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+--- Thread: 722.6 "overdrive" (/showthread.php?tid=7257)
722.6 "overdrive" - matfield - 06-15-2016
Hi Lads,
I'm in the process of working out final drive ratios for my project. One question I haven't been able to find an answer for is the final ratio on the 722.6 auto.
I have seen the ratio on wiki and Ole's site, but from my previous experience with auto boxes there is a drop in revs, after the final gear has been reached, and when the "overdrive" kicks in.
On the 722.6, when cruising in 5th gear, is there another drop in revs when the over drive kicks in, or is 5th gear the overdrive?
If there is drop in revs; at what road speed, and by how much does it drop, and what diff ratio are you running?
Thanks in advance
Mat
RE: 722.6 "overdrive" - erx - 06-15-2016
Hi, 5th gear ratio is 0.83 so propshaft is turning faster than engine. There is another drop in revs when torque converter clutch locks and then it's solid 0.83, before locking it is always slipping a little. If you use Ole's tcu then you can change on menu where ever you want it to lock, usually little under 90kmh. I use 2.65 at the moment, 3.27 was too slow on highway.
RE: 722.6 "overdrive" - Petar - 06-15-2016
All 722.6 transmissions have an 0.83 fifth gear.
http://www.cargister.com/calculator-gear-ratio
Here's a gearing calculator, just enter your final drive and tire size and it'll calculate engine rpm at different speeds
Edit:
erx is correct, there is also a slight drop in speed once the tc lockup clutch kicks in.
RE: 722.6 "overdrive" - matfield - 06-17-2016
Thanks lads,
so the final drive with torque converter locked is a true 0.83 ratio.
Mat