Technical Grinding in Neutral After Chainging Drive Shaft

[SailorBob]

2010 Fiat Ducato x250 Multijet 120 2.3L with 6 speed manual

Summary: I replaced the outer CV joint on the driver's side and now there is a grinding noise in neutral that goes away when I press in the clutch, and I can't put the vehicle in gear at all. It drove fine for about 20 feet before this started. Now for the details.

So I removed the driver's side drive shaft to replace the outer CV joint. Wasn't sure how to remove the gear oil drain plug, but quite a bit of oil came out the driveshaft hole. Refitted the drive shaft, but wasn't sure where to refill the oil. Removed the battery box looking for refill / breather hole but only saw what looked like shifter linkages? Finally found it on top of the gear next to what I assume is the transmission speed sensor and engine mount. Manual calls for 2.7 liters 75-w85 GL-4 oil when fully drained. Everything I read said 75w-90 could be used safely. Filled with 2.5 liters ( since I figured there would be residual oil ) of Castrol Syntrax Universal Plus 75w-90 rated GL-4 / GL-5 / MT-1 supposedly safe for gears requiring GL-4:

Castrol Syntrax Universal Plus 75W-90 is a full synthetic multipurpose manual transmission and final drive lubricant. It
may be used in synchronised manual transmssions and final drives/differentials of a wide range of vehicles
(commercial vehicle, construction equipment, passenger cars) where API GL-4 or API GL-5 fluids are required and it
carries a number of approvals.

​

I replaced the battery box, started the vehicle, put it in reverse and drove about 15 feet. Then drove forward about 5 feet, put it back in reverse and then started hearing the grinding, and it wouldn't go into gear. Stopped the engine figured I didn't put enough oil in and added another 350 ml about. Restarted and noticed it was giving that mild grinding noise even though it was in neutral. Stopped engine, played with the shifter a little and after restarting no noise. But when I tried to put it in gear again the mild grinding started again, even in neutral, but goes away when I press down the clutch.

So I'm a bit confounded here. I can think of two possibilities, but no idea which might actually be right:

1. It drove 20 feet because the old oil was still stuck to everything but once the new oil started circulating the synchronizes stopped working properly because it's the wrong oil. Not sure why that would cause grinding in neutral.
2. Drive shaft wasn't quite in all the way and somehow popped out of place inside the gear . Why then no oil leaking from shaft hole? Why would that cause grinding in neutral?

The grinding in neutral is really weird. I assume it's constant mesh and so everything is rotating even in neutral but what could be grinding?

 

[sumpplug]

Hya Bob,
Is it possible you have disturbed a gear linkage when looking for a filler plug,
Just a thought hope get sorted quickly.

Eric

 

[sumpplug]

Sorry Bob,
Did'nt explain myself very well there, i meant is it possible some you have moved and replaced is fouling on the gear linkage and trying to engage a gear,

As you say when you press clutch down the stops,

Hope that was a bit more sensible ?

 

[SailorBob]

Here's a video of the linkage going through gears 1 - 6

https://youtu.be/ecOR6WSwr9g

 

[cris1117]

My guess would be drive shaft not fully home in gearbox.
You may not lose oil until its almost all the way out seen this before, I would strip out the bottom arm and give the hub a good tug to make sure the shaft is clicked fully in.

 

[SailorBob]

Here's a pic of where the driveshaft enters the gearbox:

 

[jackwhoo]

Anyone else surprised by the very wobbly selector shaft in the video?

When looking for a fill point did you remove any other bolts trying to find it? Are you 100% certain the fill point you found was a fill point rather than an internal component retaining bolt?

Drive shaft suggestion given sounds plausible , does the insertion depth into gearbox look similar to side not removed?

If you can get some help and possible: engine off, select any gear, clutch pedal down , hand brake off- can van be pushed?
If not clutch may not be releasing.

 

[SailorBob]

I also thought that I might have put oil in wrong place, but I'm pretty sure it's correct, you can see it's the black plastic breather cap were one adds oil on this model, same as what's listed in the Ducato CD manual. The vehicle can be pushed around in neutral, haven't tried it in gear, why would that make a difference? I would think in gear it would be extremely difficult to push it around because you're basically having to rotate the engine also... If the shaft isn't in all the way then the differential won't transmit the rotation to the gears and engine so it'll still be "easy" to push around? Is that it?

