911 Turbo/ 930 gear oil recommendation

[CVJR]

Hi All, I'm a newbie 1987 911 Turbo (or is it a 930?) owner. 39,000 miles, current gear oil not known. Which transmission gear oil to use? Do all '87 Turbo's have LSD or do I need to check that to detirmine gear oil spec? I read a bunch of the 911/915 threads on gear oil (Kendall v. Swepco), but not sure if that relates to a 911 Turbo 4 speed. I bought Swepco 201 from our host but now having doubts if it's the correct gear oil.

Thanks for your reply.

[E-man930]

I filled mine up with Royal Purple 75W90 gear oil.

[CVJR]

Thanks E-man, best of luck getting your car back to running state.

[BMAN]

When I bought my 930 I used Swepco 201 and never had a problem. Great to see another nice Porsche in Maryland.

[lucittm]

There was some discussion about conventional oil for the very early transmissions due to the tighter tolerances used back then and now the synthetic oils are recommended for the more modern drive trains. Of course this could be entirely related to the fact that synthetic oil was not even a dream for most of us from 1950-1970. I think the synthetic oils offer better protection across the temperature spectrum and tend to not be as thick when cold. Cold gear oil puts a lot of strain on those rotating components.

I used Mobil Delvac 75W-90 gear oil because that is what was recommended by Porsche for my car. It is approved for LSD and if you are not sure if you have LSD, it is better to use an LSD lubricant than to not. I had a hard time finding this oil but the good people at Lufteknic had it for $55 a gallon. Maybe more expensive (delivered) but I sleep well at night.

Mark

[JFairman]

[QUOTE=CVJR;6112476]Hi All, I'm a newbie 1987 911 Turbo (or is it a 930?) owner. 39,000 miles, current gear oil not known. Which transmission gear oil to use? Do all '87 Turbo's have LSD or do I need to check that to detirmine gear oil spec? I read a bunch of the 911/915 threads on gear oil (Kendall v. Swepco), but not sure if that relates to a 911 Turbo 4 speed. I bought Swepco 201 from our host but now having doubts if it's the correct gear oil.

You have the Swepco 201 and it is a quality petroleum base GL5 oil that is the right stuff for the porsche steel synchros and 930 gearbox. 4 quarts of the Kendall sounds like a very good alternative that is almost half the price of a gallon of Swepco 201 here on pelican Pelican Parts - Product Information: KEN-LSD-7745.
I hope that price doesn't go up.

Not all 930 gearboxes have limited slip. There is a sticker under the hood and it will have the number 220 in the option list if the car came with LSD. If you rotate one rear wheel while the back of the car is lifted the other wheel will rotate in the same direction with LSD and the opposite direction without it.
You want 80w-90 GL5 gear oil with limited slip additive. Without the additive the LSD clutches will chatter when you turn and go around a slow corner like turning at an intersection or stop sign.
You can add 1 or 2 bottles of limited slip additive to the gallon of oil in it already if it doesn't have the additive and chatters. Drain out some of the oil first so it isn't overfilled if doing that.
Swepco 201 has the LSD additive in it.

You got advice from someone using Mobil Delvac synthetic gear oil in a 1991 964 turbo. A 964 turbo has a G50 5 speed transaxle made by Getrag and it has Borg Warner synchros that work fine with synthetic gear oil.

Your '87 930 has a Porsche made 930 4 speed transaxle that's very similar to the 915 transaxle and both have Porsche steel synchros that grip and work better in petroleum base gear oil.
Synthetic gear oil is great for the gearsets and bearings but a little too slippery for porsche steel synchros to do their job as well and the increased synchro ring slippage in synthetic oil may wear out the porsche synchros faster than dino petroleum base gear oil.

[E-man930]

Too slippery? What? Dude, more slippery = better in a gearbox. Less friction = less heat & less wear. If you have LSD add some Posi-Trax additive and call it good. I have been using Royal Purple synthetic gear oil in every fun car I have owned with nothing but better results than dino trans oil, including the 930.

