Gear oil change in a 964 - questions

My 964 has 50,000 miles on it. At the 45K service my wrench did not change the gear oil claiming it wasn't necessary until 60K. I'm not comfortable with that and would like to switch to Swepco anyway. OK, here are the questions:

1. Which Swepco? Manual says 75W90.

2. Looks like the drain plug is a round plug with a 10mm allen head (located just in front of the engine / transaxle, with engine pan removed only). Is this right?

3. Safe to assume that the fill plug is nearby also? Will I need to remove the center pan?

4. Is there a washer (gasket) under the drain plug/fill plug that should be replaced?

5. Considering my mileage, is it necessary to run clean dino for a while before going to swepco?

As always, I am indebted for your assistance.

Mike

Mike,

I changed to Swepco a few thousand miles ago and do NOT like it at all. The shifts are very balky until the car is warmed up (especially on cold days), and even then it's not as smooth as it used to be. I plan on switching to Mobil 1 pretty soon. Perhaps you'll have better luck with Swepco, but just wanted to pass that along.

Drew
92 C2

Drew,

Have been doing a bit of research and it appears that Swepco may not work as well in our G50's as it does in the 915. Sounds like you've confirmed this. Have you heard that Mobil 1 is the better choice?

Also, where and what size are the drain/fill plugs (or will it just be obvious once I get under there?).

Thanks,
Mike

It pays to do your homework before you do the job! G-50's tend to favor synthetics,915's have to have Swepco.Redline makes a really good synthetic for your G-50,and,of course,
the Mobil 1 is a good choice.

Hi Mike,

I've no idea what gearbox oil was in my 85 Carrera when I bought it but I switched to Mobil 1 about a year ago and although it's a 915 box it's exceptionally smooth and I can't say it needs to be warmed up at all. Mind you I'm in South Africa so it's not like we experience any seriously cold weather.

Cheers
Ralph

The G50 will be happier with Mobil 1, Swepco is better in the 915's because of the friction required by the syncronizer design.

Mike,

I also have heard the G50's benefit more from synthetics (Mobil 1 or Redline). I had Swepco in mine last season and can't say it was bad. Shifted just fine. I plan to use synthetic this season to see the results.

FYI, if you happen to go the Redline route. I spoke with a fella named Dave Granquist at Redline and he recommends a mixture of 1 quart Redline Lightweight Gear Oil and the remainder Redline 75W90NS gear oil. Dave has a 993 I believe.

I believe the G50's are somewhat the same throughout the years. My 87 has a 10mm inhex plug for the drain and fill and uses aluminum seal washers. The fill should be on the driver's side (LHD) and near the throttle linkage bell crank. At least that's where it is on the 87 trans. Really shouldn't be hard to miss since they are the only inhex plugs on the trans.


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Kevin
87 Carrera

[This message has been edited by KTL (edited 03-25-2001).]

Thanks to everyone! The trans is draining as I write this. Probably the most valuable advice was to loosen the fill plug before starting. . . it was a mutha! I'm sure it's the first time it's ever been removed. The old juice looks suprizingly clean with only a small cluster of grey mush adhereing to the magnet. . .nothing solid what-so-ever (squished it around in my fingers to be sure . . .kind of fun in a sick sort of way).

Anyway, I'm heading out now to fill it with Mobil 1 75W90. BTW, the sealing washers are the exact same ones needed for the oil drain plugs. . .just happen to have some on hand waiting for the next oil change. Used a small amount of t-tape (as recommended) on the bolts so that they seal well and come off easier next time.

So far, going veeerrrrryyyy smooth.

With sincere appreciation,
Mike 94 C2 cab

Had the same problem when opening my drain plug. There was no way in creation I was getting that plug off without either serious help (not available), an impact gun (not available), or a creative plan. (Had that!!!)

I ended up jacking the car up another half an inch or so off the jack stands, securely placing the socket into the plug, attaching an old breaker bar, and placing another jack stand under the handle of the breaker bar. As I slowly lowered the weight of the car onto the breaker bar, it finally came free. I only wish I was able to measure the actual torque that was required to break that thing in the end.

Interesting about the Swepco though. I too have the warm up issues. Never heard of that before - and now can't wait to try some Mobil 1.

Brian
'91 C2

Ha! Great idea to open the filler plug...I wasn't so creative. I laid lengthwise under the car (I know. . .not very smart) and planted my 11D squarely on the handle of the wrench while bracing my hands against the front wheel. . .and just pushed as hard as I could. . .just when I thought it would never work. . .BAM. . .it came loose. I love that feeling. Fortunately, the drain plug was more forgiving.

Anyway, I used one of those metal "syringe" type things to transfer fluid from the bottles to the gear-box. It worked, but it was messy. . .thank goodness for kitty litter. I got things all buttoned up and took her for a spin. Man, I love that car! The shifts were fine before, a nice crisp click into each gear. Now, the shift is smoother and still crisp but without any metallic sound or feel. . .almost as if the grears have a fine layer of teflon over them. The shifter just slides/snaps cleanly into and out of gears with a wonderful feel. So far, I'm sold on Mobil 1 for my G50 (and for my oil tank).

Thanks again for all the advice. . .another good one was to do this project in the driveway, rather than the garage!

Best,
Mike 94 C2 cab