Technical T-Jet reverse gear crunching and difficult to engage.

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Technical T-Jet reverse gear crunching and difficult to engage.

jameshobiecat

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Reverse gear in my T-Jet crunches loudly almost every time I engage it, and sometimes does not want to engage at all. Occasionally it feels like it has engaged, but it has not, this results in a horrific grinding of gears as the clutch is released. It’s getting really embarrassing and is beyond a joke.

I have read other posts on here saying that 5 speed GPs do crunch and that you need to give it 2 seconds before engaging reverse but his does not work. I have tried everything, letting the clutch out in neutral before selecting reverse, going into 1st gear then reverse, mashing the clutch pedal into the floor very hard etc. The thing even crunches when selecting reverse from a standing start i.e. without having even gone into any forward gears. I have taken to starting the car in reverse with the clutch depressed when I know it’s the first gear I require.

Whilst the crunch is annoying, it is the reluctance to go into gear that worries me most.

Has anyone else suffered this reluctance to get reverse on their T-Jet? What was the cure? Has adjusting the gear selector cables worked for anyone or is it more serious than that?

P.S. The clutch feels fine; it still bites nice and low in the travel, feels light and does not slip. No other gears are difficult to engage. Car has done only 27k miles.

Regards, James
 
I'd say that the fact the clutch bite is low indicates that the drive isnt being removed from the gearbox fully. Check the free play at the clutch pedal is present, from memory it should be about an inch or so, my GP's clutch bite was always about 66% of upward travel.
 
Reverse gear in my T-Jet crunches loudly almost every time I engage it, and sometimes does not want to engage at all. Occasionally it feels like it has engaged, but it has not, this results in a horrific grinding of gears as the clutch is released. It’s getting really embarrassing and is beyond a joke.

I have read other posts on here saying that 5 speed GPs do crunch and that you need to give it 2 seconds before engaging reverse but his does not work. I have tried everything, letting the clutch out in neutral before selecting reverse, going into 1st gear then reverse, mashing the clutch pedal into the floor very hard etc. The thing even crunches when selecting reverse from a standing start i.e. without having even gone into any forward gears. I have taken to starting the car in reverse with the clutch depressed when I know it’s the first gear I require.

Whilst the crunch is annoying, it is the reluctance to go into gear that worries me most.

Has anyone else suffered this reluctance to get reverse on their T-Jet? What was the cure? Has adjusting the gear selector cables worked for anyone or is it more serious than that?

P.S. The clutch feels fine; it still bites nice and low in the travel, feels light and does not slip. No other gears are difficult to engage. Car has done only 27k miles.

Regards, James

Same with mine but it's intermittent, think it's half to do with what lateral angle the car's parked at as it likes to crunch while I'm on my drive (a bit of an incline).. clutch fully depressed trying to reverse out of the drive it sometimes crunches and takes a good 3-4 tries to get it in reverse, even after engaging 1st.

I always assumed it was the same on all GP gearboxes :confused:
 
Never had any issues with the clutch on my MJet. I'd still check the clutch pedal free play & adjust if required, probably worth looking at what the cables are doing at the same time but I dont have any experience of adjusting them sorry.... otherwise the intermittent nature of the problem may be a concern maybe pointing at the release fork mechanism or the release bearing, either way both the latter require removal of the gearbag.
 
My reverse crunches almost every time as well. No rhyme nor reason to it, everything else seems fine (bar an occassional horrendous judder in reverse if you don't give it enough gas).
 
The Tjets have a clutch unique to them, with a self-adjusting cover plate that maintains the same pedal height and biting point throughout the life of the friction plate.

I always found it to take a fraction longer to 'spin down' and would result in some mild graunching if selecting reverse too quickly after dipping the pedal. I also remember the biting point being slightly higher than 'normal' clutch's.
 
Reverse gear has no synchro that's why.

I also experience the crunch or disengagement but if I select 1st gear and then go into the reverse it's ok (although sometimes I forget it :p),as the gears get synchronised.

Strange it doesn't work for you though...
 
Reverse gear has no synchro that's why.

