How to change C4 transmission oil

[Homard]

Hi I'm new to owning a Porsche and new to fixing my own car.

I bought a 1991 Red Convertible C4 964 which I have enjoyed a lot

I watched a video on how to change the oil which I will try on my own soon. With 96000 miles on my odometer, I am willing to change my transmission oil as well as the front differential's oil. Can someone tell me how and what kind of oil I need for the transmission and the differential? It would be great if you could send me some pictures. My mechanic is supposed to be really good but he's never available.

Thanks for your help

[Augurean]

Actually just changed both last weekend myself...

Do you have your owner's manual with your car? In the back it lists all the different fluid capacities and types. Trans fluid is 75W90 (front and rear), the rear takes about 4.02 quarts and the front is just over one (1.27 I think, but can't recall that one exactly). You may want to measure how much comes out when you drain it, to make sure you haven't got a leak.

You'll have to lift the car up and take off the front and rear undertrays to get at the transmission and front diff. It'll require a large hex key and an extension to get enough torque on it to break the plugs loose. Make sure and do the top one first, as you don't want to pull the lower one and find out there's no way of getting the fill plug off.

Then get a hand pump ($12 at an auto shop), stick one tube in the fill hole, and start pumping. Probably a two-person job with one holding the tube in place and the other pumping.

Good luck, hope you're enjoying the new ride!

[Newsboy]

To make filling the rear diff. a little easier, I took a 1" diameter piece of clear plastic tubing. Placed one end in the diff. and a funnel on the other end. Raised it up above the rear wheel, and poured the oil in. The consensus seems to be either Swepco or Redline 75/90.

[Traveller]

Go to the Maintenance section in the following link and click on:

• Differential Oil Change
• Transmission Oil Change

Actually, both have a differential. The titles could have been better chosen.

P-Car Workshop - 964

[mattC2993]

Originally Posted by Newsboy

To make filling the rear diff. a little easier, I took a 1" diameter piece of clear plastic tubing. Placed one end in the diff. and a funnel on the other end. Raised it up above the rear wheel, and poured the oil in. The consensus seems to be either Swepco or Redline 75/90.

That is what I do on my '95 (at least until I invest in a pressure pot or pump). For the 993s at least, Mobil Delvac is popular. I believe it is the factory fill stuff.

[Augurean]

Originally Posted by Newsboy

The consensus seems to be either Swepco or Redline 75/90.

I used Redline 75/90, as I've heard good things about it. However I've also heard that going to a synthetic from a regular oil can cause leakage, but I'm not entirely sure on that one.

I've used a long tube and funnel before, but I found it a bit easier with a pump. It's not necessary, but worth a few bucks if you find a cheap one.