rnln

due to the "enhance leak" of synthetic on old car, I decided to go with 20/50 on my 64k miles 1988 engine. On the tranny, I also affraid of this reason and thinking of non-synthetis fluid. But I have read so many people still use synthetic on the tranny. Why? Don't yuo affraid of the "enhance leak" just as your engine? Or the tranny won't get leaked?
Thanks.

pjc

Many less options for oil leaks on the transmission - I personally go with standard gear oil anyway.

PJC

BER

Your 1988 911 has the G50 transmission and should use synthetic gear oil.

Dino gear oil is used in the 901/915 gearboxes.

rnln

BER,
If I go for non-synthetic now, will it hurt anything? Or just the performance? And I can always switch to synthetic right?

.... One last question before I do it tomorrow and 2 oposite response again. arggggggggg
I don't mind spend some more money on synthetic for the good of it but I affraid the synthetic will "enhance leak" my tranny. And I know how expensive rebuilding tranny can be, experience already. Therefore, I don't want the non-synthetic hurt my tranny neither

If I try synthetic now, and go back to the non-synthetic = people said "YOU CAN'T".

Give me your opinion guys.

ked

rnln, your car's G50 came w/ "dino" transaxle oil from the factory. now, you can put in either;
a) dino oil that meets or exceeds the factory spec (GL-5 / SAE 90), or
b) synth oil that meets or exceeds the factory spec.
you can switch back & forth if you want to. prevailing wisdom is that the trannys aren't as liable to leaks when switching to synth as engines are.

I switched from dino to Mobil1 in the engine when I got my '87 @ 76K mi. no change in leaks (an occasional drip, looks like I'll be replacing oil return tubes in a year or two).
I also changed the tranny from (what smelled like...) dino to Mobil1 synth. Felt a little smoother. No leaks before or after. 109K mi at the present.

BER

Do a "Search" on gear oils. Most experts recommend synthetic oil in the G50's.

You should ask what oil to put in your engine if you want many different answers!

rnln

ked,

very detail, straight to the point response. Great appreciate. But I have never heard of "dino" before. Maybe another trip to an autopart store. But another thought.. manual said 75-90, store has 85-140 and synthetic, most people here said SAE 90 is fine => to me it seem like 85-140 is definitely good for it since it's has 90.

BER,
remember years ago I always used Penzoil and only know Penzoil 10-40. When I had my previous BMW and MB, I used 20-50. After I bought this old 911, I heard so much of "you MUST use synthetic" but after I ask this question here, it seem like it is not a "must" but rather be a "better". To me I think it definitely better to use synthetic if the car is new, or at least a newly rebuilt engine. Since my car is unknown of everything, I think I am going to go with the mineral 20/50.

Thanks much guys.