 

[SailorBob]

Anyone else surprised by the very wobbly selector shaft in the video?

Vehicle has 400,000 km on it, and I'm pretty sure by the look of the gear oil it hadn't been changed in a **very** long time. Not sure if that's relevant to the shifter though...

 

[jackwhoo]

engine off, select any gear, clutch pedal held down , hand brake off- can van be pushed?

If van hard to push or can not be pushed clutch may not be releasing.

 

[cris1117]

You're getting very sidetracked, if all was o.k before you removed the driveshaft then the driveshaft hasn't been correctly re-fitted
Forget the oil it wouldn't make a difference not for a long while anyway.
Not very familiar with the Ducato does the driveshaft have a retaining circlip on the end that enters the gearbox, is it still intact.

 

[SailorBob]

So I jacked up the truck and the first thing I'll note for clarity, the side with the wheel off ( the driver's side ) is the side I did the work on. During all these tests, only the driver's side spun, the passenger side never showed any movement.

So first of all this first video kind of shows the problem, with me letting off the clutch and you can hear the grinding:

Grinding in Neutral

Then I unscrew the driveshaft / axle nut and give it a few good wacks to try and push the shaft in a bit. I'd note there is no noticable change in how far in the shaft is, yet after this the drive's side shaft starts turning smoothly in neutral, first and reverse:

Shaft Moving OK after Getting Wacked

I'll note again that only the driver's side axle moves, the passenger side axle never moves. Then I did the test again and it started grinding when I put it in reverse:

Grinding in Reverse

In general, I found unscrewing the nut and smacking the shaft in about 10 times would temporarily make the driver's side shaft respond properly while at the same time the passenger side shaft wouldn't turn at all. There is no visible change I can noticed in how far in the shaft is after I smack it.

I'm not sure if this makes things more or less confusing...

 

[Anthony489]

Hi Sailorbob

I'm not sure I have the answer to your noise, but the following might shed some light. Apologies if you have already worked this all out.

With the clutch depressed, as long as it's releasing fully there will be no gear motion in the gearbox (it might take a second or two to slow and stop) therefore nothing to make a noise.

With the clutch engaged and in neutral, the gear pairs will all be turning (constant mesh) but the dogs will not allow any solid drive to the final drive pinion and crownwheel. However, there may be some oil drag, so if there is low enough friction in the inner seals, the hubs and the brakes the crownwheel may still turn with the vehicle jacked up. It is a simple open differential, so if one side has more friction then the hub will not turn but the other side will. The oil drag should be so small that the turning can be stopped by hand pressure, but go careful and wear gloves if you test this. If it can't easily be stopped then you have solid drive which indicates an abnormality.


With the clutch engaged and in gear, you have solid drive via dogs to the pinion and crownwheel. Again, with the vehicle jacked up you will see the nearside, the offside or maybe both hubs turning. This is quite normal. Which side turns will depend on the friction in the inner seals, the hubs and the brakes. These are unlikely to be the same both sides, and could change depending on how the driveshaft is fitted.

Difficulty with gear engagement is normally due to a dragging clutch (not fully releasing) or a problem with the gear linkage. The clutch is unlikely to have changed during this work. As others have said, it possible the linkage has been disturbed during this work. However, your video doesn't show anything jammed, just rather a lot of sideways play in the selector.

The noise is a puzzle, I assume it's coming from inside the gearbox. I fear that something metallic has been disturbed during the oil change process and has come to rest where it shouldn't.

 

[jackwhoo]

Interesting videos.
Ignor my thoughts about inability to engage gear possibly caused by clutch drag.
From videos it looks like you can engage gears but get no drive .

 

[cris1117]

I think what may be happening here is a problem with the retaining circlip not depressing enough to allow the driveshaft to fully engage with the internal gearing of the crown wheel hence the grinding.

When you hit the drive shaft it engages but slips back out because the retaining clip hasn't engaged hence the grinding on the crow wheel.

The easiest way to check this is to try to pull the driveshaft out if it comes out easily then the retaining clip isn't engaged in its groove.


If you don't have the correct tool I found the easiest way to depress the circlip is, push the driveshaft in by hand then use two pairs of mole grips on the drive shaft placed so you can use foot pressure on the shaft push and wiggle the shaft at the same time until you hear the click of the circlip dropping in, once in you should not be able to pull it out by hand.

