Transmission Flush

[chitowndad]

Guys,
I'm setting up my winter projects (doing the research now) and I want to flush the manual transmission on my 01S. I've seen a couple posts that were from 2005-2006 about using 3 qts of Redline MT90.

I once had a 1991 300ZX (loved that car) and I changed the transfluid on it several times. I started with Redline MT90, then Royal Purple and then a thinner weight Redline. Since my 300ZX had synchro issues (clucking in 2nd), the thinner Redline did the job... On the 300ZX the fill plug was on the top of the transmission and the drain was on the bottom, which was real easy to find.

Does anyone have a link to the manual transmission flush, specifically the drain and fill plugs?

Would you recommend 3 qts of the Redline MT90 for the Boxster?

My Boxster is 2001S with 11K mikes and has never had the transmission flushed. It's a little sticky shifting when the engine is cold but is ok when warm.

Any insight is appreciated.
-Steve

[chitowndad]

Nevermind, I think I found what I was looking for on this thread:

http://www.renntech.org/forums/index.php?showtopic=7060

-Steve

Where do I find the special tool for the transmission drain plug?

[Lil bastard]

Originally Posted by chitowndad

Where do I find the special tool for the transmission drain plug?

http://www.zdmak.com/wbstore/main.asp?action=PROD&PROD=MK-3357&CTMP=1

[chitowndad]

Thanks! That was easy!

-Steve

[jmatta]

Is there an advantage to changing trans fluid at such low mileage? The maintenance schedule puts the fluid change at 90k miles, but says nothing about length of time. My '02 S has slightly more miles than Steve's (15k) and was just curious.

[Lil bastard]

There really isn't an advantage to changing the tranny fluid 'early' unless it's to upgrade to a better fluid. Tranny fluid operates in a 'closed' system and isn't subject to the type of breakdown motor oil is - no fuel or combustion products to mix with it. Also, tranny fluid actually works a little better once 'aged' a little.

In cars w/ yellow metal balks/synchros, changing too frequently can actually hurt these parts because when new, tranny fluid can slightly attack these parts, but once it starts to break-in, it undergoes a chemical change which is more friendly to the internals. Tranny fluid contains a lot of sulphur compounds to better withstand compression and shear and these breakdown over time which is why used tranny fluid has that strong 'rotten egg' smell to it.

The service interval is spec'd to the type of fluid used - to switch it before it becomes too acidic and to drain any fine metal shavings (normal) which have accumulated at the drain plug (usually magnetic). These s/b a fine paste, not actual chunks. If you find 'chunks' see - Troubleshooting...lol!

But, there are probably better fluids out there than OEM MB1. Redline MT/90 is a very good fluid and while I've not personally used Royal Purple tranny fluid, I have a lot of respect for their products too.

When changing, be sure the tranny is warm which means a 10-15 min. run prior to draining it (90W takes a bit of time to warm), the fluid s/b Hot so be cautious.

Also, be sure to open the Fill Plug BEFORE draining it! Not only will this ease the draining, but if The Fill Plug's siezed, or the threads galled, you don't want to find this out after you've already drained it, you want to be CERTAIN that you can refill it.

[chitowndad]

While I only have 11K miles, my car is 7 years old so I'm thinking that I should change the original tranny fluid and original antifreeze. When it's cold the shifting is a little stiff. I've used Redline and Royal Purple before and what you use depends on the mileage of your car. I'm thinking of still replacing it this winter...

-Steve

[saaber]

Originally Posted by chitowndad

3 qts of Redline MT90.
-Steve

I tried redline in my 00' S and it didn't shift smoothly. I tried different mixes/weights of redline also (75W90 NS, MTL, etc.). I have had fantastic luck with redline on other car trannys (many makes) but for the S the only thing that shifted well for me was the original fluid form the dealer.

[blinkwatt]

DON'T TRY ANYTHING OTHER THEN OEM STUFF ON 986 S 6-SPDS. I've had Swepco 201 in mine which I was promised by the local Porsche Racing shop and other indy dealers that it's the best stuff out there for Porsches. That may be true on other Porsches not the M96 6-spds though. It's a pain to shift when the tranny is cold. Once it's warm it's fine but I hate when it's not warm. I will be switching back to OEM when I have the time.

I've seen good stuff on Redline MT-90 on 6-spds though. Personally on my 5-spd I loved the MT-90 but after thsi Swepco 201 on the 6-spd I'm going to back to OEM for good. Lol the Swepco stuff was twice the price of OEM as well.

[chitowndad]

Really? I was about to order 3 qts of Redline MT90. I liked Redline on my 300ZX but if you guys think OEM is better, I'll reconsider.

