Quote:
Originally Posted by MAStuart
As far as highway RPM's . Is your Richmond gear trans a non overdrive 5 speed? I so you must be running low rear gears with shorter rear tires. That combo needs a high rpm motor to use first and second gear . Change the rear gear to a 3.25 with some taller rear tires and your highway rpm's will be lower. That combo will still take off like a car with 4.11 and a close ratio 4 speed.
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Yes, I believe Richmond Gear called the trans model "4 +1" and 5th gear is 1:1. In addition to the lack of overdrive, the transmission (with a Hurst Competition Plus shifter) has never shifted very well from 2nd to 3rd. I've spent many, many hours adjusting it and changed out the shift linkage bushings to the best steel ones available. For up shifts over 3,500 RPM, the shifter has a tendency to "stick" between gears. The higher the RPM the more likely the shifter to stick. The trans is still in 2nd gear but the shifter is essentially "locked up" and thus no gear can be selected while car is moving. To free up the shifter, the car must be brought to a full stop, shifted into reverse, and once reverse gear is engaged it sets all the other gears to neutral. Bringing the car to a full stop to unstick the shifter can be a real safety hazard especially on curved mountain roads.
The current rear end gears are 3.5 ratio and tires are 255/50ZR - 16. The Tremec RPM calculator says that a TKX with .72 OD would give 2,440 RPM at 75 mph. That sounds about right for a 5.0L motor. This trans has a 3.27 first gear so it should also be good for a quick launch.
So the net of all this, I'd much rather change out the transmission and leave the rear end gears alone. Even though this will cost more, my frustration level with the Richmond Gear trans is such that it's got to go.