Manual transmission fluid change???

I don't know about you guys, but unless my car is warm it is not too fun shifting it. First gear is fun to engage and 2nd is equally as notchy. I hate it soo much. I am debating changing it out. I have been doing some research on fluid, and Redline has some that supposedly helps this enormously. I have had experience in changing fluid out, and in zf transaxles, it made a huge difference to periodically change it, every 20k with sythetic. The result was buttery shifting hot and cold. Check this stuff out and let me know what your thought are. Also I am going to do the brakes and the 30k service at the same time. I am going to have the pads changed to pagid s, stainless lines, and ate super blue fluid. Any suggestions on keeping this bill down, at least for the 30k service? Thanks here is the link <a href="http://www.redlineoil.com/products.htm" target="_blank">http://www.redlineoil.com/products.htm</a> The two different ones that I am considering depending on which best matches the oem fluid weight and protection are the mt-90 and the mtl fluid. They are off manual transmission fluids, sorry it won't let me link it directly. Which would better match the oem fluid. I will go down to the car and check the manual but based on the descriptions otherwise which sounds better? Also I am planning on having them flush and change my radiator coolant/fluid. My car as it is now runs really hot compared to my friends new c4s. My car sit typically in the middle of the zero to the end of the zero of the 180 mark! I know it has to probably be retarding the timing and robbing power? I am going to also add water wetter to it if it still runs hot after the flush and change. fyi the car was from pennsylvania and as such was running 100% coolant I am sure so hopefully that is it right there! Please list your comments and suggestions to everything, especially you, LOren! Thanks everyone. Sean

Here are the factory recommendations for manual transmissions: Carrera Transmissions <img src="http://web.dsldesigns.com/~ljcook/images/transmission_oils.gif" alt=" - " /> Redline is also good, a good number of racers use it. Just be sure to get the proper weight. Coolant -- If you change the coolant be aware that any mixing with the organic Porsche coolant can cause the mixture to jell (as in Jello). For corrosion protection Porsche highly recommends their organic coolant (actually Elf brand). <img src="http://web.dsldesigns.com/~ljcook/radiator/images/coolant.jpg" alt=" - " /> If you are having cooling problems and you have cleaned the radiators then you may have another problem. If it is just under heavy driving then I would suggest a 3rd radiator. This is relatively inexpensive engine insurance (kit is under $500 from Carnewal.com). Here is a <a href="http://web.dsldesigns.com/~ljcook/radiator/index.html" target="_blank">link</a> to my installation.

Hmm. that is pretty cheap insurance. It is actually during normal driving where the temp sits in the middle of the 0 in 180. When I get on it hard it almost goes to the line of the next mark, I have to take it easy once I am there and let it cool a bit which is a real drag. I am having the dealer to the coolant thing. Do you think that I will have any problems with the water wetter if I add it to the oem coolant? Also I am still somewhat undecided and keep going back and forth between pads, hawk hp +, and the pagid s's. any thoughts? Thanks Sean

Have you ever considered that it might be the guage or temperature sending until and not running hot at all? In any case, the cooling fluid wouldn't cause this problem. I wouldn't change this unless you have a good reason to do so. Changing transmission fluids periodically is a good idea but pay close attention to the specifications. There are different types and it is easy to get the wrong type. A number of the better synthetics out there are the wrong type (for example, Mobil One synthetic is the wrong type). But they might still be preferable in the differentials (where there are no syncros) given their lower friction. Not sure about this.... There was some interesting discussion of this topic some months back so you might want to search. Stephen

I haven't considered that at all really. I will have the dealer check it out. The point about the tranny fluid is interesting do you remember the thread topic or search parameter? Thanks. Sean

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by SPR: <strong>...do you remember the thread topic or search parameter?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica"><a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=6;t=001035" target="_blank">Topic: Synthetic gear oil</a> Stephen

cool thanks.

