Sychro Grind - new trans fluid
06-21-2009, 09:36 AM
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Sychro Grind - new trans fluid
I am hoping someone can help me with what I have been experiencing on the track...and not when the car gets very hot on the road...
I changed my transmission fluid from OEM, and since then been getting a grind between 3rd and 4th (@ Watkins Glen running Redline MT90) and 4th to 5th (@ Gratten running Valvoline Synthetic). It is quite repeatable and always in those specific gears...and not in any other gears.
At the beginning of sessions, there were no issues. As the day went on, and it got hotter, it started to show up and then get more repeatable.
What are people using out there?
I changed my transmission fluid from OEM, and since then been getting a grind between 3rd and 4th (@ Watkins Glen running Redline MT90) and 4th to 5th (@ Gratten running Valvoline Synthetic). It is quite repeatable and always in those specific gears...and not in any other gears.
At the beginning of sessions, there were no issues. As the day went on, and it got hotter, it started to show up and then get more repeatable.
What are people using out there?
06-21-2009, 10:59 AM
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People have used a number of different fluids and, if you look in the tech/issues and problems area of this board, you'll find a very complete thread on the subject.
Bottom line is that RX8 transmissions are not exactly robust and if you've done sufficient damage to the synchro rings, you've probably also done additional gear damage, have metal circulating in the trans and are on your way to a replacement.. Not to be a downer, but that seems to be the experience many of us have had with the '8 transmissions.
You may be able to alleviate the grinds, short term, by going to another fluid...which is worth a try if your car is off warranty...but, once these transmissions start exhibiting the behavior you've described, it is usually indicating internal damage that isn't going to fix itself with a change in viscosity or additives in trans fluid.
Bottom line is that RX8 transmissions are not exactly robust and if you've done sufficient damage to the synchro rings, you've probably also done additional gear damage, have metal circulating in the trans and are on your way to a replacement.. Not to be a downer, but that seems to be the experience many of us have had with the '8 transmissions.
You may be able to alleviate the grinds, short term, by going to another fluid...which is worth a try if your car is off warranty...but, once these transmissions start exhibiting the behavior you've described, it is usually indicating internal damage that isn't going to fix itself with a change in viscosity or additives in trans fluid.
Last edited by mwood; 06-21-2009 at 11:02 AM.
06-21-2009, 11:59 AM
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Mine started to grind going into 5th; either up from 4th or down from 6th. I changed the tranny fluid from the factory fill to RP MaxGear 75w90 at around 5,000 miles.
The dealer replaced all of the tranny parts except housing and shaft under warranty. Problem solved. I've read that MaxGear is not good for our transmissions and it seems that Mazda changed the gear oil spec from GL4/GL5 to just GL4 somewhere around 2006.
Note to self; go with GL4 fluid from now on.
The dealer replaced all of the tranny parts except housing and shaft under warranty. Problem solved. I've read that MaxGear is not good for our transmissions and it seems that Mazda changed the gear oil spec from GL4/GL5 to just GL4 somewhere around 2006.
Note to self; go with GL4 fluid from now on.
06-21-2009, 12:13 PM
#4
i use the mt90 in my second transmission and it works better than any other oil i tried before. Somebody uses the castrol taf-x too with good results.
I love how the tranny feels with shell's transaxle oil when very hot but, beside it being a gl5, it sucks for daily driving in the transmission. You really need to bring the thing up to good operating temps to like it.
I love how the tranny feels with shell's transaxle oil when very hot but, beside it being a gl5, it sucks for daily driving in the transmission. You really need to bring the thing up to good operating temps to like it.
06-21-2009, 12:25 PM
#5
https://www.rx8club.com/rx-8-racing-25/just-how-many-people-have-had-transmission-issues-157476/
I took TeamRX8's suggestion, and have been using Redline 75W140NS.
If it was available locally, I would have considered ULLLOSE's Power Pure stuff.
I took TeamRX8's suggestion, and have been using Redline 75W140NS.
