ZF gearboxes

Scania N113CRB luver SG · 2006-10-15T01:10:48+00:00

Oh by the way, correct me if im wrong. The rear axles used on the Citaros are mand by ZF, known as the ZF portal axles.

Scania N113CRB luver SG

Anyone noticed that some ZFs lock-up on the first gear, as well as the second gear in some models(all lances)? And also anyone notice that some gearboxes has a psst psst psst....... sound? Similar to the SBSTransit 0405 mercedes gearboxes? Although the mercedes gearbox one can be heard very loud, ZFs can be heard too! Anyone can tell me why? Izzit because of the retarder? Please ! I would really like to know! Very Happy

stooper SG

What "psst psst" sound? It is like air releasing? I haven't noticed it yet.

Scania N113CRB luver SG

Im not too sure. Notice it carefully, when it changes from 4th to 3rd gear for example, it will have a psst sound. I think it is the retarder at work. When it switches to neutral, it can be heard more clearly. Confirmed not the brakes! The Dennis lances, some LO, some VO3x, some SMRT 0405/0405g had the same sounds! Rolling Eyes

Windy_hates_B10TLs SG

This would be the air escaping the retarder system as air is built up to slow the bus down. The retarders are magnets which use a forcefield to slow the engine rpm down. It comes down to variances in gearbox build, some ZFs howl, some don’t. I have programmed ZF gearboxes to lock up or not lock up, and alter shift points (ie, what engine rpm to kick up a gear).

Scania N113CRB luver SG

Air? I thought i uses hydraulics? I thought it is a hydraulic retarder. Anyway thanks for the information! Very Happy I realised that some SMRT Volgren 0405 had been programmed to have no gear lock-ups, is dat true?

Scania N113CRB luver SG

ya. the howling can be heard on the SMRT Volgren 0405, especially when it shifts from 4th to 3rd gear. Sometimes very loud.

SBS9828X SG

windy are u some kind of mechanic or engineer?

stooper SG

What do you mean by lock up and not lock up? Is it something to do with why some buses like SBS Merc sound like they have 4 gears but only have 3?

^tamago^ SG

indeed.

though the underlying principle behind SBS Merc gearbox is not about torque convertor lock-ups but rather slip gears.

stooper SG

Hmm... What's the differences in slip gears and lock ups then? Confused

SBS3625D SG

Yes, and some 0405 Hispano, and maybe some VO3X, although the VO3X one is positively irritating.

Windy_hates_B10TLs SG

I am a recruitment consultant. I do part time work at a bus company.

Windy_hates_B10TLs SG

WRONG

The Mercedes W3E gearbox's jerkiness is the result of torque convertor lock ups.

Scania N113CRB luver SG

i think the SMRT’s L113CRLs has the loudest gear lock-up whining sound in SMRT fleet! Everytime near my house when CRL passes by i can straight away tell that it is the CRL. It is very distinctive! The VO3x and LO3x is even louder!

Scania N113CRB luver SG

Erm does anyone here prefers ZFs over Voiths?

jetabt767400 SG

No real preference.
But the psst sound, heard before many times, and it goes...
wooooo... (braking), psst!, wooo (then normally will have 'dung' sound as the brakes take larger effect), then psst! brake sound, stop.
Diff ppl got diff sound hor, disclaimer...

jetabt767400 SG

Ya, then the SMRT 0405, gear hub-reduct sound most loud and horrible as I saw...
eeerrrooor, emmmmMMMM(rev 1700-2000rpm), BRI-AO!, deeeee... then it will almost miss a gear and goes 'dung' again to get back to a lower gear.
Some sound treatment eh, I love 0405 sounds!

jetabt767400 SG

Voith on 0405G almost kills the signature sounds that ZF had for these Mercedes pals.
Hub reduct on Voith would just mean...
vroooom, VROOOOOOOOM!, vroooooooommmmm and so on...
ZF, diff story.
erooooorrrr, eeeeeemmmmMMBRI-AO!, errrrooooooorrr....
At least there is that sound!

Scania N113CRB luver SG

Ya this is what i meant, i like this sound especially on the LO3x, very distinctive!
I also like it on the O405G Box. I like it especially on the Volgren 0405 rigid. Air-con very quiet, so can here the drone sound and the "weeeeeeeeoooorrrrr" sound! Mr. Green I love ZFs!

The_Bus_Guide SG

All O405s have the same hub-reduction from Mercedes. Hub-reduction is a set of planetary gears located inside the rear axle. Its purpose is to further reduce the number of revolutions coming from rear differential, thus increasing torque. Nothing to do with the gearbox at all. And they definitely don't make such noises stated above.