a T56 Mag XL in my 2010 GT. The 2.66 first works great with 4.30 or 4.10 rear gears. First and second gear seem very close together. Third and forth are freight train gears. It has the 0.63 top gear and is comfortable above 65 mph. Feels sluggish below that speed. I would not chose the 0.50.
:driver:
That’s the way I was leaning and exactly what I wanted to hear
 
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I have the 2.66 gear set with the .50 6th gear.

Initially I ran 4.10s in the rear. You could absolutely purr down the highway in 6th at 80 mph, but 55-65 mph I'd find myself downshifting to 5th for hills on the highway.

I've since changed to a 4.88 rear gear to help the starting line ratio at the strip. The .50 6th gear has been my saving grace here, I can still manage 65 mph in 6th around 2000 rpm.
 

Juice

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I have "option B" with 3.73s. I wish I went with the 2.66 first and .5 6th. Im in the 2000-2300 rpm range on the highway.

Agree w/two OD is pointless. But the MT82 was never an option for me due to it being so fragile.

You will need to update the tune with the new gear ratios, or cruise will only work in some gears.
 

DBcooper

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I’ve thought about going with the .5 6th and changing the rear gear if needed. It would be a lot easier to change the rear gears than the transmission overdrive gears
 

MrBhp

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I think the gear ratios on the XL are bizarre. First gear is way too tall. So I would need at least a 4:88 r&p. But then I lose too much in 6th. No good options for me. I'm thinking about trying a built 3650. My turbo setup is easy at launch. It might live. Third or fourth might be the weak link. Long pulls at high torque are awesome! Unless you're a transmission. And having one less shift means one less boost losing event. Just my irrelevant dos pesos.
 

Pentalab

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What ratio's are used in the 6 speed on the GT-500's ?? (TR-6060).
I thought it only had ONE OD gear....and the tranny was a T-56 magnum derivative.
 

Midlife Crises

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The 6060 has two (5th and 6th) overdrive gears. 4th is one to one. It looks to me like the GT 500 6060 had a 2.97 first and a 0.62 sixth from 07 to 09. 5th would be 0.80. In 2010 fifth and sixth was changed to 0.74 and 0.50.
 

Pentalab

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The 6060 has two (5th and 6th) overdrive gears. 4th is one to one. It looks to me like the GT 500 6060 had a 2.97 first and a 0.62 sixth from 07 to 09. 5th would be 0.80. In 2010 fifth and sixth was changed to 0.74 and 0.50.
Tnx. Somewhere along the line, the GT-500 rear end gear went from a 3.73 to a 3.31. I THINK that was in 2013. Local fellow had a 2013/2014. It would do an easy 60+ mph, in 1st gear.

I think the 2nd gear in my 2010 auto is 2.60 The 2010 auto came with a 3.31 rear gear. Essentially the GT-500 in 1st gear was the same as my 2010 in 2nd gear.

The story I got was the gear change in both the tranny and rear end gear on the later GT-500's was done to get around the..'gas guzzler tax'.
 

Dino Dino Bambino

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In my case neither.
I'd have preferred my TR3650 to have come with a 2.97:1 ratio 1st gear so that I land at peak TQ rpm (4400) in 2nd gear when I shift up at 6500rpm, plus an extra 0.82:1 ratio between the 1.00:1 4th gear and the 0.68:1 5th gear to bridge the yawning gap.
Thus the following ratios would be right on the money for me:
1st 2.95 2nd 2.00 3rd 1.32 4th 1.00 5th 0.82 6th 0.68

The gear ratios in the original TR-6060 are as follows:

2.98/1st
1.78/2nd
1.30/3rd
1.00/4th
.80/5th
.63/6th

Very close to what I'd like except for the excessively tall 2nd gear.
 

JC SSP

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I am only familiar with the BW T-5.

Stock 3.35 first gear was a waste even with 2:73 or optional 3:08 rear. I had 3:27 for a long time and those worked great with N2O but I like running on mostly motor.

As modifications advanced I went with 3:55 and then quickly went with 3:73.

I went through several T-5 (blown 3rd gear cluster) then I installed a world class T-5 2.95 first gear with liberty pro-shifter 3 and 4. Have never had a problem since.

The 2.95 first with 3:73 rear allowed me to get out of the hole and get the car rolling so I can stand on it.

My little Fox coupe is different to my 05’ GT but the concept of putting power to the ground and matching engine power band to shift recovery point is the same.

PS my combination is actually designed for 4:10 gears w/28” tire but it runs sooooo good with the 3:73 w/26” shorter drag radials that I don’t want to mess with it to gain a couple of tenths.
 

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