 

[cris1117]

Just to clarify you wont engage the driveshaft by just hitting it it will just bounce against the retaining clip, you need constant pressure to force the clip to contract slip in and then expand into place in the gearbox bearing.
If you imagine the housing is like a funnel shape and as you push the driveshaft in it compresses the retaining clip, at the other end of the funnel is a groove for the retaining clip to expand into and lock the shaft into place.

If you push the shaft in by hand or just hit it with a hammer it will feel like it is in but it will just be resting against the retaining clip it need to go another 5 mm in.

 

[Pugglt Auld Jock]

'Morning sailorbob, I'm feeling for you with this problem, very distressing. Ok, don't worry about the oil being the cause. You could drain the oil entirely and drive round the block and see very little effect. I'm not saying damage would not be done by either underfilling/overfilling or using the wrong oil but you just wouldn't notice any effect over such a short period of time.

People above have made many interesting suggestions but I'm finding myself drawn to the problem you seem to be having with the inner driveshaft joint. Can you tell us if it's properly locked into the diff now or, if you give it a good jerk can you pull it out by hand? If the circlip has properly engaged there's no way you'll shift it simply by hand.

As has been said above, with the gearbox in neutral and the clutch engaged (ie driving the box, pedal up) the gearbox internals will be rotating as the gear teeth themselves are in constant mesh. This is why I'm interested in whether the drive shaft is properly locked in place. I've seen, not often but more than once, the situation where the circlip on the inner joint becomes displaced and/or broken and either the whole clip or part of it falls inside the box - ouch! I'm interested in this particular aspect because the noises you're getting seem to me to indicate there may be a "foreigner" inside the box. Again not common, but also not unknown, is where an external "bolt" is mistaken for the drain/fill plug and slackened instead causing an internal part of the box to drop off - any possibility you've done that?

I think a good place to start would be to whip that shaft out again and have a careful look at the circlip just to be sure it's intact and not the problem. - Good Luck.

 

[Pugglt Auld Jock]

Anyone else surprised by the very wobbly selector shaft in the video?

Drive shaft suggestion given sounds plausible , does the insertion depth into gearbox look similar to side not removed?

Aye Jack, strangely "wobbly " isn't it? But i don't know this 'box, maybe they're all like that?

Looking at the picture posted of the driveshaft where it enters the box. It doesn't look fully home to me and I fancy I can see a bright polished surface on the shaft where the seal would be contacting it if it were further in?

 

[Pugglt Auld Jock]

SailorBob. Just another thought, and it's difficult doing this "diagnostics from a distance" thing, but I'm wondering. If the circlip, or just a wee bit of it, has broken off and been "chased" into the 'box by the shaft as you were inserting it then it'll have ended up inside the differential spider gear casing. I notice your noise seems to come and go a bit and it occurs to me that if it's "mixing it" with the spider gears then the noise would only be there when one wheel/hub is turning at a different rate to the other. You'll have noticed with both wheels up in the air there is a tendency for one wheel to turn but not the other or for one wheel to turn faster than the other which will result in the spider gears turning inside the diff. With the engine running, gearbox in neutral and your foot off the clutch so the gears in the 'box are turning put your foot on the brake which will stop both front wheels turning. So now the driveshafts, diff spider gears, crownwheel and pinion will all be stationary. Still got the noise? If the noise gets a lot louder when you do this then maybe the inner joint isn't fully home and the splines are "riding" against eachother? If the noise doesn't alter at all at least you know the problem is probably with the gear cluster itself? If so you're probably going to have to take the box out so you'll be able to see if there's a clutch problem at the same time, but it doesn't sound like clutch to me and I can't imagine what you might have done to suddenly get a clutch problem doing what you've done (no chance you dropped something inside the bell housing - not the "right" sort of "tinkly" noise for that though I fancy)

 

[jackwhoo]

Another thought, are you 100 % sure the new cv joint is correctly fitted/locked on to the drive shaft ? If the splines of drive shaft are not fully inserted into cv joint problems ensue. Plus is new cv joint correct part if splined hole inside cv joint is too large the splines will strip off and there will be no drive- drive shaft will rotate inside cv joint wheels won't turn.