When it's cold my shift is stiff but not that bad so I guess I'm either being too picky or looking for a winter project next month. I'll put the boxster up on stands for the winter months so that gives me plenty of time to mess around between December and March.

Thanks again, I'll look into OEM.

-Steve

[Kirk]

I changed mine at about 40,000 miles to Castrol synthetic. I did it early to clear out any metal shavings/particles in the oil - basically being conservative. I ran the Castrol for about 5,000 miles and didn't like it. Poor shifting when cold. At 45,000 miles I switched over to Mobil 1 and it's been okay, a little better.

Understand that you don't really "flush" the transmission so much as drain the old oil out and then put in new stuff, like an engine oil change.

I don't understand the question about the special tool to remove the drain plug though. Disregard what Lil Bastard posted - that tool is for the 5 speed transmission. With the 6 speed transmission from the S you just need a 10 mm allen socket (available at Sears, Harbor Freight, etc.).

Kirk

[chitowndad]

Thanks Kirk,
Ah crap, I ordered that tool and it comes in like 1-2 days so that was pissing $20 down the drain!

Oops.

-Steve

[roadracer311]

I changed the tranny oil on my 2003 Boxster S when it hit 20k miles in October of 2007.

I work on motorcycles for a living and often get to see what break-in oil looks like coming out of a bike. (it has sort of a pearly look to it from all the tiny metal bits). So, I thought it would be good to get the original stuff out of there in spite of the 90k mile service interval, just to clear out any of the metal that comes off as the gears sort of wear-in to each other.

I did a ton of research and ended up using Redline 75W90 NS. The shifting feels the same as before. Possibly a tiny bit better, but definitely not worse. (Having raced motorcycles for 5.5 years, I'm fairly sensitive to small changes in the vehicles I drive/ride. )

Before and after the oil change, the best thing I've found to keep it from crunching into 2nd gear is to make the 1st to 2nd shifts at 3k rpm until it's warmed up.

[Lil bastard]

Originally Posted by chitowndad

Thanks Kirk,
Ah crap, I ordered that tool and it comes in like 1-2 days so that was pissing $20 down the drain!

Oops.

-Steve

Hey, sorry for the bad advice! I should'a looked more clearly and seen you had a 6 Sp. Tell you what, see if you can sell it in the classifieds and if not within 2 wks., I'll buy it from you to square things even though I have a TipS...sorry again!

[chitowndad]

So the Redline 75W90 NS is a GL5 and the 75W90 MT is a GL4 oil. How big of a difference is the GL4 verses GL5?

-Steve

[chitowndad]

Thanks for the offer Lil Bastard but it just means I don't tell the wife and I don't buy lotto tickets one week! LOL ) I may put it on ebay, some day...

-Steve

[Cloudsurfer]

My understanding is that GL4 is not so good for gearboxes with yellow metal in them. I am not sure if the Box S does or does not, but I have been running 75W90NS in mine with great success.

I don't think any fluid will make these boxes shift like butter when cold, but I certainly don't think its any worse than stock with the 75W90NS and I'm inclined to think its a better lubricant than the OEM stuff.

[Kirk]

Originally Posted by chitowndad

Thanks for the offer Lil Bastard but it just means I don't tell the wife and I don't buy lotto tickets one week! LOL ) I may put it on ebay, some day...

-Steve

Eh... just throw it in your toolbox. You'll probably need it someday for a different car or a friend's car. It's not like the tool is going to go bad or anything. I've got lots of tools that I barely use, but then the one time you need it... well you need it!

Kirk

[FTD]

Originally Posted by roadracer311

I changed the tranny oil on my 2003 Boxster S when it hit 20k miles in October of 2007.

I work on motorcycles for a living and often get to see what break-in oil looks like coming out of a bike. (it has sort of a pearly look to it from all the tiny metal bits). So, I thought it would be good to get the original stuff out of there in spite of the 90k mile service interval, just to clear out any of the metal that comes off as the gears sort of wear-in to each other.

Is there a 'pan' for the transmission oil, whereby it can be dropped and the area around the magnet that is supposed to catch the metal particles can be wiped clean?

[Lil bastard]

Originally Posted by FTD

Is there a 'pan' for the transmission oil, whereby it can be dropped and the area around the magnet that is supposed to catch the metal particles can be wiped clean?

There is for the Tiptronic - 4 magnets are placed in the pan to catch any shavings. If you pull the pan, you need to replace the gasket too.

But for the Manual, there is no pan, only the transmission case w/ drain/fill plugs. The magnet is in the drain plug.