Wrong Fluid in VW Autobox?

[SimonR]

While at the MG saloon day this afternoon, I was discussing my car's general lack of power and high fuel consumption with a few people and Dan (E_T_V) suggested checking the fluid level in the auto box.

He and I were surprised that the fluid wasn't red ATF, but instead looked and smelt like black-coloured manual gearbox oil.

Is this normal??!

Would this explain the problems I've been having with the car?

The transmission seems to work fairly well - it does eventually accellerate away from a standstill, picks up speed fairly well and also kicks down, but I'm concerned about the lack responsiveness and large fuel comsumption. Sometimes I get no more than about 250 miles from a tankful.

Cheers!

[G Force]

The oil in the auto transmission should be ATF. ATF takes on a black and burned smell when it has been overheated and/or the brake bands have been slipping.

I have never taken a VW box apart so my experience with that particular box is limited, but I think the final drive part of the box should contain gear oil and is seperate to the auto transmission fluid, perhaps someone with a handbook could confirm or disconfirm this. If it does then it is possible that a seal inside the box has gone allowing the ATF to be contaminated.

Whatever happens the first action I would do is drain and change the ATF fluid, then add some ATF conditioner additive such as Forte.

Gary:)

[BikerGran]

According to Mr Haynes,
the Automatic Transmission should containDexron II D type ATF or Duckhams Uni-matic
and the Final Drive (automatic transmission) takes Hypoid gear oil SAE 90EP or Duckhams 80W/90S

[G Force]

According to Mr Haynes,
the Automatic Transmission should containDexron II D type ATF or Duckhams Uni-matic
and the Final Drive (automatic transmission) takes Hypoid gear oil SAE 90EP or Duckhams 80W/90S


Thanks very much biker gran for confirming that, you're a star ;)

[BikerGran]

Speaking of which, do Duckhams still exist? Haven't seen any for years!

[Simon]

Well you know what I'd do...

[E_T_V]

I wouldn't say it was black, and it didn't smell burnt at all, (although I did get a few funny looks sniffing his dipstick ;)) Infact it looked nice and clean and still a gold-like colour. Certainly not red as it should have been.
It did smell of hypoid though and seemed a bit thick to me when rubbed between the fingers so I'm guessing someone filled the box with EP90 instead of ATF. I'd empty it all out and do the final drive at the same time and fill with the correct fluids.

Having oil that is too thick in the gearbox will kill the power and the economy as lots of energy is needed to pump the thick oil around. ATF is something like SAE30 or thinner!

[G Force]

Hi Simon if all the evidence points to the automatic transmission being filled with gearbox oil by mistake, draining and refilling the gearbox with the correct fluid will make a significant improvement to both performance and economy. Gearbox oil is not only thicker but it also froths and aerates, this will seriously affect the torque converter operation and the transmission itself.

Don’t forget to check my two favourite causes;) of poor performance and poor fuel economy the vacuum switch and the ORFCO valve are both OK as well once you have sorted the gearbox oil issue.

[SimonR]

Thanks to all for the insights.

I'm going to change the oils and see what that achieves.

I've just worked out that my Maestro is consuming as much fuel as my 3.6 Jag! This is not a desirable state of affairs...

I'll let you know how I get on. Then when I've failed I'll convert to manual and throw the autobox away!!

Mind you, I have found a reason to keep it - yesterday I had to eat a Chinese takeaway in my car and found the flat part of the centre console that you don't get with a manual box was very useful for keeping my spicy noodles on...!

[SimonR]

I bought the fluids this evening but didn't change them because I don't currently have any axle stands. Instead I removed the carb, dismantled it, and gave it a thorough service. Just as well really because parts of it were black inside and it was generally rather filthy.

I checked the ORFCO valve, the vacuum switch, replaced the O-Rings on the stepper motor and then once it was back together set the idle and mixture as per the technical manual.

It's surprisingly easy to do and has resulted in a MUCH more responsive car.

I'm off tomorrow to get a blow in the exhaust sorted (another part donated by my donor car!) then it's a case of replacing the gearbox oil next week.

It's already a *lot* better though so I'm hopeful that I can make the autobox work, at least for a while...

[E_T_V]

I've got an auto downpipe and tailpipe piece in almost new condition that are free to a good home. If I'd known I'd have bought them to MGSD for you.

[SimonR]

I've got an auto downpipe and tailpipe piece in almost new condition that are free to a good home. If I'd known I'd have bought them to MGSD for you.

Gah!! Well hold on to 'em if you don't mind Dan!!

My front pipe (sorry - my CAR's front pipe) is looking distinctly marginal.....

Cheers old chap.

[SimonR]

Just a quick update:

My father and I replaced the gearbox oil and topped up the final drive this weekend.

The oil that came out of the gearbox was fairly thick and brown in colour so I guess it really was the wrong stuff. Interestingly I managed to get almost a litre of oil in the final drive, before it began to run out again. Wonder how it got so low. I did check to make sure that there was no way that the two different types of oil were mixing, by leaving the drain plug out of the final drive while filling the main gearbox with ATF, and all seemed fine.

The car is accelerating a lot better now and the kick-down seems to feel different. Before the change there was quite a lot of pedal travel on kick-down, and it was quite an effort, whereas now it's right at the end of the travel and is a lot easier. Work that one out...!