very random but good trick
09-22-2007, 08:40 AM
#33
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Join Date: May 2007
Location: NW Arkansas
Posts: 13,322
RE: very random but good trick
ORIGINAL: lldsandsll
i'm not disagreeing, but i'd like to see the article that explains why downshifting is detrimentle
i'm not disagreeing, but i'd like to see the article that explains why downshifting is detrimentle
Are the gears in a manual tranny always cut straight
or are they helical cut? In a rear end the thrust is outward
towards the cover hence the need for a girdle cover. The
gears are being forced apart under acceleration. There are
good thrust washers/bearings for this load. Is there the
same type of thrust washer/bearing for when you downshift
and the gears are now being pulled together by the helical cut
of the gears? Now back to the tranny. Same gears, same loading
when downshifting, but a lot more of them? Putting sideways
thrust in the direction it was not designed for? I dont know.
Could someone extrapolate on my theory?
09-22-2007, 09:44 AM
#34
4th Gear Member
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Join Date: Feb 2007
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Posts: 1,885
RE: very random but good trick
In modern transmissions all the gears are constantly meshed, and never separate. All that moves is a collar that transferrs power to whatever gear you choose.
Hold on, let me find an article.
.
..
.
.
http://auto.howstuffworks.com/transmission.htm
Hold on, let me find an article.
.
..
.
.
http://auto.howstuffworks.com/transmission.htm
09-22-2007, 10:52 AM
#35
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Location: NW Arkansas
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RE: very random but good trick
ORIGINAL: 22kart22
In modern transmissions all the gears are constantly meshed, and never separate. All that moves is a collar that transferrs power to whatever gear you choose.
Hold on, let me find an article.
.
..
.
.
http://auto.howstuffworks.com/transmission.htm
In modern transmissions all the gears are constantly meshed, and never separate. All that moves is a collar that transferrs power to whatever gear you choose.
Hold on, let me find an article.
.
..
.
.
http://auto.howstuffworks.com/transmission.htm
But that does not explain thrust directions and gear cuts.
I see helical cuts all over the tranny in the pic.
[IMG]local://upfiles/69445/94B8D097D8C149D1831D70E9CE01AB71.jpg[/IMG]
09-22-2007, 11:35 AM
#36
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Join Date: Feb 2007
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Posts: 1,885
RE: very random but good trick
Oh, yes, you are correct. Sorry, I didn't notice your question.
Basicly, all you are wearing when downshifting are syncros (is that how you spell it) and collars, not to mention throw-out bearings.
As long as you match revvs you will be fine.
Basicly, all you are wearing when downshifting are syncros (is that how you spell it) and collars, not to mention throw-out bearings.
As long as you match revvs you will be fine.
09-22-2007, 04:22 PM
#37
2nd Gear Member
Join Date: Nov 2006
Location: Manchester, UK
Posts: 346
RE: very random but good trick
Gears are typically helical cut on the forward gears on a road car. Reverse is usually straight cut hence why you get the whine in reverse in most cars. There are a couple of road cars I can think of with straight cut boxes but I dont think there sold over there in the US generally track inspired kit cars.
09-22-2007, 05:04 PM
#38
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RE: very random but good trick
ORIGINAL: wozz
Gears are typically helical cut on the forward gears on a road car. Reverse is usually straight cut hence why you get the whine in reverse in most cars. There are a couple of road cars I can think of with straight cut boxes but I dont think there sold over there in the US generally track inspired kit cars.
Gears are typically helical cut on the forward gears on a road car. Reverse is usually straight cut hence why you get the whine in reverse in most cars. There are a couple of road cars I can think of with straight cut boxes but I dont think there sold over there in the US generally track inspired kit cars.
cut gears and under acceleration they apply thrust in one direction
against the thrust bearings and the case. Now during deacceleration
by downshifting and letting the clutch out, the gears are being forced
the other way. The question is, are the thrust bearings the same on
both sides of the gears? Maybe a look into the Ford Workshop Manual
will answer the question.
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