Transmission mount: Is it time to replace? (video)

[defever]

Hello forum users,

For the last year or so, I've been trying to figure out a rubber rubbing, knocking noise when turning at slow speed:

Added grinding noise only when turning left at slow speed - Page 2

I replaced steering tracking rod boots (N/S and O/S) and O/S both upper control arms. The noise sort of went away but it's back again and there's no consistent pattern to what causes it.

That led me to think maybe there's more than just control arms that's causing the noise. The noise is more apparent after the engine is warmed up.

I looked at all the control arms and the N/S both upper control arms need replacing (good amount of play and I can see that the bushings are cracked).

I also found this on the transmission mount (that smiley face bushing on N/S, 8D0399151H):



This needs replacing doesn't it?

My question is:

1. is this DIYable?
2. Whilst I attempt to replace the mount, is there anything else I can replace for preventative / maintenance measures?

I have two axles, enough ordinary ratchets and hand tools to undo most bolts and nuts. I'm comfortable getting under the car and exploring things.
I think I'll get a trolley jack to support the transmission.

Thanks very much in advance, as always!

[defever]

Okay, I did some homework and it seems that the transmission mounts are DIY-able. I got the two mounts ordered and hopefully the old ones will come out peacefully.

"How to" on replacing tranny mounts:

http://www.audiworld.com/forums/a4-b5-platform-discussion-1/transmission-mount-replacement-1-8t-304601/

Transmission mount replacement - B5 VW Passat and Audi | VW TDI forum, Audi, Porsche, and Chevy Cruze diesel forum

Also I'll try replacing the two N/S upper control arms too. I think I can also do this myself, the only concern is the knuckle joint bolt that is exposed to the element and likely to be seized pretty badly. I'll spray some penetrating oil regularly. There's a nice video from Bentley for upper arm replacement (A6 C5)!:



Also, I figured it's a good time to replace the engine mounts while the tranny mounts are replaced.

I did the motor mount test:



Although the engine doesn't knock or jerk, there is a fair amount of frontal movement (more than the KIA engine on the video), so I think the front snub mount also need replacing. The hydrolic engine motor mounts are not leaking, but it might have leaked completely already, I never checked these before. The faithful myturbodiesel website has the "how to" on this, but I think it's quite tricky to get the alignment?:

http://www.myturbodiesel.com/wiki/motor-mount-replacement-b5-vw-passat-tdi/

But as a practice to get the front of the car in service position, I might have a go on replacing the snub mount at the front:



One question regarding the replacement part brands: How good is Febi Bilstein?
I called up TPS for motor mounts and it's £76 for left and £96 for right (+VAT)! What brand do they usually supply? KMS Parts on eBay sells Febi / Meyle / and another brand I never heard of for less than £30!

Can these be trusted?

[defever]

Update with success (hoping that nothing falls apart)!

Replaced the N/S upper control arms. The knuckle joint bolt came out with little negotiation after couple of days of spraying penetrating oil. The strut came out quite smoothly and all the bolts were very cooperative. Whoever replaced the arms last must have treated the nuts and bolts with anti-cease; very very grateful of such a small effort.

The transmission mounts were very easy to replace as well; just followed the "how to" link above and raised the transmission slightly with the jack. Everything went back in very well.

The worn out N/S (left) tranny mount:



Completely torn apart inside. No wonder it was making that rubbery noise. Drove around for a bit after replacing the control arms and tranny mounts and there's definitely less added rubbery squeal/noise that I would hear normally.

There are still some more so I'm suspecting the engine mounts, and something involving the steering rack or column.

[defever]

Moving on to the engine mounts, this is the current state:

O/S (Right) mount:



N/S (Left) mount:



Front snub mount:



The O/S mount looks like it's been leaking and probably leaked everything. The N/S looks fine for now, but the rubber at the top has crack all around. The snub mount looks like its in perfect condition. I couldn't see any crack or signs or wear.

I tried to replace the side mounts but I couldn't really see how it could be done without raising the engine quite high to clear the long threads on the mount.

