Manually Downshifting an A4
Staging Lane
Joined: Jun 2004
Posts: 52
Likes: 1
Originally Posted by narc
First of all let me set you all straight. Downshifting from OD to 3rd is not good on your 60E. you can do it every now and then "I QUESS" but be warned. Downshifting from O/D to 3rd brings the over-run clutches on. Continually doing this will break the lugs off the over-run hub of the input sprag. "Do not" backshift the lever without giving it some throttle to match the rpm's.
So if you want to replace a new tranny go ahead and keep trying to downshift it.
So if you want to replace a new tranny go ahead and keep trying to downshift it.
To quote TeamTripp (who is a GM technician):
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If you have to downshift from 4th to 3rd under load, doing it manually is the best way. If you just punch it, the sprag has to go from and overrunning state to a locked state to transfer the torque and this "shock" can be damaging.
If you manually downshift, the overrun clutches apply at the same time the sprag has to lock, therefore reducing the torque input on the sprag elements as they begin to hold, decreasing the failure rate.
__________________
GM "World Class" Technician
Performance Transmission Builder
TeamTripp, LLC
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It boils down to this: Downshifting the trans and racing in general are going to shorten its life. If you're going to race the car either way.... there is very substantial evidence that says manually downshift the car at the lowest speed you can, *not* under load, as opposed to just flooring it and "letting the transmission do the work."
What's the reason for this? It has absolutely *nothing* to do with you "trying to shift better than the computer", or any such foolish concept. It is quite simply: Downshifting at WOT is MORE damaging than downshifting lazily with the engine not under load. You are not performing the same task "better" than the computer. You are performing 2 completely different tasks.
One of them is 4-3 shift under load
The other is 4-3 shift *not* under load.
The latter is less damaging.