Well according to the redline people the mtl seems to be the best fit off their website. It complies with 75w-90 weight and it also complies to gl4 type and not gl5 so it will not produce corrosion. I have sent an email to them in any event to get the confirmed skinny. Their friction charts and other measurements of comparison look phenomenal, and I hopt that the mtl will work, as it, if the charts are accurate shift as well cold as hot! I am excited! Thanks for the link btw, it was very helpful about the gl4/gl5 issues and weights.

You are welcome. Please report back after you've tried it a little. Stephen

Alright I just got a reply back from them, and really I don't know if it is all that credible? I would like to know your guys' thoughts. here is is... Sean Your Porsche uses a transaxle and the gear lube is shared between the transmission and differential. I would recommend a blend of one quart of the Red Line LightWeight Gear Oil and the remaining almost 3 quarts of 75W90NS. The Red Line GL-5 lubes are not corrosive to any brass, bronze or copper components. The MTL is a 70W80 GL-4 gear lube a lower viscosity and not a GL-5 as Porsche calls for. The 75W90 contains a friction modifier and can be too slippery for the synchros in the transaxle. I came up with this combination and evaluated it in my 993 C4S, it offers very good all around shiftability and good low temperature shift characteristics. Chatter from the limited slip when making a slow tight turn doesn't seem to be an issue with these units. Regards, Dave Red Line Oil What do you think? Should I try it or run it by my mechanic first? I think I will do that.

This all started because you said that you were having trouble shifting. Exactly what trouble? Maybe the solution is to learn to double-clutch the car? Thin out the oil and you'll have less protection. These cars produce a lot of power. I personally wouldn't want a thinner oil in my gearbox. I would happily put up with a little stiffness until it is warmed up. I certainly don't have any complaints about the shifting in my Turbo. Could it be a problem with the transmission itself? I wouldn't use a non-approved type and I wouldn't use an unapproved weight absent a very good reason. For one thing, doing so might leave you without a warranty if something breaks (see above suggestion that it just could be a problem with the transmission). Stephen

Double clutching from first at a dead stop? Please read the entire thread. Furthermore turbos have a different shifter/tranny and don't suffer from the COLD shifting problems that the others do, I am told this repetedly. I am obviously not going to use something that will void my warranty and of COURSE I will be checking with my mechanic before I even consider the purschase. Please read the entire thread before posting and have an adequate graps on the material. Thanks on behalf of I am sure everyone.

SPR, I appreciate the work you are putting into this investigation, as this is a real problem for me in the winter. The letter from Red Line Oil looks very promising; please let us know how this works out!

Yeah I definitely will. I will also inquire about the different areas for all of us, even though I live in CA, as there might be different temp changes with viscosity, i.e. below x degrees then it might not work as effectively as a friction reducer with the same amount of protection

Alright I just recieved this reply concerning my thought and worries about gl5 being corrosive, as well as the proper protection for the diff, and non slippery issues of such a friction modified synchromesh blend. Here is the reply The transaxle is basically the same design and I would recommend the blend in the '99. Some GL-5 gear lubes can be corrosive to brass, bronze or copper, but not the Red Line GL-5 gear oils. The 75W90 contains a friction modifier so could be too slippery for the synchros, so I wouldn't recommend that product. As an option you could use the 75W90NS plus about 1/2% friction modifier. Part of the intention with the blend is to make the shift as consistent over the temperature range as possible, the blend is close to the factory fill viscosity. Regards, Dave Red Line Oil So I replied once more just to get the exact amount of what to what. Hey Loren what do you think of this? I am very interested to run it by my mechanic as well as you before I try, but it seems pretty legit and persuasive.

The final suggested mix is: I would recommend one quart of the LightWeight Gear Oil and the remaining almost 3 of 75W90NS. I believe this is based on a capacity off a 993 c4s which was probably 4q v. 3q. This is supposed to give the same protection with almost the same friction co efficient or shift effort cold and warm!