If it was available locally, I would have considered ULLLOSE's Power Pure stuff.
06-22-2009, 11:48 AM
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https://www.rx8club.com/showthread.php?t=157476
I took TeamRX8's suggestion, and have been using Redline 75W140NS.
If it was available locally, I would have considered ULLLOSE's Power Pure stuff.
I took TeamRX8's suggestion, and have been using Redline 75W140NS.
If it was available locally, I would have considered ULLLOSE's Power Pure stuff.
Last edited by altiain; 06-22-2009 at 11:51 AM.
06-22-2009, 08:02 PM
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How long ago have you replaced your fluid? I am asking because when I replaced my royal purple maxgear with redline mt-90, the shifting became a little notchier in the beginning. After 2k-3k miles, everything became butter smooth. Maybe it just takes time for the fluid to break in...
06-23-2009, 08:59 AM
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I'd really like to see some hard evidence to back up the assertation that NotAPreppie made. Has Mazda changed the documentation in the owner's manual? I know there has to be at least one '07+ owner lurking this thread - would you mind looking in your owner's manual and actually telling us what it says?
Last edited by altiain; 06-23-2009 at 09:08 AM.
06-23-2009, 12:06 PM
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How long ago have you replaced your fluid? I am asking because when I replaced my royal purple maxgear with redline mt-90, the shifting became a little notchier in the beginning. After 2k-3k miles, everything became butter smooth. Maybe it just takes time for the fluid to break in...
06-23-2009, 09:25 PM
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I think it's more a case of "monkey see, monkey do". Someone somewhere said "GL-5 is teh bad", and that has been repeated over and over again with no evidence to back it up. If you read it on teh intarweb it must be true, right?
I'd really like to see some hard evidence to back up the assertation that NotAPreppie made. Has Mazda changed the documentation in the owner's manual? I know there has to be at least one '07+ owner lurking this thread - would you mind looking in your owner's manual and actually telling us what it says?
I'd really like to see some hard evidence to back up the assertation that NotAPreppie made. Has Mazda changed the documentation in the owner's manual? I know there has to be at least one '07+ owner lurking this thread - would you mind looking in your owner's manual and actually telling us what it says?
Page 10-4, section "Lubricant Quality".
Just downloaded it off of Mazda's website (had to setup a faux 2006 RX-8 in my MyMazda account to get it). I'm uploading it to my web host to save time. You are welcome to repeat my steps if you want to check my facts. I repeated for '08 and '09; only GL-4 listed, no GL-5. I'd imagine it's the same for '07 but somebody is going to have to ask REALLY nicely to get me to do the finger work on that.
Last edited by NotAPreppie; 06-23-2009 at 09:28 PM.
06-23-2009, 10:05 PM
#12
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I have an 07 and I'm looking at the manual and it says "API Service GL-4 (SAE 75W-90)". I switched to Redline MT-90 because it seemed well recommended on this forum at 35,000 miles because I'm tracking the car ~5 times a year. If anything the transmission is notchier after the Redline than it was before although not seriously so, it certainly isn't any better than what was in the car (unknown probably OEM because of the mileage). I am deliberate and methodical in my shifting on the street and the track and try not to rush it. When I replace the transmission oil I will probably try something else.
Last edited by justjim; 06-26-2009 at 02:00 PM.
06-25-2009, 01:39 PM
#13
do not use regular 75W90 gear oil in the trans, you need the Redline 75W90-NS or 75W140-NS for the transmission, the NS designation means it doesn't have differential limited slip additives in it, these additives cause synchro meshing issues in some transmissions
I have the Mazda RX-8 Transmission Service Manual, it states both GL-4/GL-5 fluid
Understand that I'm not saying all GL-5 fluids are OK, unlike the Redline "NS" gear oils most have limited slip and other additives, you can't throw them all in a box and claim they're all bad is all I'm saying ...
.