The only 'common' gearbox with a synchro on reverse is Ford's MTX75. Most manufacturers don't bother, but that's not the point I was getting at- the crunching can happen in any GP 'box if selection is rushed, but the Tjet is more susceptible to it and more patience is needed.

If it's still doing it after waiting several seconds, then there's some drag on the clutch, whether it's air in the system (or a leaky master/slave cyl) or a faulty/worn clutch.
 
I appreciate that the 5 speed has no syncro on reverse; I believe from old posts on here that the 6 speed GP gearboxes do have one so M-jets etc are not affected by the crunch. But that it crunches when selecting reverse from a stand still is puzzling.

Lots of people suggesting that the clutch is not dis-engaging fully, I’m not convinced that there is anything wrong with the clutch because it feels great in normal driving. Is there any way I can test this? Perhaps I could get the front wheels up in the air on axle stands and select a gear, press the clutch and see how easy it is to stop the wheels spinning. To clarify; when I said the clutch was 'still biting nice and low' what I meant was that it is normal, not biting right at the top of the travel.

As I said in my original post, it is the occasional reluctance to engage reverse that bothers me most, any ideas on this? I have noticed that if I apply pressure to the gear stick as I let the clutch up, I can feel it ‘pop’ into gear which suggests that it might just be that the gears are not aligned. It is odd that the going into 1st trick does not always work. I have never had a car with these quirks before, but then I have always driven much bigger and higher spec cars which I presume had a reverse syncro. I could stick my previous 407 in reverse when traveling forwards at about 10mph with no problems (not that I made a habit of this, but it could be done).
 
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Reverse will crunch when standing still as even in neutral, the drag on the input shaft means the gears will still be rotating with the clutch released, and will still take a little while to slow down once the pedal is pressed.

It's not unusual (in any gearbox without a reverse synchro) for the reverse gear teeth to not fully mesh and need some pressure on the lever while slightly lifting the pedal to allow them to rotate into place.
 
Sometimes mine doesn't want to go in, but it always does on the second go. Never seems to be any pattern to it either.
 
Sounds like mine is no worse than many others, i'll just have to get used to it. Fiat cost cutting strikes again!
 
Sounds like mine is no worse than many others, I'll just have to get used to it. Fiat cost cutting strikes again!

Another view point on this is that all the issues you have described are normal behaviour for most cars. It sounds like you have got used to cars with a syncromesh reverse, which is less usual than cars without. The T-Jet gearbox is actually a C510 gearbox designed in the mid 80s and used extensively on FIATs and Alfa Romeos in the 90s and 00s, not a modern cost-cutting experiment. The modern versions of the box are much better than the early versions of this box, but clearly peoples expectations of vehicles and their ease of piloting have rocketed in recent times.

You need to be a little more mechanically sympathetic to engage the reverse reliably. With the reverse gear being straight cut and without syncromesh, the gearbox shafts should be still or turning very, very slowly before engagement. If you are unlucky, the top of the teeth on the input shaft and the teeth on the reverse gear will hit each other, rather than slotting together nicely. This is simply chance. You will feel this in the gearstick as it will feel like it hasn't moved far enough to be properly "in". There is no point in trying to move then. You have three choices:

(1) Pull on the stick hard to try to force the meshing of the gears. This is a bit brutal and often doesn't work.
(2) If you are on even the slightest incline, allow the car to roll either forward or backward the tiniest amount whilst lightly pulling on the gearstick. The clutch is down all this time of course. The movement of the car slightly turns the input shaft and allows the gears to mesh by changing the relative position the gears were in. This works very reliably.
(3) Quickly let the clutch pedal up and put back down again. Gives you a second chance on the fruit machine that is the reverse gears. Does the same as (2), but takes a little longer as you have to wait for the box to spin down again before trying. You may also be unlucky and have the same situation again.

These are all tricks that either have been lost over the years or never learnt in the first place. You can take the art of a reverse change to another level by anticipating the issue. When bay parking at the supermarket, you pull up at say 45 degrees in front of the space. Dip the clutch as you brake and just as you come to a stop, select reverse. You will actually feel the gears lightly tapping each other once or twice before effortlessly engaging with minimal stick force. This probably all sounds like a right palaver, but like all things, it can become effortless and normal with practice.
 
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