Gonna clean up my tranny today and change the fluid, are new synthetic products worth changing over to or is good old 90 weight still the way to go?

Ian Stott
Moncton
Canada

SWEPCO likes 901 trannies....

this question was asked of dr evil at one of the trans sessions he has given and his reply was to run whatever is at FLAPS that is the right weight and forget about it. do changes and you will be fine, and have more $ in your pocket.

i for one am running FLAPS oil in my new evil trany and it shifts great.

cheers,

scott

word... the 10 bucks/gallon of 90w sludge works for me...

In old boxs like ours the lube should be changed often. So why throw good money away, you'll need it for other parts, 90W.

If you are allergic to gimmicks, use regular gear oil like Dr Evil recommends.. I use 85W-90 Valvoline, it stinks and you will sure notice if you have a leak.

In my 930 tans I used SWEPCO and didn't like the way it acted. I put some Valvoline in and it works much better. I think the swepco was a bit too slick.

that box has a diff style of synchro's IIRC (borg warner style right?)

and IIRC, there are a few types of swepco no?

i have heard that it was too slippery for the OLD style synchro's and that they were designed around the dino poo oil....

I've had Mobil1 and Sweepco in 901s. Frankly I can't tell any difference. I've got Motul with about a pint of GM friction modifier in the other p-car that has a ZF type LSD. I can tell a huge difference between the Motul and whatever was in there before...I don't know how old the other fluid was though. On the old fluid the tranny was notchy as all getout cold (50F in SoCal) and required double clutching to shift from 1 to 2 smoothly. All that's gone with the Motul. Am I fan of Motul? Getting there...

Later,
Kevin

Hey all, I am a bit biased, but not without some consideration of what I have seen. As many of you know my friend and mentor Red-beard (James) taught me EVERYTHING that I know about working on the 901 transmission. He looked into the whole Swepco thing and found it not to be 100% synthetic....as a matter of fact it is regular dino oil that has some stuff added in. He doesn't care for it and I was do not either. I have not felt a difference in cars with it.

My other reasons: I have worked on a lot of 901 boxes. The newest one is 30 years old and many have never been opend up. Most I have worked on are just getting tired....and were running regular 90w. I figure if regular 90w and probable neglect can get these boxes to 30years, then regular 90w and proper scheduled changes should take them far beyond that for less $$$.

But, if someone decides to go with expensive synthetic I would not think them a fool as mechanical work is as much psychological as physical. If it makes you FEEL better, proceed

"Often"? Why? Put in ONLY GL5, and forget about it. There is simply NO reason to be changing gear oil "often". None. I use 90-140, but straight 90 should be fine. You might wanna drop a little to grab a quick look at the drain plug if the tranny's getting noisy, but otherwise leave it alone.

The Cap'n

Here is an area where IMHO you are mistaken Cap'n.

There is a vent hole in the top of the tranny, correct? If it vents, it lets air in too, potentially letting in a bit of water too, even a little is bad. I realize it says top it up as needed, but if it "never needed to be drained", it would not have a drain plug, n'est pas?

Drain often, well probably not, but definitely every few years.

I've done my research and am a big proponent of synthetics -- pure synthetics, that is (blends are a waste of money).

Cold climates will see greater benefits from synthetics, particularly in the tranny. Shifting will be easier and less like rowing in chilled molasses. Synthetics are over-kill in protection, especially when it comes to sheer and heat stresses that break down conventional oils more quickly. They also have superior detergent qualities and do a far better job at keeping an engine clean...sometimes too clean if used after a conventional oil that has plugged some leaks. Their downside is that if there's a leak then synthetics will find it. Todays synthetics are PERFECTLY FINE with use in old-technology engines. Because synthetics don't break down easily their change intervals can be double to triple of the conventional oils. Filtering, of course, should be changed at manufacturers suggested intervals.

I believe GL-4 oil should be used, not GL-5 as it is known to "attack" (for lack of a better word) the yellow metals (e.g. brass & bronze). This is true for air-cooled VW 4-speed transmissions. I know my 914 tranny has VW stamped on it in various places inside and out but it's also considered a Porsche so I could be wrong about the GL-5 spec but I know GL-4 has been around longer than GL-5.

