Got a drive train issue with my T-Jet and looking for some advice.

Coming home yesterday onto a roundabout, I started getting a rotational clunk that could be felt through steering and floor. Happens when in gear under throttle or when coasting with clutch engaged in any gear and has a sort of sprung feeling to it if that makes any sense? Noise / clunk is regular.

Jacked up front end, both wheels spin free, smoothly and quietly in neutral and in gear they spin the same but in opposite directions as would be expected and this is the case at any steering angle.

I started the car on stands and engaged first gear. As I brought the clutch up and the wheels began to turn there was sort of grinding noise and the engine sort of lurched a little on its mountings, this is what I was feeling on the road. Same in second gear but slightly worse.

No issue with engine, no prior issues relating to clutch or gearbox no visible issues that I could see. Driveshafts have little or no play and no sign of any oil or grease where it should not be.

Car has just hit 63,000 miles and passed MOT yesterday with no issues!

Anyone got any thoughts, I'm thinking possibly clutch plate or dmf?

Cheers

Ben

Hmm! So sorry to hear of your problems. Always difficult without hearing/seeing/feeling the symptoms but my first response would be not clutch or DMF. Even at idle engine is going around 1000rpm so this would be a much higher frequency thing, much higher than you describe. Anyway, DMF's more ussualy rattle and clonk whilst giving a "different" feel to the pedal action. So far I've not met one that shook the steering?

From what you've tried already it would seem that the drive shafts, wheel bearings and output side of the box are probably ok although none of your tests put any real load on anything so may be misleading. I would try putting it in gear without the engine running and either get someone to hold the clutch pedal down or use a rod to hold the clutch pedal depressed while you rotate the road wheels. Because of the way the differential works you need to rotate both wheels in the same direction if you have both wheels off the ground or just one wheel if only one wheel is suspended. As you do this you will be rotating all components in the box including the input shaft and clutch driven (friction) plate. If you do it with just one wheel off the ground you will also be rotating the diff spur gears. Because the engine isn't running you should be able to isolate where the noise is coming from more accurately. Please don't get under the car if you're only supporting it on the jack, will you?

I have had "jumping" effects like this when a foreign body, maybe a piece of chipped gear tooth or part of a collapsed bearing is jumping around and getting between the gear teeth. If this is the case the "bits" may lie in hiding in the bottom of the box at very slow speeds of rotation, but being picked up and circulated by the flow of oil when rotational speeds increase.

So my "stab in the dark" would be an internal gearbox problem, possibly a bearing problem on the 1st motion shaft/input side of the box. If so you'll need to do a very careful check of all components for damage, especially other bearings which may have " ingested" bits of metal before a rebuild is undertaken. The obvious thing to do would be a visit to the scrappy and just fit another box. Whatever, it doesn't sound as if you should risk driving it because if it's making noises like this it's liable to let you down sooner rather than later.

Substantial amounts of dosh involved here so, if you're not certain get someone who "knows" to give it the once over before diving in. Again my sympathy and commiserations. Good luck. Jock.

Thanks Jock,

Hoping it's not a gearbox, C510's are not cheap! I've had a c514 box go in my other Punto and there was whining etc prior to anything serious happening. There was no warning here, fine coming up to roundabout, when on roundabout and picking up speed the issue started.
I'd not been booting it, rarely do.

This is is present from crawling speed, i.e, pulling out of my garage on to the drive when rotational speeds will be very low.

Cheers

Ben

Just another wee thought - inner driveshaft joints? Regards Jock

Fascinated to know the outcome. Do let us know won't you? Regards J.

A breaking up inner joint could certainly cause the jumping and steering effects. Hope, for your sake, it's not the box! J.

My first thought => drive shafts.
-Have you lowered it?
-Does it do it only when accelerating?
-is it more pronounced while accelerating?
-how does it behave while engine braking?
-Does the clunking stop if you are just costing in neutral?(describe)-clutch pressed
-Does the clunking stop if you are just costing in neutral?(describe)-clutch depressed
-Describe costing in gear clutch depressed (pressing the accelerator pedal just enough not to engine brake)
More pronounced in turns?

