Which tranny oil is best?

daveimme · daveimme's Garage

I want to change the trans oil in my car, but not know what to put in there.

I used to run redline in my 88 BMW auto and it made a huge difference, so I would say I am leaning towards Redline, if there is an application by them that someone can vouch for? Tranny fluid is cheap.....compared to transmissions, so I will not shy away here from a proven product.

Anybody want to chime in? I hate making expensive mistakes!!

rammstein · 09-23-2003, 10:08 AM

Well, my mechanic suggested the following- the swepco is the best, especially for hard use. Its thick. But, he told me that driving around town, and when its cold out, that perhaps Mobil1 Tranny fluid is best. So at the moment, I am using the Mobile1. But the Swepco is a pretty cool blue color

Seriously though, when I put in the Mobil I could feel the shifts get smooth much sooner after startup, meaning the fluid was ready to go at a lower temp.

No matter what, changing it regularly is probably far more important that what you use anyhow.

daveimme · daveimme's Garage

Well, down here in the south (Louisiana) it rarely ever freezes...and if it does, it never lasts long. Heat. It is hot down here.....today is an exception though (85 degrees) abnd Fall is coming, so having said that, I'm leaning towards Mobil 1 still good?

I will admit that I have never, ever changed the trans fluid in a manual shift car. To add more ignorance to this, I thought it was never necessary, either.

SO....WHICH Mobil 1 oil for the tranny do I look for? I can find out from the dealer what the capacity is....

SoCal Driver · SoCal Driver's Garage

Not only is changing the trans lube a 30,000 or 60,000 maintenence item repacking the CV's and axle bearings are too.

guinnastysassy · 09-23-2003, 10:36 AM

i use redline, but it is expensive

rammstein · 09-23-2003, 12:52 PM

Just go to the auto-store, they only have one kind of Mobil1 tranny fluid far as I remember. I don't have my Porsche Manual handy at the moment, but if you have one it will recommend the weight. From the top of my head, I think I used 85. Someone else will surely chime in. If you have never changed your fluid, you'll feel the difference instantly.

Oh- You will also need a 17mm Hex Socket for the drain plugs, probably will want to soak the drain plugs in WD40 for awhile before trying to loosen. Alsom remove the top first, then the bottom. Great advice I got, keeps you from draining your fluid and not being able to refill. And that brings me to the last point. Be sure you have a pump-device to refill. It is not possible to just pour it into the sideways hole. Unless you are God.

The bonus of synthetic tranny oil is it doesn't smell nearly as nasty as Dino oil.

Mark_944S2 · 09-23-2003, 01:17 PM

Redline 75/W90 NS.

The NS gives a better shift as long as you have no LSD. Do not use NS with an LSD.

Improved shift in my S2 no end.

Mark

speedracing944 · speedracing944's Garage

I used Mobil 1 when I refilled mine. I think it took about 3 quarts if I remember correctly. I use Mobil 1 motor oil also but notice my oil consumption is slightly higher. Anyone else experiance higher oil consumption with using mobil 1 verses dino oil?

rammstein · 09-23-2003, 01:38 PM

If you have a slight leak and replace Dino oil with Mobil1, it can exacerbate the leak somewhat. From a given hole, more mobile1 will come out than Dino. Since I had all my oil leak problems fixed, (cross fingers) I haven't noticed any loss of oil at all. I waited until then to use Mobile1, cause it would have ended up on my driveway.

daveimme · daveimme's Garage

I know and trust redline, so that will work for me.

I'm gonna get it..... I'll check redline's site and peruse their info....

1.2gees · 1.2gees's Garage

I use redline shock proof racing gear oil, seems to give the best response when shifting while driving hard... But, there's other oils that keep the transaxle quieter, and smoother when cold (like swepco, or mobil 1). This is on a 200k gear box, but there's a funny noise coming from back there at slower speeds (hoping it's a stub axle/wheel bearing though)!
Ahmet

highboost951 · 09-23-2003, 02:21 PM

I'm located in Southwest Missouri and we have extreme temperatures on both ends of the scale. I prefer Amsoil series 2000 75W90. We've had syncro problems when using redline in the race cars at high temp and swepco is absolute crap in the cold. Like swepco, amsoil is blue too but the stuff pours like water vs. swepco's sticky stuff and it still has extreme cold and hot capabilties. I've used redline, swepco, and mobil one, I like amsoil the best since it's great in both the heat and cold.

1.2gees · 1.2gees's Garage

Highboost, my comments concerning "cold" are no colder than say 30 degrees, if that. BTW, have you ever used redline's shock proof racing transmission fluid? It is a weird florescent greenish in color.
Ahmet

Roger Hall · 09-23-2003, 04:49 PM

My mechanic swears by Swepco. I was thinking about Redline but he talked me out of it. He said that Redline has not updated their formula in years. The Swepco really quieted my tranny noise.

Dantilla · 09-23-2003, 04:59 PM

All the 911 guys swear by Swepco. That's what I use.

1.2gees · 1.2gees's Garage

Does your mechanic's supplier only cary swepco? I'd look into that...
Ahmet

newoldguy · 09-23-2003, 10:08 PM

I'm using Mobil 1 75W-90. They also make a 80W-140 which would be too thick for our cars. As others have noted, it made a BIG difference in the shifting of the transmission.

daveimme · daveimme's Garage

Hmmm, Swepco is like 35 bucks a gallon, huh? I haven't checked capacity in the gear box yet, though so I wonder how much it holds?

rammstein · 09-24-2003, 07:49 AM

I've done mine twice- both times to fill it I just kept pumping in oil till it started spilling out. Took ~ 2.5 liters. Make sure you have 3 liters to be safe.

VT944 · 08:50 AM

1.2gees, we use redline's shock proof racing transmission fluid in our rally cars. The stuff is *very* messy when you rebuild, but it works very, very well.

We had a driver run two stages with NO tranny fluid, and he actually made it through! That was pretty incredible to us, considering the abuse the cars take. The case got cracked, and he lost all tranny fluid. When we tore down the tranny after the event, there was still a coating if shockproof on everything - which is the only reason the tranny lasted that long with no fluid.

We run dog boxes, but that makes little difference. Our tranny's are very strong, but would never be expected to last two stages with NO fluid. The shockproof sticks to EVERYTHING!

We rebuild out transmissions every 200/300 miles, but the cars are run very hard. I have no experience with the shockproof in a street/autocross car, or transmission with hign miles.