[Roby466]

I was just looking at the same issues lately. I contacted the SWEPCO rep and he recommended the 210 or 201. Both the 201 and 210 already have the LSD additive in them and he said that the 210 was a bit better in high torque applications and high heat (racing). The 201 will be better if your synchros are already worn out a bit. I filled my 930 with the 210 and my friend's 77 911 with the 201, both feel better than before. The 930 and 915 transmissions do like a bit less slippery oil because of the bulk gear synchros, unlike the G50 which has Borg Warner synchros like all modern cars. You have the good stuff with the SWEPCO 201.
Nice car by the way!

[Tilikum Turbo]

SWEPCO ain't cheap, but then neither is a rebuilt Porsche tranny.

[mark houghton]

Swepco 201 in mine. I replaced whatever was in there when I first bought the car, the gears still go round and round, the tranny shifts, the LSD doesn't growl, and the car goes down the road. What else could anyone want?

[SEE YA]

Anyone got any tips on changing the geabox oil on a 930. Things that make the job easy. I am going to try Swepco gearbox oil.

[Dave 86 930 Fl]

Recommended by the 901 Shop for my track 930.

MonolecŪ Gear Lubricant 703 - 704 on Lubrication Engineers, Inc.

I change the oil every 20 hours and so far so good. The trans shifts a little hard when cold, but works great once the temps go up.

[CaptainCalf]

Originally Posted by CVJR

Hi All, I'm a newbie 1987 911 Turbo (or is it a 930?) owner. 39,000 miles, current gear oil not known. Which transmission gear oil to use? Do all '87 Turbo's have LSD or do I need to check that to detirmine gear oil spec? I read a bunch of the 911/915 threads on gear oil (Kendall v. Swepco), but not sure if that relates to a 911 Turbo 4 speed. I bought Swepco 201 from our host but now having doubts if it's the correct gear oil.

Thanks for your reply.

Very nice 930! Big Mike over at JB Racing builds 4speed LSD gearboxes with his eyes closed and both arms tied behind his back and he recommends Swepco because it's less slippery, so that's what I use...

[David]

I've been happy with Swepco but a very experienced racing buddy was praising Royal Purple as I watched him pull the gears out of his Star Mazda formula car for inspection the other day. He said it's night and day better than Mobil 1 but that may not be saying much.

[jwasbury]

I just loaded my gearbox with Motul Gear 300LS. I'm not sure what was in there before (put in by wrench that rebuilt the trans), but it was red in color. So far, so good. I did a track day on May 4 and maybe it was placebo effect, but my gearbox felt better than ever.

[Geary]

"Better feeling" oils aren't necessarily protecting parts better, they're merely allowing smoother shifts. Long term EP (extreme pressure) protection is far more important if doing any track/street racing. The two factors (EP protection / smooth shifting) are not related, so a particular oil may provide silky smooth shifting while providing piss poor EP protection. I could name oils that fit in this category.

Swepco provides excellent EP protection, whether installed in the 930 4-speed or G50/50 & G50/52 5-speeds. Swepco also provides good shifting in the 4-speed, and decent shifting in the 5-speed. The synthetics mentioned in this thread may provide slightly smoother shifting, but they probably won't provide the same level of long term EP protection.

A number of companies making synthetic gear lube have changed their formulation over the past few years , and the end customer has been paying dearly for these changes (which never seem to be for the better). I see the 901 Shop mentioned .. they are just one facility that has learned the hard way in their own race car, when using one of the "evolving" synthetic oil mentioned in this thread. So, they tracked down a better solution, settling on a very high quality non-synthetic .. similar to Swepco or Kendall in terms of long term EP protection.

In fact, there are a fair number of well-known shops who have gone back to "known quality" non-synthetics for their customers late model Porsche race cars .. something to think about at the next oil change.

[pdqcarrera]

+1 for Swepco. Been running it longer than I can remember or would rather even want to admit. In both a 915 race car and 930 4spd street car it's proven to be the best. The 2 times I've tried another (recommendations by others) I noticed a detrimental difference in cold and/or hot shifting.

[Les Paul]

4 or 5 years ago my 76 was getting harder and harder going from 3rd to 2nd. So I went from the factory short shift kit to a wevo with the ujoint too and swepco 201. Shifts way better and easily goes into 2nd. Not sure what made the difference but it truly did improve what I thought was a gearbox that might need major service. Good looking car.