PUCampin wrote:
The other thing these 5, 6, 8, 9 etc speed transmissions do is eliminate the need to offer multiple axle ratios. Now the mfr can pick one axle ratio to offer that optimizes mpg when not towing, and the deep first and second gears handle the situation when towing. Example - Expedition with 3.31 axle and 6 speed with 4.17 1st = 13.8 crawl ratio. This is lower than the old 4 speed (2.84 1st) paired with even a 4.56 (12.95)!!! The 3.08, long considered horrible for towing, when paired with a 6 speed is STILL lower than the 4 speed with 4.10 (12.84 0 11.64).
Yet I still see some members on here that don't recognize this, and immediately jump on a poster who says "My new Expedition / Suburban has 3.31 or 3.08" OMG!! Those are NOT towing gears, you need at least 3.73 or 4.10!! Turn in yor towing card, your new SUV is going to fall on it's face!! Not so any more.
Absolutely right, and electronics allow the trans to be programmed for a 2nd gear start when tow/haul switch not engaged, and can lock out the tall OD gears when towing.
