NSH cruising at 130km/hr

[Chucky2007]

5w20 also can drive on NS way.. i drove to malacca and kuantan on 5w20, just maintain RPM. but my 5w20 is redline. i would't try with other brand on NS way

[Robo]

Sorry to side track abit, Wat about engine oil? 5W30 can hit NS highway?

 

i travel at 170km/h all the way on RL's 5w30.

 

now on amsoil.. dunno can anot.. will prolly bring some spare along the way...

[Theatreofdreams]

probably what you could have done is to increase your throttle first to bring up the rpm before downshifting (activating "O/D OFF"). the point is to increase the engine revolutions despite no significant increase in your travelling speed. (well, if there is sufficient acceleration at this gear then there isn't the need to downshift in the first place.)

 

i think with this, then there won't be such a drastic surge in the rpm, which explains the jerk/vibration.

[Qr25vet]

eh.. don't think I can answer you coz never travel at such a constant slow speed on NSH before

i travel constant speed of 90km/h from malacca back to SG leh...partly cos my gearbox ratio is too close

[Friendstar]

did 707 and grassland coaches overtake u like nobody's business at that speed?

[Friendstar]

Check your engine/transmission mounts for wear and tear. Even when your auto transmission downshifts and rpms spikes upwards to redline, although there will be some shift shock, there shouldn't be violent vibrations. However, when there is an abrupt change in rpms, the engine will rock forward or backwards depending on engine orientation, and if your mounts are worn, vibrations can be felt prominently.

 

my car 30+k only.... so fast wear and tear liao ah?

[Friendstar]

Check your engine/transmission mounts for wear and tear. Even when your auto transmission downshifts and rpms spikes upwards to redline, although there will be some shift shock, there shouldn't be violent vibrations. However, when there is an abrupt change in rpms, the engine will rock forward or backwards depending on engine orientation, and if your mounts are worn, vibrations can be felt prominently.

 

can u explain what is shift shock?

 

i think wat i felt is something like shift shock.

 

Violent Abrupt Shift Shock?

 

got such thing?

[Friendstar]

errr its my picnic hor...

[Jtis]

The shift shock is more like a single jerky sensation when downshifting, rather than the usual gear slurring that comes with normal driving. It defintiely won't be sustained vibrations.

[Friendstar]

will it damage the gearbox ah?

 

so far only happens twice

 

i hope my gearbox is still intact

 

I don't really understand why you have overdrive on when at cruising speed in the first place. Won't it be easier to drive without OD on, and then activate it when you wanna overtake (provided you are not already at your highest gear).

 

In any case I rarely use the OD function since I switch to steptronic whenever I wanna do fancy manouveurs. If I experienced a "clunk" like yours my heart would have definitely sunk as well

 

 

yo let's clear the air.

 

O/D ON means there's overdrive

--> means that ur highest gear can be engaged

--> means lower RPM for higher speed

--> that is good for FC plus cruising

 

O/D OFF means there's NO overdrive

--> means only ur 2nd highest gear can be engaged (for a auto4speed... that is ur 3rd gear)

--> means higher RPM for higher speed

--> bad for FC + cruising but good for overtaking with extra RPM oomph

[Friendstar]

yes!!!

i felt that

 

single VIOLENT jerk sensation

 

 

i never experienced any vibrations

 

its the one time thing.

[Boyboy]

alamak. just floor the accelerator hard when u wanna overtake. should be smoother. u press O/D, macam "force" the gearbox (note that even if u shift to lower gear, the gearbox has protective mechanism to prevent downshift if ur speed is too high) to downshift.

 

give the accelerator a hard poke and it should downshift to 3rd. otherwise, high chance that u are at peak torque for 4th gear liao.

[Jtis]

Chey.... Yes, shift shock... I bet you only maintain same foot pressure on the accelerator while you switch off OD right? Then when the autotrans 3rd gear engages, the gearbox had to instantly drag the engine rpms upwards to match its current geartrain speed. It is a little bit like downshifting in a manual car, without rev matching, and throwing the clutch at the smae time. Next time, flooring it is a better idea than switching off OD.

[Carcraze]

will it damage the gearbox ah?

 

so far only happens twice

 

i hope my gearbox is still intact

 

I don't really understand why you have overdrive on when at cruising speed in the first place. Won't it be easier to drive without OD on, and then activate it (activating it is basically to turn it off) when you wanna overtake (provided you are not already at your highest gear).

 

In any case I rarely use the OD function since I switch to steptronic whenever I wanna do fancy manouveurs. If I experienced a "clunk" like yours my heart would have definitely sunk as well

 

O/D On is the norm. When you press the button, it is to switch it off and that's when the gearbox will usually drop a gear if necessary or simply hold on to a gear longer before it upshifts. Therefore the norm is to drive in O/D On mode (default) which is also a more economical mode.

 

Don't get confused.

Edited December 11, 2008 by Carcraze

[Dafansu]

did 707 and grassland coaches overtake u like nobody's business at that speed?

 

my last trip to genting, the coach was at a constant speed of about 110.

[Nkps]

will it damage the gearbox ah?

 

so far only happens twice

 

i hope my gearbox is still intact

 

err... sorry OT abit here, so did you manage to find the X-RAY machine at Singapore Custom that to check on the fuel level of car?

 

[Nkps]

do you notice that those coaches' speedo meter is at MAX of 120km/h only?

[Dafansu]

this i never notice, but i'm using my gps to detect their average speed