Questions:

• Is it easier to remove the mounts from the bottom at the mount bracket?
• Is there a nack to realign the bracket with the subframe and the engine?
• The O/S mount top nut is obscured by the turbo from the top: What is the easiest way to access this nut?

Thanks very much as always!

[mumutley]

Hi Well done

When replacing engine mounts I put the car up on axle stands or diy ramps
Then a block of wood on a jack under the sump of the engine
Do one side at a time
I cant remember how I did the engine mount under the turbo but it is certainly diy able

[defever]

Thanks very much mumutley,

When you did your engine mount, did you disconnect the front snub mount to allow the engine to be raised with the jack?

I think I might swing the sway bar and remove the mounts from the bottom by also removing the metal bracket holding the mounts and re align the bracket using the three wholes. I'm bit worried that by trying to raise the engine with a jack I might crack the oil pan (I have a wood block nearly the size of the pan).

Thanks again!

[defever]

Update: engine mounts replaced and the engine hasn't fallen for 20miles so far!

I ended up CAREFULLY lifting the engine from oil pan instead of fiddling with the mount bracket:

1. First, I put the front on axle stands and removed the belly cover (both covers under the engine and transmission) and wheels for space.
2. Removed the front snub mount metal bracket (13mm) from the engine to allow vertical movement when jacking up the engine. The rubber mount was in perfect condition so I didn't replace it, nor put the bumper in the service position.
3. And then unscrewed the top nut of each engine mount. N/S is easy, just move the coolant reservoir (remove the sensor at the bottom of the tank) out of the way and the nut easily comes off with 13mm socket with some extension for reach. O/S was difficult, but managed to access from under; I fed the ratchet with universal joint from the rear of subframe, just enough room to crack the nut with the ratchet and unscrew the rest by hand.
4. Unscrewed the bottom nuts of each engine mount. They easily come off.
5. I prepared the new parts close by for a quick swap and to minimise the time the engine was jacked up.
6. Luckily I had a block of wood that covered the whole of oil pan so I used that to jack up the engine form the pan. Very carefully, listening to any knocks / clicks / screech / noise which might indicate any component under stress when lifting. Luckily nothing was damaged (or at least haven't noticed so far)
7. I checked on O/S mount on every half a pump of jack to see how much more the engine needed to lift to clear the top studs form the metal bracket. Repeated few times until I managed to wiggle it out with as little lift as possible.
8. Quickly replaced the mount, carefully aligned the mount with the two rubber studs at the top and one notch at the bottom of the mount.
9. Lowered the engine enough to put the top and bottom nuts for couple of threads so the mount wouldn't fall off whilst repeating #6-8 on the N/S mount.
10. Did the same for N/S mount. Much easier this side.
11. Lowered the engine and fastened the mounts. I think they're only 25N/m so just snug tight.
12. Repositioned the front snub bracket and put the screws in place, not tightened yet.
13. Ran the engine for a min to make sure nothing disastrous happened. Then tightened the front snub mount.

The alignment wholes were perfect on N/S but about 1-2mm off at the mount bracket on O/S:



I don't have the special tool (VW #3393), but noticed that my 13mm socket fit with very little play (14mm didn't fit through). Unfortunately the socket wasn't long enough to meet the three wholes but a deep socket would have been perfect. I tried to remove the engine mount bracket but whilst I was unscrewing the bolts, the subframe kept on coming down with it so I decided not to mess with it. I think I can live with 1-2mm misalignment, which probably has been for very long time.

Overall, most probably a placebo, the engine rattle on ignition and switch off has reduced dramatically and the gear shift is much much better. It feels, again most probably a placebo effect, that the power is transmitted to the axle with very little torque waste. It's such a nice feeling.

But the original noise I've been complaining about is still there, as before, more prominent when the engine is warmed up...! It's very much likely to come from the lower control arms... I'm quite competent with the components now so I'll get on with it once I have enough money to buy the lower control arms!

For the first time, I had little help from fellow forum users and managed to get these jobs done, which is a huge achievement for me! I like to keep a note of what and how I've done it on this forum, and hopefully my notes will be some use to fellow drivers with B5 A4 or Passat!

Happy DIY and motoring!