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-   -   Non synchro reverse gears in various cars (https://www.team-bhp.com/forum/technical-stuff/30508-non-synchro-reverse-gears-various-cars.html)

Venkatesh.C 25th October 2007 22:31

Non synchro reverse gears in various cars
 
It has been often stated that Sx4/Swift have no synchro reverse gears and thats why the reverse is a bit notchy and does not engage properly in the said cars.
In another discussion a fellow bhpian sanchit highlighted a point that altos/800s or other cars like NHC which also apparently have non synchro reverses do not face this problem..

Why is this??? Some fundamental design goof up in Suzuki's side?

Calling upon the enlightened ones to shed some light.

Mods i tried searching for answers and could not find. If there is , pls do delete this thread.

dkamath 25th October 2007 22:50

Quote:

Originally Posted by Venkatesh.C (Post 606950)
a point that altos/800s or other cars like NHC which also apparently have non synchro reverses do not face this problem..

AFAIK, most of the cars would show up this problem once in a while.
to make you feel better, my maruti 800 has a problem with the 1st gear :),
and its miserable at times, especially when the signal goes green, and i'm still red :Frustrati, trying to lodge it into 1st gear

Venkatesh.C 26th October 2007 10:01

Now that you mention it I recollect that my alto and santro very rarely refuses to 'Completely' slot in. However the SX4 just refuses to enter the reverse gate and this occurs more frequently relatively speaking.
I have had over 6 Maruti 800s at various points in time and all of them have lovely gearboxes and never have had a problem with 1st gear. Is this something unique to your car? maybe a problem to be sorted out?

DieselFan 26th October 2007 11:03

Best way to overcome the reverse gear problem (Which one faces too frequently in Swift/SX4) is to slot the gear into 1st and then into the reverse without releasing the clutch. This has worked for me every time I have faced the problem.

srishiva 26th October 2007 11:12

Aren't synchros in place to help when the vehicle is moving ? Could be more of a gear problem than synchro.

You can try to slot into some other gear and then slot to reverse as suggested here.

flipsyde 26th October 2007 11:23

wat does synchro have to do with lodging gears when the car is stationary????

isnt it something to do with synchronizing the output shaft to the input shaft to avoid excessive wear and to ease the effort of changing gears when the car is in motion?

does ANY car have synchro on reverse????

im_srini 26th October 2007 12:21

Hi, reverse can be troublesome in my Alto too. I'm no mechanical engineer, but it seems to me that Venkatesh has a point...

As far as I know, gears continue to spin on their shafts due to inertia a few seconds or more after the clutch removes drive from the transmission. So, if you try to shift into reverse as soon as you come to a stop, wouldn't the collars rotating in one direction be forced to engage with the reverse gear which is rotating in the opposite direction ?

Of course, I'm assuming here that the reverse gear is constantly meshed like the forward gears (with the exception of the idler gear in between). Here, wouldn't some kind of a synchro help by slowing down the reverse collar ?

And if I'm not wrong, some cars do have a mechanism to minimize rotation of the gears when you shift to reverse. If however, reverse is achieved by actually slotting the idler between the input & output gears, then the gears have to aligned so that the idler fits in. In this case, trying a forward gear usually helps.

planet_rocker 26th October 2007 12:37

aah! i have faced this a lot of times in my padmini - the best solution is to put in 1st and roll the car an inch and then slotting it into reverse - works like a charm.

as for the m800 - i havent faced this issue at all - its better to stop the car properly and then engaging the reverse gear.

Venkatesh.C 26th October 2007 14:08

The reverse gear slotting problem occurs even when the car is absolutely stationary. THe problem of slotting reverse immediately after stopping from a forward motion is also there. But the case in context is more about slotting it when stationary and the solution is always slotting the gear in one of the forward gears and trying again without letting go of the clutch.
The question however is WHY????? :)

androdev 26th October 2007 14:40

Quote:

Originally Posted by flipsyde (Post 607374)
does ANY car have synchro on reverse????

I doubt it.. as u know, synchro allows you to shift from one gear to any gear irrespective of the RPM match.. while in motion.. this would mean you will actually be able to shift from top-forward gear to reverse gear and go really fast in reverse :-) but as u are not expected to shift into reverse on the fly (while in motion).. the need for reverse synchro is negligible and a good place to cut costs.

reverse not slotting:
the reverse is a straight-cut gear (spline). meshing spline gears requires 'exact' alignment that's why sometimes reverse doesn't slot in unless u somehow change the gear alignments (inch forward in a forward gear, or coast)

grinding noise when reverse:
this means the lay shaft is still rotating due to inertia.. and u are trying to slot in the reverse idle gear into a rotating gear.. thats why the grind.. if u wait for few seconds, there wont be any grinding.

sbasak 26th October 2007 15:02

I have a Suzuki Ignis and I sometimes too face reverse gear engagement problem. Sometimes it goes without a problem and sometimes refuses to go into slot. Then I usually go to 1st-2nd and then it goes. I've checked this with other Ignis owners and they said the same thing! :mad:

AFAIK none of the Suzuki cars has synchormesh on reverse. I don't know if other cars have it. But I do think I didn't face this problem in other cars. Some cars have (all GMs) reverse gear on left (with a ring to lift and then move gear shift to left) - there usually this problem doesn't exist.

A different grade of gearbox oil might help sometimes (not tested this myself).

In UK, WangonR sells with GM engine and gearbox, so - this problem doesn't exist!

nitrous 26th October 2007 17:36

Quote:

Originally Posted by dieselfan
Best way to overcome the reverse gear problem (Which one faces too frequently in Swift/SX4) is to slot the gear into 1st and then into the reverse without releasing the clutch.

the BEST reply here.

If it still refuses to budge, shift to 2nd and try again.
I learnt this trick from the off-roaders with mahindras who usually have problem slotting in gears when they shift to 4H or 4L.

theexister 26th October 2007 19:03

The same problem I face on my 1.4 Fiesta.
At times it slots into reverse like a charm but the rest of the time it just wont slot.
And yes getting into 1st gear & rolling an inch does work most of the time.

In the Fiesta manual its written to depress clutch for 3 seconds & then engage reverse and also ensure that the gear compresses a spring by pulling it to the right most extreme before slotting it downwards.

sidd_city 26th October 2007 23:28

Somehow I feel double clutching should solve the problem. cause i had the same problem in my Indica lsi v2. All I did was release the clutch and angage it again and the problem would be solved. Though have never faced this problem in my NHC the gears are like butter smooth.:Cheering:

rocksterraghu 27th October 2007 03:54

I second the solution given by dieselfan. That is the way I solve the problem in my Baleno.


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