G 50 trans fluid

[cmcfaul]

Want to change the trans fluid in my 89 G50 Carrera as I have no idea if its ever been done before. What's the best fluid to use and how may qts?

Thanks,

Chris

89 G50 Carrera
73 911E

[DWeg1998]

LSD or no?

I’ve tried Royal Purple, Mobil Delvac and Redline and I’ve had the best experience with Royal Purple. Easy to find too at your FLAPS

You fill it until it overflows. Around 3 bottles if I recall

[cmcfaul]

Has LSD

What viscosity? Syn or other.

I did it on my 73 E with the 915. G50 is different.

Thanks,

Chris

[Matt Monson]

Use the factory fill Mobilube PTX.

[DWeg1998]

75w-90 Synthetic is preferred by the consensus for G50

[Jesse16]

I think its 3 or so quarts, any GL-5. I have used non-synth (likely what the factory used) Kendall that our host sells and synth from Brad Penn in the 75-90 weight. Only minor thing I noticed was the non-synth. was slightly slower feel when shifting from cold. I think you could use any Castrol, Valvo, Mobil product from your flaps and be fine. This is old school stuff. It is fine if you use LSD rated oil if you see it on the label. If your tranny has LSD, you need that rating.

[Bill Verburg]

Originally Posted by Matt Monson

Use the factory fill Mobilube PTX.

+1

unless you are tracking the car, then use Delvac

[Nader]

Huh, did Swepco fall out of favor?

[Bill Verburg]

Originally Posted by Nader

Huh, did Swepco fall out of favor?

Swepco is great for 915s still good but not as good for g50

[Jesse16]

Maybe Swepco makes a GL-5 rated product. The 915 gearbox and G-50 are different. Hypoid gears maybe ??

[hcoles]

After reading posts around here I recently switched to this - Kendall Super Three Star 75W-90

[chuckr]

I have had just about everything in my G-50, even Swepco. I’m with Matt and Bill, go with what the factory and Porsche Motorsports use. Mobile
New shifter bushings also make a huge difference!

[jlex]

Originally Posted by Matt Monson

Use the factory fill Mobilube PTX.

Apparently no longer available.

Wasn't original non synthetic? Should be go to a synthetic ?

[Nader]

I have an Alfa and Ferrari. People swear by Redline 75/90 NS for both. It's GL-5 as well.
For both transmission and diff in the Alfa, and transaxle in the Ferrari. They both have notoriously difficult 2nd gear shifting issues. How 'bout Porsche, any good there? I'd like to consolidate my fluids/lubricants collection (until I retrofit everything to electric drivetrains).

[Sabai]

I use motul 300 in my G50 and it is EXCELLENT. I believe you need the one with the LS additive(s).

https://www.motul.com/us/en-US/products/gear-300-ls-75w90

[Matt Monson]

Originally Posted by jlex

Apparently no longer available.

Wasn't original non synthetic? Should be go to a synthetic ?

https://www.*************.com/product/00004320420L.html

[wildcat077]

I use Mobil Delvac synthetic in both my G50 911 and my 944 race car with LSD ... been doing it for the last 7-8 years with good results !

[Bill Verburg]

Here's some usefl data

[aread]

75W-90 Delvac +1

[Techno Duck]

Redline 75w90 NS. If you have limited slip, add a little friction modifier.