Gmt 900 6.0

[SWDoodle]

Anyone have a GMT 900 with the 6.0 and 4.10's? I was just curious to know what rpm is running 65 mph and if there would be much difference in mileage between the two gearings. From what I've researched it sounds like 4.10's are fairly rare to find in the new 6.0L's. I have always preferred the 4.10's, but maybe with the new 6-speeds it isn't as big of deal?

[96chevy7.4L]

4.10's with a 4 speed are good. But with the six speed 3.73 is as low as you can get. I have 4.10's with the 4L80 which is a 4 speed and I run around 2000-2200 RPM.

[yukon25008.1]

same here i have a 4speed with 4:10, and if i were to have two extras gears i would never want to be lower than 4:10,s if anyhting they should offer 4:56,s with a 6 speed for towing or pulling a load

[SWDoodle]

4.10's with a 4 speed are good. But with the six speed 3.73 is as low as you can get. I have 4.10's with the 4L80 which is a 4 speed and I run around 2000-2200 RPM.

 

 

According to GMC's site you can build one with the optional 4.10 gears for $100. I've just never seen one I guess.

[96chevy7.4L]

Well the 6 speed is geared very very low in the transmission. The ratios are close together from what I gather so it is keeping the engine in the power band a greater part of the time. The only issue forum members report is the 6 speed spends time searching for gears. The remedy is a blackbear tune. The handheld's don't have TCM support so a custom tune is the only way to correct it.

[RJG183SA]

Well the 6 speed is geared very very low in the transmission. The ratios are close together from what I gather so it is keeping the engine in the power band a greater part of the time. The only issue forum members report is the 6 speed spends time searching for gears. The remedy is a blackbear tune. The handheld's don't have TCM support so a custom tune is the only way to correct it.

Yes, you can get the optional 4.10. What type of use will your truck see? Unless you are hauling / towing heavy loads on hilly terrain, I'd opt for the 3.73. As for the reports of trans. gear hunting, I have not experienced this. Maybe this was a problem on earlier models and was fixed with software upgrades?

 

These are the ratios, the final drives in parenthesis. You can see how first gear offers over a 30% increase over the 4 spd. / 4.10 combo.

 

6L90E (3.73) 4L80E (4.10)

 

1st. - 4.03 (15.03) 2.48 (10.16)

2nd - 2.36 (8.80) 1.48 (6.06)

3rd - 1.53 (5.70) 1.00 (4.10)

4th - 1.15 (4.28) 0.75 (3.00)

5th - 0.85 (3.17)

6th - 0.67 (2.50)

[alaska511]

4.10's with a 4 speed are good. But with the six speed 3.73 is as low as you can get. I have 4.10's with the 4L80 which is a 4 speed and I run around 2000-2200 RPM.

 

 

 

Wrong.

 

I have 4.10s, it is an option

[96chevy7.4L]

OK I stand corrected. Last time it was mentioned 4.10's weren't available with the 6 speed. Perhaps that has changed.