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Discussion Starter · #1 ·
OK - first thing to note - the front diff fill plug. I was able to get to it using a wobble extension. I got it out without much issue, and thought the worst was behind me. The fluid in the front diff was dark and smelly( 35K miles). I installed a new drain plug, and filled it with new fluid. So far so good. But THEN - I tried to put the fill plug back in. I have never cursed so much in my whole life. I just could not get the threads started! I tried the wobble bar that I used to undo it, but I could not turn it smoothly enough to start the threads. I tried a universal joint - same thing. At this point I was getting nervous. Then I recalled someone mentioning a ball ended allen wrench. I tried that but mine is L shaped, and I could not turn it more than maybe 30 degrees before the shorter end whacked against something else. So what to do? I took a dremmel to my L shaped allen and cut the short side off, so it was perfectly straight, and about 4 " long. Within 5 seconds of doing that I had the fill plug in. Then I used the wobble extension again to tighten it. So, be sure you have a straight ball ended 5 mm allen!

Rear diff was easy - the fluid looked brand new.

Haldex was easy - but I think I underfilled it. It snowed the next day and I was not feeling the AWD kick in right away. So I put it back up after a long drive and found I was able to add another couple of oz, maybe 100 ml tops. I did not clean the screen - I'll do that next time.

All in all I am very glad I did it myself and did not have the dealer do it, or some other shop. now I know what I am doing for the next time.
 

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Thanks for sharing your experience. I'll be doing these maintenance items myself also in the future, probably aim for 25k or 30 k miles to do it the first time?

Do you have any pictures, or a link to a DIY or instruction?
 

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did you clean the pump filter of the haldex unit? if so you'll want to run the car for a but for the pump to prime and then refill before buttoning up, i was able to get 3-5 more pumps into the haldex unit after i ran the car for a couple minutes, which i'd guess is around the same amount you were able to add.

Another option is to do an output test of the haldex pump via VCDS.
 

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Discussion Starter · #4 ·
did you clean the pump filter of the haldex unit? if so you'll want to run the car for a but for the pump to prime and then refill before buttoning up, i was able to get 3-5 more pumps into the haldex unit after i ran the car for a couple minutes, which i'd guess is around the same amount you were able to add.

Another option is to do an output test of the haldex pump via VCDS.
I did not clean the filter this time - considering how clean the rear diff fluid was I don't think my haldex has kicked on very often. But I will do it next time. How does one do that VCDS pump check? I do have an OBDII.
 

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I did not clean the filter this time - considering how clean the rear diff fluid was I don't think my haldex has kicked on very often. But I will do it next time. How does one do that VCDS pump check? I do have an OBDII.
The filter is for the Haldex, not the rear diff. The final drive and Haldex have separate circuits. The Haldex is what gets gunked up. It makes sense that the rear diff was clean. If it's like the last 30 years of BMW rear diffs (where it takes all of the load) the original oil and rear diff will outlast the car. For your VW, the friction material in the Haldex unit is what plugs up the filter.
 

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I did use those lab wash bottles - I saw you recommend that in another thread and thought it was brilliant. They worked great - thank you.
We use them in racing because we are changing diff and trans oil at least once per event. With the fact that every manufacturer seems to put plugs in the hardest point to reach the work like a champ. Plus, if you poke a hole in the lid and stick on a tube, it's a great brake bleeder bottle. If you are really thrifty, some JB Weld and an old fridge magnet will allow it to stick to the rotor when bleeding brakes.
 

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I did not clean the filter this time - considering how clean the rear diff fluid was I don't think my haldex has kicked on very often. But I will do it next time. How does one do that VCDS pump check? I do have an OBDII.
Haldex pump is on all of the time just controlled via PWM to range from 10% to 100%, it just depends on how much slipping and ware on the clutch material.

For me, I noticed the clutch material settles out of the haldex fluid and cleaning the pump was well worth the extra 15 minutes, as some of that material clung to the pump housing that needed a wipe with a rag.
 

