How To: Reduction Gear Oil Change

[powersurge]

If is very easy to get the right tranny fluid...

Get a gallon of Valvoline MAXLIFE (RED JUG) mercon dextron AT fluid. It will work on any car any model..

I get it at Walmart,. I use is on all of my 5 cars...

[goldbrick]

This isn't new tech, it's what almost every FWD transverse-mounted (which is almost all of them) drivetrain has with an automatic. The B5 Passat is a bit different that most FWD cards in having a longitudinal drivetrain, presumably so that AWD could be offered.

When I was reading up on this I did notice that lots of older cars used AT fluid in the diff. Most of those articles also mentioned that the fluid should be changed every 30k-60k miles. VW claims their transmission fluid is 'lifetime' and never needs to be changed. A company called ZF actually makes the transmissions, though, and I believe they recommend changing the fluid occasionally although that's a bit nebulous since they don't have much official information out there. Since it's a separate hole to change the diff fluid on the VW I just use gear oil for it since that is what is specified by both VW and ZF. Anyway, I sure learned something from this thread.

[LeftieBiker]

VW claims there transmission fluid is 'lifetime' and never needs to be changed.

Volvo made that claim when the 850 came out, and even omitted the usual drain and fill ports, IIRC. Naturally, a lot of early 850 transmissions have been replaced, and they later came with the usual ports, drains, and service recommendations.

[goldbrick]

There's no fill port on the ZF transmissions either. You have to pump the fluid into the transmission from below. And of course, since it's an AT this has to be done while the pump (ie the engine) is running. The car has to be level, with the transmission at the correct temperature, etc. It's a major PITA. At least for the diff you just open the plug and fill it until it drains out. Same as most cars I assume.

[LeftieBiker]

The workaround for the 850 was to do a fluid exchange via the lines to the cooler.

[Nubo]

VW claims there transmission fluid is 'lifetime' and never needs to be changed.

Volvo made that claim when the 850 came out, and even omitted the usual drain and fill ports, IIRC. Naturally, a lot of early 850 transmissions have been replaced, and they later came with the usual ports, drains, and service recommendations.

"God help us; we're in the hands of engineers"

[Valdemar]

I'm at 156k miles and there's now noise seemingly coming from the gear. It started as a faint gear like clatter at low speeds a while back, but now I can hear it on the freeway when the motor sends torque to the wheels, its kind of an odd noise like a quiet ICE engine running. Gear oil never changed. I'm guessing too late now, huh? Dealer once confirmed the noise was coming from the motor/gear area.

[LeftieBiker]

I'm at 156k miles and there's now noise seemingly coming from the gear. It started as a faint gear like clatter at low speeds a while back, but now I can hear it on the freeway when the motor sends torque to the wheels, its kind of an odd noise like a quiet ICE engine running. Gear oil never changed. I'm guessing too late now, huh? Dealer once confirmed the noise was coming from the motor/gear area.

Once you are sure it's the reduction gears, you could try an additive with extra moly, or whatever they use these days to cushion mating gear surfaces - if you can find one compatible with the recommended (fresh!) oil. The good news is you can likely find a used assembly in good shape. I don't know what the Leaf reduction/differential setup looks like: is the motor mated right to it...?

[Valdemar]

I'm at 156k miles and there's now noise seemingly coming from the gear. It started as a faint gear like clatter at low speeds a while back, but now I can hear it on the freeway when the motor sends torque to the wheels, its kind of an odd noise like a quiet ICE engine running. Gear oil never changed. I'm guessing too late now, huh? Dealer once confirmed the noise was coming from the motor/gear area.

Once you are sure it's the reduction gears, you could try an additive with extra moly, or whatever they use these days to cushion mating gear surfaces - if you can find one compatible with the recommended (fresh!) oil. The good news is you can likely find a used assembly in good shape. I don't know what the Leaf reduction/differential setup looks like: is the motor mated right to it...?

I guess it won't hurt to change it, sounds like an easy enough job. I'm at a point where a need to spend $500 on the car will be enough of a reason to send it to junkers. The dealer couldn't pinpoint the exact location of the noise, but given the nature of it I'd be very surprised if it is not the gear. I have heard noisy diffs, it is similar.

[Dala]

Did a replacement in my 2015


I went with the Redline D6, 2 Quarts needed (2x946ml)


After removing the skidplate, the reduction gear case is exposed. The plugs for fill and drain are 10mm insex. Start by checking that the fill plug can be removed! It is in the top right in this picture.


When they designed this, they made an economical decision to use aluminium crush washers. These are absolutely not reusable and I instead refitted the plugs with copper ones. I guess if you make tons of cars, saving 0.01€ on a plug gets worth it pretty fast!


My average trip meter consumption is now sitting pretty at 7.6km/kWh, let's see if I can get it to 7.7 before summer is over This modification will probably help most in freezing conditions though.