Suction noise after transmission fluid/filter service

[JamesLawrance]

There's quite a few different size filters for the 5HP24A; 22mm, 26mm and 32mm. Make sure you get the correct one! The genuine Audi/ZF filter for the RS6 is 22mm and the part number is 01L 325 429 B (Audi) or 1058.298.049 (ZF).

Automatic Choice in Bristol is the best supplier for these. Their part number is 5HP24A.FIL02 (After-market) or 5HP24A.FIL12 (Genuine ZF)

[bilko1]

No problem Matt

[allroadadi]

Update: I CANNOT find any of those kits here in US. Not only that , no audi dealer here sells them either which is ridiculous. All the Uk stores will not ship to US, eBay wants $70 for shipping…and am not sure it’s even more with Trumps new tariffs.

But, looking at the Vaico filter, the pick up tube is 19.5mm (so it’s not too long), but the O ring is tiny. Someone mentioned that the wrong skinny o ring was used by a Shop and caused the suction noise. I do have beefier o rings, and I almost want to try re-fitting a new Vaico filter (which I have, since I bought 2 because the 1st one came with the transmission gasket broken) with a bigger o ring and that might solve the problem. I am doing all the work on the car. No Shop involved but am using the online service manual and VCDS to fill properly (temperature and all that). It’s not my first audi transmission job, but only worked on 2.8 L A6 (still have the car and no problems, no suction noises, but those cars have more vendors selling kits, where as the rs6 seems obsolete here). It’s a pain to find any parts for the rs6. I wound up buying a spare engine just so I can get parts I need

[srichards]

Does Rock Auto not list them? Normally they have absolutely everything.

https://www.rockauto.com/en/catalog/aud ... seals,8524

[allroadadi]

After taking some of my own measurements, I came to the conclusion that the noise is due to the fact that the suction pick up tube (which is the bottom of the filter that is measured in the pictures : 20mm or 22mm depending were it’s measured from) touches the bottom of the transmission pan on one side and on the other side has 2mm clearance. Basically it’s angled , maybe on purpose, but also is making me think that it would make the pump work harder to get oil due to very low clearance hence the noise.

When you use a vacuum cleaner and bottom out the end of the hose on a flat surface it stops sucking, if you lift one side it struggles a bit but has the most suction due to some clearance, but the most efficient way would be to hold it 2-3 mm from the flat surface…

[steve2003rs6]

Check the o ring is an interference fit.
In my case the garage fitted the wrong o ring.

Make sure there are no cracks in the filter. They are fragile.

If the filter neck is 20 mm (22mm inc recess) then you should be good to go. Presuming you have an original sump pan fitted.

Ps no idea why your pickup tube is angled when it’s installed. Further investigation on this needed ?

[allroadadi]

Yes, the filter neck is 20mm (or 22mm measured from that little gap). But it’s a Vaico filter.
Looking at the filter, it looks perfectly straight. But when I measured on the left side there was no clearance and on the right side there is maybe 2mm .
There are 70mm from the edge of the sum to the deepest point. The filter pick up tube sits at 68mm on the right as you look up, and 70mm on the left. It’s strange, I was surprised as well, but am also thinking that ZF designed it this way just in case it’s low on fluid and it will pick up some oil from the bottom of the sum or on heavy inclines?
I was tempted to cut the neck, but I’ll just try to buy the ZF filter. I was able to find just the filter. No kits.
It will take more than a week in shipping, so I’ll report the differences. I am also thinking the the thickness of the filter/plastic casing might be a bit different since the pick up tube is the right measurement. But Vaico should have taken those measurements. Maybe clarification on these differences might help someone that has a hard time finding ZF kits…

The O-ring is right. I tried the next thickness available and it will not go in. I was hoping it was the o ring, but to my disappointment it seems to be the total thickness of the filter. It’s my only guess left at this point.

[Shoppinit]

Could the sump be deformed?

[JamesLawrance]

Could the sump be deformed?

Sumps are quite thin on these so could be possible! When you remove the gearbox/engine, ZF recommend you don't rest the gearbox on its sump due to filters being cracked from the weight

[steve2003rs6]

If you are going to replace the filter anyway.
Why not trim the filter neck so you have 2mm clearance all around.
If it was mine I would give it a go.

Ps good point Shop and James. Damaged sump could be an option.
How did the car perform before you changed the filter ?

[allroadadi]

It did cross my mind to cut 2mm off the neck, but since it’s my second time doing the same service I decided to buy the ZF filter and compare them. If they are exactly the same after measuring again I will trim the ZF filter. It’s getting here next week.
My mistake was to throw out the old filter. I cleaned up after changing the oil and filter and tossed the old one in the garbage along with the empty bottles of transmission fluid.
The transmission ran fine before the fluid/filter change, but the car has been neglected so I figured just do it as precaution. The fluid was dirty, but no metal shavings. The sump pan had gasket maker on which made me think it’s never been serviced (but am not sure), as opposite to the paper gaskets that come in the service kits.

[allroadadi]

The sump pan is not damaged, the measurements are done on the transmission itself. The pan measures 70mm at its deepest point on both sides. The 68mm and 70mm measurements I talked about are from the upper edges of the transmission to the tip of the pick up tube on the filter. Basically the filter itself sits not plumb. Not visible at all, just by measurements. And it’s in all the way, torqued to spec. But my thinking is that maybe Vaico screwed up ?

[allroadadi]

Update: Well, this is going to sound pretty dumb, but the suction noise I was hearing was the front hubs spinning. Since I had the front end off for the timing belt/ chains and tensioner pads job, I never put the front wheels (or bolts back on). Even though I had my foot on the brake pedal, it wasn’t doing anything since the disc was not connected to the hub. Duh! I only was able to figure out once I saw that the speedometer was reading 20MPH with my foot hard on the brake pedal… I immediately went WTF is going on? My brakes are fucked?
Anyway, the ZF filter came and I used it anyway. The only difference between the Vaico filter and the ZF filter was the neck: ZF is tapered and Vaico is flared (which almost seems like a better idea since the o ring is trapped in there by the flare) . And after all that trouble I still can’t confirm that Vaico might not be good (maybe it is). I measured both on all sides: same.

[steve2003rs6]

Pleased you got it sorted. I think we have all had that
“ Oh No “ moment now and again.

[Shoppinit]

Haha. That's pretty funny.