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I'm a bit confused by this post, when you say "front diff" are you referring to the transaxle? I went through the service booklet for my 2018 Alltrack and they make no mention of changing the transaxle gear oil. The only service they recommend for the front gear box is the fluid for the locking front diff on the GTI models so equipped. As far as I'm aware the 4Motion wagons DO NOT have the locking front diff, please correct me if I'm wrong. My assumption is the transaxle on the 4Motion car should be treated like any "normal" transaxle, the manufacturer says it's "lifetime" fluid, but a meticulous owner should change it around the 100,000KM mark.

On the rear VW does say to change the Haldex clutch oil, which I plan to do in the next year.
 

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Discussion Starter · #13 ·
I'm a bit confused by this post, when you say "front diff" are you referring to the transaxle? I went through the service booklet for my 2018 Alltrack and they make no mention of changing the transaxle gear oil. The only service they recommend for the front gear box is the fluid for the locking front diff on the GTI models so equipped. As far as I'm aware the 4Motion wagons DO NOT have the locking front diff, please correct me if I'm wrong. My assumption is the transaxle on the 4Motion car should be treated like any "normal" transaxle, the manufacturer says it's "lifetime" fluid, but a meticulous owner should change it around the 100,000KM mark.

On the rear VW does say to change the Haldex clutch oil, which I plan to do in the next year.
The front diff is what VW calls the front "bevel box" or "bevel gear". It is not the transaxle. It is a small gear box that is similar to a lot of other AWD vehicles. If you look at this post, it will be more clear to you:

https://forums.vwvortex.com/showthr...evel-box-haldex-and-rear-differential-housing


And yes, a think the phrase "lifetime fluid" is absurd. I change my fluids at normal intervals. By the look of the front diff fluid, it was ready to be changed.
 

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I did this complete fluid change (transmission, front bevel box, rear diff, rear Haldex, Haldex screen cleaning) at around 20K Km for both my 2016 Golf R and 2018 GSW 4Motion. All with OEM fluids. I think it's cheap peace of mind, as I always wondered if any of them were underfilled from factory etc. At least I got any break-in metal etc out, and from now on I'll stick to the regular service intervals.

The Haldex pump screens on both my cars had significant sludge on them, so I'm glad I didn't wait until the recommended service mileage.
 

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By the look of the front diff fluid, it was ready to be changed.
ahh yes the tried and true "it looked bad so it must have been time to change it". I've used the same method on changing my TDI oil, frigging thing only goes 200 miles before oil change now :mad: but it's cheap insurance and I sleep better.
 

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ahh yes the tried and true "it looked bad so it must have been time to change it". I've used the same method on changing my TDI oil, frigging thing only goes 200 miles before oil change now :mad: but it's cheap insurance and I sleep better.
it's a bit of an apples to oranges comparison...

yeah, color isn't much of an indicator on motor oil, since you have the darkening from combustion byproducts; that's not the case with gear oil, where a change in color is a pretty good indicator of oil degradation and/or contamination.

There's also no oil filter, so you have one way to remove contaminants: change the oil.
 

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But we can both agree sight and smell are a bit different than a UOA?

I understand that people are conservative with maintenance but with synth gear oil used today on a light duty application, i'm not going to be losing any sleep for quite some time.
 
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Just wanted to add my experience too.

Same experience as everyone.
Putting the fill plug back on the front bezel box was frustrating because of the clearance.

I ended up finding a regular sized flat head screw driver that could sit inside the fill plug and that was what worked for me.
 

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But we can both agree sight and smell are a bit different than a UOA?

I understand that people are conservative with maintenance but with synth gear oil used today on a light duty application, i'm not going to be losing any sleep for quite some time.
of course. That said, 1) I've seen a fair number of UOA's on factory fill gear oil, and they always show the same thing: there's a fair bit of contamination in the factory fill. 2) the cost of UOA is roughly the same as the cost of changing the fluid. So, while a UOA could provide some insight, I'm ok looking at the fluid and making a determination.

I've had 3 different Haldex-equipped vehicles (all different manufacturers), and in every case I've seen the exact same thing: the front bevel gear fluid looks black and has a fair bit of visible contamination in the drain pan after 30-40K miles, and the rear differential fluid looks brand new regardless of when you change it. Based on that, my plan is to do an initial change at 10K, then 30K on the bevel year and 100K on the rear differential.
 
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