Nicholbry

Hello guys. I am about to change my Differential Fluid (I'll be sure to remove the filler plug first) . I have a '90 S4 and I was wondering what the plug sizes were (filler&drain). I have found here on Rennlist that some say 17mm while someone else said 10mm. Are there different sizes for different year cars?

Thanks,

Scott M.

Early cars used the internal 17mm (sourced via Snap-On) and the later (borg warner trans IIRC, 85+) used the 10mm hex. At least the 86.5 I just did had 10mm.

PorKen

Starting with the 86.5, the plugs are bolt threaded, and use a sealing washer. Prior to this, the plugs are pipe (taper) threaded.

Also for '86.5, automatics have a drain plug on the bottom of the diff, because the right exhaust pipe is in the way. Manuals are shorter, and sit further forward, so they don't have this.

Rob Edwards

My 90 GT is 10 mm hex, as stated. (Of course, I bought a 17mm hex socket online soon after getting the car, before I actually got under it...... ) You'll want a 3-in extension, that should put the socket wrench aft of the exhaust and just in front of the battery box.

borland

Use the appropriate size wrench regardless of year model.

Mike Frye

Rob,

You could probably find someone on here who's looking for the 17. I had a bugger of a time finding one. I think John (Tomcat) was looking for one, but he may have found it.

tomcat

My '85 has a 17mm:

AST 6500-17
17mm Allen for Passats since 1998, Audi A6 1999-2004, 02-05A4: Front and rear axle bolt (AWD).

Straight from the label on the package.

FlyingDog

I bought mine at a NAPA store. I just told them I needed an Audi/VW tranny drain plug socket. They knew exactly what I needed. Tranny/diff drain/fill plugs that need 17mm sockets are becoming more common so the auto parts stores sell them in sets. The Mercedes NSG370 tranny in my Jeep has 17mm fill and 14mm drain. I've been told Autozone sells a 3 piece set of 17,14 and 10.

Scott M.

Just got back from Autozone and the three pc. set (17,14,10) is $9.99. What a bargin!

Nicholbry

After posting my question, I decided I just couldn't wait as my car's a$$ was jacked and ready to go. Looking at the hole size in the plugs I could not discern the size, so I got a 17mm as it seemed that most of my fellow Rennlisters have it. Of course, it turns out to be a 10mm; my luck these days.

Upon revisiting my post here I see that quite a few of you responded in an effort to help me out. You guys are the greatest and I can't imagine what 928 owners did prior to having this resource for help and everyone's collective experience.