Hi Aurick,

It's lowered by about 15mm from standard T-Jet height, been that way for approximately 3000 miles.

Does it in any gear (certainly 1,2,3 as I was almost home when it started and didn't need another gear), also in reverse. Didn't really engine brake in the distance I traveled. Happens when crawling along in gear (minimal throttle), also when accelerating but not sure it is any worse. Also happens when coasting in gear with clutch depressed and steering position makes no difference.

Any thoughts?


Cheers

Ben

Ben D said:

Hi Aurick,

Any thoughts?

Click to expand...

Yah... check the drive shafts (probably the left and side one)

GP T-jet drive shaft are known for popping put from the inner joint (the tripod cup), especially if lowered... add to that some suspension compression during cornering.
I'd say it might have come out for a fraction of a second and might have pooped out some of the cylindrical bearings on the tripod.

It might still be in the boot, the boot might still be in perfect condition.
-Drain the gearbox ( pay attention to metal bits/flakes/shavings etc) necessary for next step:
-Remove the drive shafts (have someAmazon.co.uk: Red Line RED80401 CV-2 Synthetic Grease for rebuilding .. if can still be saved)
Even if one of the drive shats needs replacing.. you can regease the other one while you're at it.
On the other side you would need to replace the drive shaft, or rebuild it with new tripod and cup.
These 2 steps should tell you where the problem is.

Ok, thanks, I'll have a look. All seemed ok spinning shafts through diff with both wheels off the ground, it only occurs under drive if it was the shaft my logic is that it would occur when rotating wheel?

Road I was on was when it happened was really flat and straight, could it still pop out in that situation? There are guys running lower without problems however if this is the case I'll swap out the springs for 5mm less drop.


Cheers

Ben

it's still possible: there's an immense between the forces you pun on to the shafts.. and what the engine puts through when moving the car.
+ different angles

Hey Ben, any news on this?

Not yet mate, I've not had chance to have a good look myself yet. Took it to a local garage and they could not identify it, they weren't need the impression it is brake related. I'm hoping to get a good look this coming weekend.

I think you're probably right about NS driveshaft inner joint although I really can't see how it would have happened.

Cheers

Ben

Hi Aurick,

Not going to get a chance to pull this to bits for a while. I'm thinking of just getting two new spider bearings and getting them fitted either by me or a local garage.

Do you know, by any chance, if I could access these and change by undoing strut from hub, splitting lower arm from hub and removing boot to pull shaft out from the cup or do I also need to remove the cups from transmission?


Cheers

Ben

Disconnecting the hub from strut and lower joint should give you enough movement to separate the inner jiont. Might not even have to split the joint.

Robert G8RPI.

Thanks Robert, I thought that may be the case but wanted an Idea of how much grief it was going to be prior to starting! Once separated is the spider bearing easy enough to change?


Cheers

Ben

Ben D said:

Hi Aurick,

Not going to get a chance to pull this to bits for a while. I'm thinking of just getting two new spider bearings and getting them fitted either by me or a local garage.

Do you know, by any chance, if I could access these and change by undoing strut from hub, splitting lower arm from hub and removing boot to pull shaft out from the cup or do I also need to remove the cups from transmission?


Cheers

Ben

Click to expand...

When i replaced the tropod on mine... i took out the strut completely, but lef the other bits in place.. had enough room.


But before doing anything:
Put it on jack stands get underneath.. and pull back the inner boot, should be pretty obvious if the problem is there.

As i remember it's held in by a torx/Philips screw.. then a few gentle hits with a hammer to get the old one off the splines.

Thanks Aurick, just going to order bearings for both sides and some grease. If I'm taking it to bits to check it out I'd be as well replacing them anyway and hopefully, it will be the issue. If not, at least the bearings will be fresh!

Cheers

So, stripped NS inner CV joint...... Looks brand new, all bearings in place and no sign of an issue. I have a new original birth tripod but I'm not going to fit is as it has plastic rather than metal shells.

Looking at it with boot off and rebuilt, it looks highly unlikely that it could come anywhere near the end of the cup even under full travel.

Back to the drawing board, any ideas of where to go from here?

Cheers

Ben