I have the Mazda RX-8 Transmission Service Manual, it states both GL-4/GL-5 fluid
Understand that I'm not saying all GL-5 fluids are OK, unlike the Redline "NS" gear oils most have limited slip and other additives, you can't throw them all in a box and claim they're all bad is all I'm saying ...
.
Last edited by TeamRX8; 06-25-2009 at 01:44 PM.
06-25-2009, 01:50 PM
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do not use regular 75W90 gear oil in the trans, you need the Redline 75W90-NS or 75W140-NS for the transmission, the NS designation means it doesn't have differential limited slip additives in it, these additives cause synchro meshing issues in some transmissions
I have the Mazda RX-8 Transmission Service Manual, it states both GL-4/GL-5 fluid
Understand that I'm not saying all GL-5 fluids are OK, unlike the Redline "NS" gear oils most have limited slip and other additives, you can't throw them all in a box and claim they're all bad is all I'm saying ....
I have the Mazda RX-8 Transmission Service Manual, it states both GL-4/GL-5 fluid
Understand that I'm not saying all GL-5 fluids are OK, unlike the Redline "NS" gear oils most have limited slip and other additives, you can't throw them all in a box and claim they're all bad is all I'm saying ....
Last edited by justjim; 06-26-2009 at 02:01 PM.
06-28-2009, 01:54 AM
#18
what does WRT mean?
I use the mt90 and i find it to be the best oil i ever put in my transmission after the swap. It is also pretty cheap here since we have an official importer
I use the mt90 and i find it to be the best oil i ever put in my transmission after the swap. It is also pretty cheap here since we have an official importer
06-28-2009, 02:03 AM
#20
I tried it but on another car so i don't think that counts
The notchy transmission you experienced with the mt90 is what i felt while using the shell transaxle oil,a gl5 oil. It is horrible with a cold transmission but is very good when it warms up.
The mt90 doesn't seem notchy at all to me!
Why would you recommend the 75w140ns instead?
The notchy transmission you experienced with the mt90 is what i felt while using the shell transaxle oil,a gl5 oil. It is horrible with a cold transmission but is very good when it warms up.
The mt90 doesn't seem notchy at all to me!
Why would you recommend the 75w140ns instead?
06-28-2009, 02:05 AM
#21
shifting issues and mutiple blown trannies without, none with ... and cold notchiness/grinding is what I got with MT-90
MT-90 is simply a 75W90 GL-4 oil, both oils are 75W when cold, why would you object to additional viscosiity when the trans gets uber hot under extreme loading?
MT-90 is simply a 75W90 GL-4 oil, both oils are 75W when cold, why would you object to additional viscosiity when the trans gets uber hot under extreme loading?
Last edited by TeamRX8; 06-28-2009 at 02:08 AM.
06-28-2009, 10:09 AM
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The without is with the 75w140NS.
I haven't used the MT90, so I won't offer comparisons, but I don't have any issues with the 75W140NS when cold. Like Team said, both oils have the same cold viscosity.
My car also ran flawlessly last weekend at Eagles Canyon in 95+ degree ambient heat on a track that requires about 20 shifts per lap (mostly long straights coupled by 50 mph hairpins) with the 75W140NS. We'll see how long it holds up, but so far the car seems to like this oil better under extreme conditions.
I haven't used the MT90, so I won't offer comparisons, but I don't have any issues with the 75W140NS when cold. Like Team said, both oils have the same cold viscosity.
My car also ran flawlessly last weekend at Eagles Canyon in 95+ degree ambient heat on a track that requires about 20 shifts per lap (mostly long straights coupled by 50 mph hairpins) with the 75W140NS. We'll see how long it holds up, but so far the car seems to like this oil better under extreme conditions.
06-28-2009, 06:24 PM
#25
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Team you never answered my question. What is the difference between MT90 and the 75W140NS? Is it just viscositiy or are there other additivies, differences? Also what the hell is WRT? I haven't looked but is the 75W140NS widely available?