When I bought my used Jetta, I dyno'd her with conventional oil (engine) and the tranny's original synthetic. I then changed out the engine and tranny oils with synthetic (fresh synthetic for the tranny to be specific). Dyno'ing the car again netted me a 5hp increase simply by switching to synthetics. On average, my mileage went up 2 points as well...and I don't drive my Jetta like a grandma by ANY stretch of the imagination; I'm always pushing her. This simply confirms what's already known about synthetics, that they have superior friction reduction compared to conventional oils. Thus power & mileage & longevity are all increased by using pure synthetics.

I know for sure my 901 did not like Redline. I now have Mobilube SHC in it and it's much smoother than with the Swepco it had originally. Mobilube SHC is not M1 gear lube, it's one step above and hard to get. The big rig shop next door gets it in 55 gal drums, so it's easy for me. That's the only way to get it other than from Lufteknic (they somehow have it in gal jugs!).

We have an understanding problem here. Again. GL4 is GL4. GL5 is GL5. GL5 is NOT a newer, improved version of GL4. GL4 is NOT an older version of GL5. It's just DIFFERENT. If you needed a cylinder head for a Ford, you wouldn't buy one for a Chevy (unless the counter guy was REALLY persuasive!). If your name is "Joe", you don't spell it "B-O-B". Sure, they're letters, just not the RIGHT letters. If you have a tranny that uses GL5 (and you DO), you wouldn't put an oil with the WRONG specs into it. Well, you might, but you'd be causing it harm. Porsche trannies for air cooled cars from the early 50s until the introduction of the G50 didn't utilize brass synchros. Porsche specified GL5 because it is MORE SUITABLE for use in their gearboxes.

As for synthetic oils, strong anecdotal evidence indicates that synthetic oils tend to hemorrhage from well used VW and Porsche engines. I can't say synthetic gear oils do the same, but you again need to check the specs before you purchase any.
Same goes for aftermarket "friction modifiers". You add a tube of moly additive to your Porsche tranny and, sooner or later, it'll grind on every shift. You DO NOT want reduced friction in a Porsche tranny, because the synchros operate on friction. The Cap'n

Thanks Capt., I stand corrected on the GL-5 spec.

The only thing that I have a question about is that we DO have brass shift forks that ride on the synchro sleeves. Will the addition of the wrong synthetic (not good for yellow metals) allow these pieces to wear faster?

Forget the "yellow metals" already! GL4 is "yellow metal" friendly. GL5 is not. Porsche specified GL5, so they obviously didn't think that was an issue. I have yet to see brass shift fork wear not caused by something else being wrong. The Cap'n

GL-5 was known to be less friendly but some manufacturers may have changed their formulations. From the product web site of Amsoil they state their GL-5 can be used in GL-4 specified gear boxes. CITGO states their GL-5 can be used in manual trannies that specify GL-1 thru GL-4.

From the GL-4 spec at Pensoil:
"It is formulated to be compatible with copper containing alloys and soft metals found in synchronizers."
This was not mentioned in their GL-5 spec sheet. So I'd say that Penzoil gear oils need to be checked for the specific GL rating.

Just www.google.com and do a little reading

edit:
Royal Purple, for those that use it states:
"Severe Service Performance. Max-Gear® exceeds Eaton's stringent GL-5 / MIL-L-2105D Gear Oil Specs. Max-Gear® also is safe for GL-4 applications or bronze synchro gears."

I, run 90w with Whale Sperm

So, hypothetically, say someone new to 914s wanted to check their transmission oil level, borrowed the right socket (what's that type of socket called?) and couldn't find the transmission drain plug even after looking at the pics in Clymmer and lack of pics in Haynes... where would he look?

"someone" eh?

You need a 17mm 6 sided allen wrench or socket. Many have adapted bolt heads in various ways.

The drain is the lower plug and is on the right hand side. Above it is the fill and it is the same.

DO NOT REMOVE the drain plug before you have removed the fill plug. Why? Because you may not be able to remove the fill plug and then you will not be able to fill your tranny with any ease. Fill to the level of the fill plug with the car level.

Do you need pics? I can scrounge some up if no one else has some.