Deep mud and water for manual tranny
02-12-2008, 02:20 PM
#11
JK Super Freak
Its called double clutching (ironically)...in the days before synchromesh gears...that was the ONLY way to shift. 
In racing, we sometimes called it a power shift, etc.
Essentially, what you're doing is matching the rpm in the gear you're in, to what the new rpm will be in the new gear...so that the teeth are all turning in unison, and mesh w/o having to separate them with the clutch.
Newer (like the past sevral decades...) trannies have syncho's that spin the gears up as the teeth approach each other, to synchronize them for you/smooth the shifting.
One some large trucks, and on some OLD iron....you STILL have to double clutch, as there's no synchros, etc.
For a power shift, which is closer to what you do under water....you do the same thing, w/o the clutch...just blip the throttle as needed to get the gears in synch as you slap it into the next gear (Not a tentative move....either they mesh, or it makes a nasty grinding gnashing of teeth noise....you HAVE to commit to do it), you want the teeth engaged ASAP, no gently gliding them in...more like rrrrrrRRRRRRRR BANG! RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR!.
At least when racing.
In racing, we sometimes called it a power shift, etc.
Essentially, what you're doing is matching the rpm in the gear you're in, to what the new rpm will be in the new gear...so that the teeth are all turning in unison, and mesh w/o having to separate them with the clutch.
Newer (like the past sevral decades...) trannies have syncho's that spin the gears up as the teeth approach each other, to synchronize them for you/smooth the shifting.
One some large trucks, and on some OLD iron....you STILL have to double clutch, as there's no synchros, etc.
For a power shift, which is closer to what you do under water....you do the same thing, w/o the clutch...just blip the throttle as needed to get the gears in synch as you slap it into the next gear (Not a tentative move....either they mesh, or it makes a nasty grinding gnashing of teeth noise....you HAVE to commit to do it), you want the teeth engaged ASAP, no gently gliding them in...more like rrrrrrRRRRRRRR BANG! RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR!.
At least when racing.
02-12-2008, 07:53 PM
#14
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Its called double clutching (ironically)...in the days before synchromesh gears...that was the ONLY way to shift.
In racing, we sometimes called it a power shift, etc.
Essentially, what you're doing is matching the rpm in the gear you're in, to what the new rpm will be in the new gear...so that the teeth are all turning in unison, and mesh w/o having to separate them with the clutch.
Newer (like the past sevral decades...) trannies have syncho's that spin the gears up as the teeth approach each other, to synchronize them for you/smooth the shifting.
One some large trucks, and on some OLD iron....you STILL have to double clutch, as there's no synchros, etc.
For a power shift, which is closer to what you do under water....you do the same thing, w/o the clutch...just blip the throttle as needed to get the gears in synch as you slap it into the next gear (Not a tentative move....either they mesh, or it makes a nasty grinding gnashing of teeth noise....you HAVE to commit to do it), you want the teeth engaged ASAP, no gently gliding them in...more like rrrrrrRRRRRRRR BANG! RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR!.
At least when racing.
In racing, we sometimes called it a power shift, etc.
Essentially, what you're doing is matching the rpm in the gear you're in, to what the new rpm will be in the new gear...so that the teeth are all turning in unison, and mesh w/o having to separate them with the clutch.
Newer (like the past sevral decades...) trannies have syncho's that spin the gears up as the teeth approach each other, to synchronize them for you/smooth the shifting.
One some large trucks, and on some OLD iron....you STILL have to double clutch, as there's no synchros, etc.
For a power shift, which is closer to what you do under water....you do the same thing, w/o the clutch...just blip the throttle as needed to get the gears in synch as you slap it into the next gear (Not a tentative move....either they mesh, or it makes a nasty grinding gnashing of teeth noise....you HAVE to commit to do it), you want the teeth engaged ASAP, no gently gliding them in...more like rrrrrrRRRRRRRR BANG! RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR!.
At least when racing.
my DD is a large truck.
I rarely use the cluch while up and down shifting(double clutch from low to high range[18spd], and to get into 1st from a stop)Sometimes I wish my Jeep shifted like my Peterbilt. Syncromesh tranys are harder to "throttle" shift than the big trucks. I like the stick but have gott'n lazy about using a clutch while "throttle" shifting in a big truck for the last 15 yrs.
from Byron,GA today
02-12-2008, 08:03 PM
#17
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Sounds like I have something to practice! Wish I had a p.o.s. to grind gears in... hearin' the new JK grind isn't pleasant
Then again, I didn't buy it to treat it with kid gloves....
Then again, I didn't buy it to treat it with kid gloves....
02-12-2008, 08:14 PM
#19
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It's a clutch thing and it affects all clutch 4 wheelers. For my gearing and transfer case 2nd or 3rd (in low) is good for me. You don't want to haul through deep water/muddy water. While the actual transmission is a concern the issue is getting water between your clutch plates. Pushing your clutch in and out just adds more suction and there ya go. If you have to shift to keep moving then you gotta do it. It's worse to just sit dead in deep water. When your all done and safe at home make sure you check your diffs, engine oil, and transmission for water contamination. Keep in mind a hot differential hitting cold water makes it suck in, and that's the case for most of the drive train and engine.
02-13-2008, 03:16 AM
#20
JK Jedi Master
I'm confused, Teej. Double-clutching in my old Volkswagen Karmann Ghia without syhnchro's in first meant pressing and releasing the clutch twice--once in neutral to get the gears spinning at the same speed. Are you saying that shifting without using the clutch (to avoid getting water in the tranny) is also termed double-clutching?