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Gear ratios


AL

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Getrag HM-284 gear ratios:

 

1st 3.46

2nd 2.28

3rd 1.48

4th 1.09

5th 0.72

Axle 3.67

 

This means at the 7000rpm rev limiter with 245/50R16 tires (and the more common 225/60R16 tires are 3% taller) you will be at the following speeds (I've GPS'ed these):

 

1st 40mph

2nd 61mph

3rd 95mph

4th 130mph

5th a LOT (about 200mph if you had the power)

 

But most hit the top speed governor around about 124-127mph at 6600ish rpm in 4th (4300ish rpm in 5th).

 

 

 

 

 

In *MY* opinion, 2nd could be about 5% longer (the 2-3 shift is too wide) and 5th could be about 5% shorter (it's worthless except as a cruising gear), but 1st, 3rd and 4th are fine............

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Getrag HM-284 gear ratios:

 

1st 3.46

2nd 2.28

3rd 1.48

4th 1.09

5th 0.72

Axle 3.67

 

This means at the 7000rpm rev limiter with 245/50R16 tires (and the more common 225/60R16 tires are 3% taller) you will be at the following speeds (I've GPS'ed these):

 

1st 40mph

2nd 61mph

3rd 95mph

4th 130mph

5th a LOT (about 200mph if you had the power)

 

But most hit the top speed governor around about 124-127mph at 6600ish rpm in 4th (4300ish rpm in 5th).

 

 

 

 

 

In *MY* opinion, 2nd could be about 5% longer (the 2-3 shift is too wide) and 5th could be about 5% shorter (it's worthless except as a cruising gear), but 1st, 3rd and 4th are fine............

 

I know the ratios are different (also considering the 4T-60E has one less gear) at WOT, my car will shift at 6400 RPM at 45 MPH FWIW.

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If the gearing is anything like a 282, you will be well over 2k at 65 MPH.

 

My old 89 GP SE with the 282 5-speed did 2,000 RPM at 55 MPH and approximately 2,800 RPM at 70 MPH.

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My automatic is 2k at 60... Why wouldnt the five speed be lower?

 

Autos have overdrive. Some manuals do, but the 284 is just a 5-speed. 99% sure.

 

I didn't think our auto's had overdrive. I thought we had 4speeds and a tcc

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5-speeds still have overdrive. Any number lower than 1.000 is an overdrive gear.

 

My automatic is 2k at 60... Why wouldnt the five speed be lower?

Compare the gearing of your 4T60 versus the gearing of the 284. The autos are geared taller than the 282 or 284.

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So the 5th gear should be around the same ratio as overdrive right?

The number of gears in your transmission has nothing to do with how high it revs in top gear. It all has to do with gear ratios.

 

For example, the 4T60HD in my TGP has the following gear ratios:

 

1st 2.92

 

2nd 1.56

 

3rd 1.00

 

4th (OD) 0.70

 

Final Drive: 3.33:1

 

Now look at this. Any gear ratio that is higher than 1.000 is an UNDERDRIVE. Any ratio that is equal to 1.000 is a DIRECT DRIVE. Any ratio that is lower than 1.000 is an OVERDRIVE.

 

Now being that the 284 has a higher Final Drive and a higher top gear ratio, it is going to rev higher than a 4T60.

 

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if you go back to that link and click on (click hear for application details) next to 4t60-E it gives a list of cars it was in with ratios and it tells about the lq1

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if you go back to that link and click on (click hear for application details) next to 4t60-E it gives a list of cars it was in with ratios and it tells about the lq1

 

3.43 FDR with a 2060 stall. Thanks again.

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