Technical reverse grinding noise - damage?

[ruinin]

I understand why I have to wait about two secs before I engage the reverse gear, but say once a month I forget and do it too quickly - noisy... Just I want to ask if I do some serious damage to the transmission if I make this mistake once a month or so...

 

[jrkitching]

I understand why I have to wait about two secs before I engage the reverse gear, but say once a month I forget and do it too quickly - noisy... Just I want to ask if I do some serious damage to the transmission if I make this mistake once a month or so...

It's not going to do it any good.

In the worst case, you could chip a tooth; if the fragment then gets lodged elsewhere in the geartrain, you could be looking at a wrecked gearbox. Not likely perhaps, but certainly possible.

It has happened before on a brand new car; the damage was likely done during delivery.

 

[DaveMcT]

Reverse has no synchromesh so just treat it gently. Let the revs drop in neutral before engaging reverse. Otherwise the spinning input shaft will hit the static secondary shaft and crunch!

 

[CCTG]

I Put mine in 1st then into reverse. That seems to stop any grinding

 

[DaveMcT]

I Put mine in 1st then into reverse. That seems to stop any grinding

Good point. When 1st has a sticky synchro, going for 2nd then to 1st will engage 1st quietly. So a great idea for selecting reverse.

 

[jrkitching]

You'll notice this more when the engine is cold, because the idle speed will be higher.

If your first move of the day will be going backwards, there is some merit in selecting reverse before starting the engine (with the clutch depressed, obviously).

 

[DaveMcT]

I had a 900cc 90+ bhp bike that always crashed really badly into 1st gear. Bikes don't have synchro on any gears and most have a multi plate wet clutch that drags when cold. Starting in gear (with clutch pulled) solved the gear crashing and I could feel it twitch as the clutch plates let go.

Bikes have smaller batteries so easier to run flat, but I never had battery or starter problems. The bike had done 75,000 when sold.

So what's all that about? Get into the habit of putting the clutch down when starting the engine and if you need reverse select the gear before turning the key. the extra starting load wont upset the starter or the battery.

 

[SB1500]

This happens me too. Thanks for sharing the tip of 1st > Reverse.

Are all gearboxes the same?!
And is this just as likely to happen on a brand new Panda/500 too if you're 'too quick' on the selector?

I know when my sister owned my Panda for 2013-2015 she drove it like a bloody 4x4 and thrashed it.. I always attributed my crunching issue with that type of neglect. Maybe I'm wrong!

In 2013 when I drove my Panda as a learner, I noticed how short the gear selector felt and how precise it was. Not the same story when I first drove it as my own last October!

 

[DaveMcT]

Wear in the selector mechanism is entirely separate from wear in the gearbox itself.

The best way to have a long gearbox life is to match the revs as if there's no synchromesh. I mean fairly quick upshifts so the engine revs don't drop between gears and throttle blip on downshifts so the revs rise to see the next lower gear.

Slow "gentle" gearshifts can really work the synchromesh. I means output shaft is doing 40 mph input shaft has dropped to tikover. Driver then bangs it into the next cog and the synchro has to match the input and output shaft revs so the gears can actually connect.

Wear in the selector system is just plain wear and tear. You could fit a new lever box and maybe adjust the cables. Selector wear at the gearbox end is less of an issue as its all running in oil.

 

[SB1500]

DaveMcT interesting. So you say slip it into gear rather quickly without letting revs drop to maintain a good gearbox?

My car is how it is, but I'm very interested for any new car I buy in the future.

Driving habit seems to be a lot to do with how cars age

 

[DaveMcT]

When the revs are matched the gears will connect nicely with or without synchromesh. Synchro allows lazy drivers to get away with all sorts of abuse. Or rather, what would be abuse with a crash box is now ok.

It's not about slamming the gears in or dropping the clutch. When you throttle off to shift up, the revs drop naturally. So shift quickly to match the revs. Shift slowly and the revs will have dropped.

Going down a gear, mismatch the clutch and throttle so the revs blip and shift a fraction after while the revs are up. Most people shift down slowly. Sometimes, you'll see the car lurch especially on hills as the forward momentum pulls the engine revs up to speed.

 

[SPORTPACK50]

Anyone still double-declutch or indulge in a bit of heeling and toeing when enjoying a winding country road?

 

[jrkitching]

Anyone still double-declutch or indulge in a bit of heeling and toeing when enjoying a winding country road?

Shortly after passing my driving test, I got a summer job as a van driver with the local greengrocer wholesalers. As well as the vans, they had a fleet of Bedford TK's. One had been built as a superlightweight curtainsider and could (just) legally be driven on a car licence; they used it to train new HGV drivers. They promised me they'd teach me to drive it sometime before leaving for university. Well, late afternoon on my second day, there was an urgent delivery to go to Sainsburys and the only driver & vehicle left in the place was me & the wretched TK, so despite my protests I was sent out unsupervised with it. The beast had a crash gearbox & I'll swear it had been designed to be driven by a gorilla; I can still remember crunching my way through the Cambridge rush hour and just how I managed to get there & back in one piece I'll never know. It was also the first thing I'd ever driven with airbrakes and nobody had told me never to apply the handbrake unless you're stationary, so I very nearly got rear-ended at the first set of lights as I came to an abrupt halt well short of the stop line.

 

[DaveMcT]

Anyone still double-declutch or indulge in a bit of heeling and toeing when enjoying a winding country road?

I don't double declutch but always mismatch the revs on downshifts. Down shifts are usually quicker than upshifts. The Selespeed Alfa 156 was really great that!

I learned to drive on the site Landrover (Series II LWB diesel) with crash on 1st and 2nd and decidedly reluctant synchro on 3rd and 4th. The most fun was the coal stock earth scrapers. Four wheels, hinge in the middle steering and a howling Detroit 2 stroke with another driving the back wheels. Fully loaded it carried 40 cubic yards of coal - probably 60 to 80 tons pay load. Semi auto gears so no worries with clutches and rev matching.