I'm sure if my trans was chewing itself up and I switched to a given oil that cured the problem I'd be pretty stoked about it as well. Glad you fellas found a solution

I just tracked my car with motul in it because that's what the porsche race shop uses exclusively and didn't notice anything unusual. FDs making decent power tend to burn up transmissions pretty quick on road courses so the smart bet for us track guys is likely to add a trans cooler as I don't think any fluid will prevent an early death.

 

I agree Dave but when Peter says something I listen and I really think he was onto to something that you're more likely to grind with a synthetic vs a dino gear oil. He also mentioned that it gets worse over time. I'm running around in a couple of low mileage cars. One with 36k miles and the owner used redline and it shifts ok and the other car has 14k miles using factory oil and it is smooth as butter. Could be the mileage and it could be the gear oil or driving styles but the lower mileage car w/ factory gear oil feels a lot better.

 

Agreed. I don't think the intent of this thread was to condemn all synthetics in the Mazda/FD trans. I noticed a long term issue with:
1. a FD trans that mostly used Redline and saw lots of track duty.
2. a Miata trans that didn't see much track duty but had much longer change intervals.

My local Mazda race shop that does trans rebuilds, has noticed an issue with various Mazda trans that ran Redline. Redline is probably the most popular synthetic gear oil so it is unlikely that these race shops have had the opportunity to compare results with other synthetics.

 

I've got another data point for this thread.
62K original tranny with dino oil all its life. Slight 5th gear grind on quick shifts otherwise smooth as butter.
Changed to RP 75/90 for impending track duty and was greeted with a slight grind in second, notchy shifting in all gears until really warm and a bad grind in 5th.
Drained the RP and poured in some Amsoil 75/90, no change.
Drained Amsoil and tried a little voodoo juice from my DSM days. One quart Valvoline 75/90 and the remaining fill with Penzoil Syncromesh. Very smooth shifting even when cold and reduced the original grind in 5th to almost nothing. After ~ 2.5K track miles. I still run the mix and won't be changing anytime soon.
My 2 centavos, YMMV.

 

yes, we should be clear that it was Redline in my tranny and Peter pointed that out and then he extrapolated to all synthetic. I have never run any type of synthetic since then.

 

First off, RP absolutely sucks. Little question it is the worst synthetic oil product on the market.

Second, on many occasions, I've heard of problems cropping up when a transmission is neglected (i.e. the user changes the oil every 50k or whatever) then all of a sudden the owner decides to get with the program and start changing it. Change it every 15k and use a good synthetic from the jump, my FD has 85k on it and shifts great (original trans).

Don't forget to change your diff fluid, too.

Note on synchromesh
http://www.teamrip.com/manual_transm...tion_info.html

While it has been found that the Synchromesh/Synchroshift type oils can sometimes improve the effectiveness of the synchronizers, allowing for faster shifts at higher rpms, this oil does not have enough film strength to ensure long gear and bearing life for the Mitsubishi transmissions.

Synchromesh/shift type oils are used in transmissions that are found in low torque applications that don't ask much from the oil in regards of film strength. Transmissions that call for Synchromesh type gear oils are designed with wide gear shaft spacing which greatly reduces the force on the gear teeth and large bearings so that they can used these low film strength oils. The reason behind it is to reduce parasitic frictional losses and to improve shift quality.

If you have a weak synchro, you may want to try the “Synchromesh/Synchroshift” type oils. However, it is our strict recommendation that you use the proper GL rating that the transmission was designed to use. Check your owner's manual for this information.

 

Agreed, but you have to start somewhere. Most FD owners don't bother with any of it.

 

Haven't tried Neo yet, but it seems to generate glowing reviews

http://www.imazda.com/forums/showthread.php?t=13352

The problem is that "buttery shifting" does not always correlate to what's best for your trans, in terms of overall longevity. Once again, subjective comments are of little help in these debates

 

All GM T56's come filled with syncromesh and that's all that's recommended for changes.... and I'd hardly describe an LSx motor as a "low torque application."

My Cobra's T56 is currently filled with syncromesh, and there was a definite noticeable change in shifting smoothness from the change. I'm have ~10k miles on the fluid, so I have no long term reports, but that is the fluid that a lot of people change to in their Cobras to reduce some of the T56's notchiness, and I have yet to read anything stating that it causes problems.

Obviously I have no relevant information on the FD tranny and syncromesh, but I saw that quote and wanted to make note of it.

 

Your opinions have been noted rice.
I wouldn't call 400lb/ft to the tires in an AWD vehicle "low torque" though. I know John at TRE and have used his parts in a few of my DSM trannies. I value his opinion but would ask that you read this as well.

http://www.sheptrans.com/faqs/index.htm
What gear oil should I use?
There are several gear oils that will work depending on horsepower or intended use. For most transmissions we recommend Redline MT90 or Pennzoil Synchromesh. For drag use or high horsepower cars please contact us

If you find anyone rebuilding/upgrading transmissions anywhere in the U.S. that's more knowledgeable than Shep I salute you sir.

This thread, like many others regarding oils will probably die an ugly death. I was merely adding a data point and some,IMHO, relevant information.

Happy boosting!

 

It's not hogwash. Synchros work on friction and friction changes when you use synthetics, change viscosity, and/or change additive formulations. MT-90 is similar in viscosity and additive formulation to basic mineral oil but it's synthetic and therefore you can't avoid the lower friction. When I had read Peter's commentary on synthetic gear oils 2ndhand before, I understand this point if your concern is shift quality, especially when you're referring to synthetic gear oils in general. Most gear oils available off the shelf are not suitable for synchronized transmissions. Many state they are not for use in synchro transmissions right on the bottle. I'm sure a great number of cars came into Peter's shop with these types of oils and I'm sure that has a lot to do with his opinion. As it stands now I personally use only Amsoil MTG and Redline MT-90 because they have the right viscosity and have synchro-friendly formulations. Not much else I would even consider putting in my FD trans.

(I would consider Pennzoil Synchromesh but the viscosity is lower than recommended and I'm not willing to compromise bearing/gear protection to try it)

Another thing to note is the exact product. "Redline" means little because they are a brand name with several gear lubes in the 75w-90 viscosity range. These products range from MT-90 (recommended IMHO for this application) to Shockproof (bad idea).

Another factor for you to consider Fritz is past owners' driving habits. The correlation between "mods" done to a car and the amount of hard driving done by the owner is pretty strong. The odds are good that the car with Redline was driven harder than the other one. In fact they might have banged up the trans and replaced with Redline hoping it would help make it shift better again.

The performance of a gear oil w.r.t. gears and bearings cannot be determined by driving the car. UOAs can show it if you're willing to go through several tests and trending. Synthetics excel at reducing wear and friction in gears and bearings and I would need to see some pretty compelling evidence to even consider that a mineral might do better in this regard. Said another way, I've yet to see a mineral oil compare to the performance of a synthetic in gearing and bearing applications.

David

 

If you like the way the car shifts with synchromesh, you may as well keep using it, but I would keep an eye on the viscosity. Get a VOA and a UOA. What is your change interval?

 

How frequently do you change it?

 

Rice I think you may have touched on something we might be taking for granted in this debate, change interval. I change mine every other oil change or around 4K. I track mine often though

 

I don't drive many miles with my FD, and what I do drive is pretty intense. So if I was street driving it, I'd change gear oils at 20k. As it is now it's been between 5k- 10k for my gear oils.

David

 

My Spec Miata buddy and I run SWEPCO 201 with no issues, but we do change it after every other DE weekend.

The original tranny finally started making noise at 115K-miles on the input-shaft bearing, so we just put in a JDM tranny from Fritz with new SWEPCO 201 . . .

Swepco has incredible "sticktion", that is, it has really great gear climbing capabilities, which works great on the synchos and rotating bearings.

:-) neil

 

Never heard of Swepco, has no reputation. It's generally good practice to avoid these off-spec, no-name oils. I think people use them because they want to feel like they have some kind niche, but the firms spending the money on R&D have the best products.

 

Yep, I've heard good things about swepco.

Just wanted to clarify that I'm using the Porsche OEM stuff now not motul. I think it's mobil delvac (big trucks and racers like it and apparently porsches) most likely a GL-5 oil.

I think the real key is go easy on the trans because the FD syncros aren't the best and use a good quality synth and you should be fine. Most gear oils today from big name companies are probably fine whether they are GL 4 or 5. Whatever ingredient in years past that was wearing/coroding the yellow/brass type syncros has been removed.

 

Sounds like cut-and-paste from a marketing brochure - means nothing. Get a VOA and UOA and present your case, otherwise, forget it.

 

Are they brass?

Based on?

 

http://www.redlineoil.com.au/Uploads/Downloads/MTL TR 02_03.pdf

 

My limited non technical dumbass thoughts were that GL-5 oils were bad for the syncros and I don't know what they're made out of and frankly don't give a damn but I'll leave it to you scientist to keep me informed however they better not be made of gold because I just sold one for 50 bucks

My inner chi told me the newer gear oils don't have the syncro degrading formulas any longer

 

Differing opinions

http://www.bobistheoilguy.com/forums...&Number=948087

Mobil claims their synthetic gear is GL-5 rated and will not corrode yellows
http://www.mobil.com/USA-English/Lub..._LS_75W-90.asp

+1 for Howard

Do you really need a GL-5 rated oil in a transmission - except for racing?

http://www.ferrarichat.com/discus/me...tml?1057714321

"I have seen oil related corrosion of yellow metals in 2 Fiats and one Alfa Romeo (sorry no photos)and a number of years ago experienced problems (twice) with Mobil synthetic gear oil in a Fiat gearbox - the product is different now and I haven't tried it. But there's no yellow metal synchros in a 308 so I can't see a problem there.

 

LOL. Are you kidding me?

Swepco has been around forever. Just because you aren't aware of it, doesn't mean it doesn't have a 'reputation'.

Swepco is mostly used in real race cars and cars that see a lot of track duty driven by people who are aware of their options. So is Motul for that matter.

I don't necessarily buy into the info in Ferrari Chat link. The author is a doctor (surgeon I believe). Thinking he is some kind of authority on oil just b/c he wrote a long article is a bit twisted. I respect the info he shared and I believe some of it but given the author's field of expertise (vs his chosen hobby - expensive cars and oils) I take it with a grain of salt.

 

LOL....you have a care free life, Fritz