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Switch to GM Synchromesh!

13K views 26 replies 13 participants last post by  rallymaniac 
#1 ·
Looking for a better fluid for my transmission, I didn't want to pay $14/quart for Motul, nor did I want to pay more than that for Neo Synthetic. I had tried Valvoline 75w90 and did not like it at all. I decided to try GM Synchromesh, which is not cheap ($10/quart) and it was available to me the same day. The car shifts soooo much smoother and is much quieter. I highly recommend trying this stuff. :thumbup:

Oh and if you have not bled your clutch, I did that at the same time and it feels ten times better. This is all at 28k miles.
 
#7 ·
If it's GL-5 tranny fluid it should not cause any prob's, I think I will bite the bullet and give it a shot!

I already have 4quarts of the Valvosludge to go in, But I keep hearing how nice the Synchromesh is.

So how is reverse?, It still take some "talking too" to get it in?

Thanks for the tip

Shotgun
 
#12 ·
I have an 02 WRX with the STi RA gearset. I am running the Motul synthetic and have yet to find a better oil. The list price like you said is up in the $15 range, but I kid you not, over at the Thousand Oaks Auto Mall at the Subaru dealer, they just became an authorized dealer for Motul, and they're selling the 75/90 synthetic for like $6.35qt.! I've loaded up! The oil is great, and I don't think they realized their prices compaired to other suppliers. So if anyone is in the area in Southern California, I would highly recommend spending the money... it's a great deal! And to anyone else trying new products in their transmissions... don't use Mobil gear oil. Mobil 1 is GREAT for you motor, but their gear oil is junk! As far as the GM stuff, keep posting, I'm interested to hear how the longevity of that product is!

-If anyone is really conserned about there choice of oils... visit a thread of mine in maintenance, it is labeled "Factory vs. Synthetic OIL!" there is a bunch of useful information on there!
 
#14 ·
uh... no, I just bought four quarts at the time. I was just replacing my front axel seals in the transmission, and just happened to ask if they had the 75/90 Motul synthetic as I saw the sign on the wall, the man there said they did... but they didn't have it in a gallon, so I said thats fine, four quarts would do the same... after that, before he ran to get them, I asked how much it was per quart, and he said like $6.35 or $6.55 or something in the mid $6 range... I have the reciept at home, I will check and repost... but it was cheep, and that was just this past Saturday! Maybe the guy didn't know what he was talking about and entered the price wrong, but I know that they can't manually enter prices in there computer system... what ever it says, thats the price. So maybe he rang me up to the wrong oil, or he gave me some discount like I was there from a sister shop... but as of Saturday, the price was just over $6 a qt. Check it out, repost!
 
#15 ·
Alright, I just got off the phone with ROD over in parts at the T.O. Subaru... He just said that they were out of quarts but they have the gallons. He just quoted me the price of $29 per gallon, which comes out to $7.25 per quart. Maybe it is cheeper by the quart like how I originally got it, and not the full gallon jug... but still with it under $30 for a whole gallon, I am yet to find any place selling Motul that cheep! Thats half the price of what it is suppose to be! Tell me what you think, and keep posting! :D
 
#17 ·
I have four quarts of the syncromesh sitting in my garage ... I cant find a T70 torx anywhere... I also think that I want to mix it in with something else just dont know what yet... anyone have any suggestions?
 
#18 ·
So it sounds like 3qts of the old 75W90 Valvoline Dino and 1 Qt of Syncromesh will work fine otgether? Is there a specific name for it or is it just staright up 75W90 Syncromesh when I go the GM dealer?
 
#19 · (Edited)
IMHO, I personally don't like mixing fluids, but that's just me. They are all designed by different companies and in different ways. I prefer to go with just one individual fluid and if I don't like it, then I will drain it out and try another one.

And yes, just ask for GM Synchromesh transmission fluid - 4 quarts.
 
#20 ·
I just put the GM suff in my car, and all the hype it true. I can now find 1st gear at 20 mph with no grinding. I had Moble 1 synth in and it was no better, possibly worse than the stock stuff, so I put the car on ramps and drained 2.5 liters and replaced that with 2.5 liters of the GM suff, leaving about 1 liter of the Moble 1.
 
#22 ·
That synchromesh is not GL4 or GL5 rated. Neither does it have a weight specified on the bottle.

It's thin stuff.

Yes it helps with shifting, but the protection level is lower then what is recomended.

If you use all synhromesh, and are not mixing it with something thivker, I would change it much more often.

I used it in my DSM and it shifted smoother, but my tranny went bad that. It already had some issues before I switched to sychromesh, but I think this stuff is a little too thin/lower viscosity then what you should have in an AWD tranny.

I'm running Redline MT90 (75W90) in my 91 AWD DSM.

This is the 2nd tranny, like I said I was running straight sychromesh (actually BG Synchroshift, but they are all alike) in the tranny that went out on me.

I had about 25K miles on that gear oil. Maybe if I would have changed it every other oil change or something it woulda lasted longer. But that's a PITA, so I'm gonna stick with the thicker stuff.

Or mix it with something thicker, so you get the best of both worlds.
 
#23 ·
not to say you're not telling the truth but how Shynchromesh can be thinner than regular oil and at the same time help shynchros??? Synchros need friction, so logically if something increases their performance it has to be thicker to create more friction than regular oil. I put MT-90 which is already thick enough and added a quart of shynchromesh because i had this horrible grind in 1st every time i wanted to put it in with anything but slow push. Now the grind is gone and i can downshift when i'm rolling to a stop sign.
MT-90 is thicker than 75W90NS and it works better for synchros but is not optimal for tranny seals that need more viscosity.
 
#24 ·
Sounds as if you agree with me, as you mixed it with the MT 90, didn't go stright synchromesh.

From Redline's page on MT90 "MT-90 is a thicker 75W90 version of MTL.". So yes it is 75W90.
http://www.redlineoil.com/products_gearlubricants.asp?pvID=74&prodID=57&subcatID=18


Better shifting and better protection are 2 diffferent things. Thinner makes for better shifting, thicker is more protection. Life's full of trade offs.

I said that Snchromesh does not even have a weight on it, and does not provide adequate protection all by itself for an AWD transmission. Apparently you are in agreement, as you mixed it with MT 90.

If the Synchromesh is thick enough, why did you mix it with MT90? Cause it's not, it is thinner. It's the equivalant of 5W30 thickness wise. I'm trying to keep people from dumping in straight Synchromesh, unless they are willing to change the gear oil evert 10K miles.

It's not a post telling people it doesn't help synchros shift better. It has a special friction modifier in it that helpse synchros work better. But it is not GL4 or Gl5 rated, nor does it have a weight listed on it.

It's not a post aimed at you, I never said not to put a quart in with the MT90.

Would you put motor oil in your car that has no weight listed on it? NO! Then why put gear oil in that doesn't.

If you mix 1 quart in with some 75W90 gear oil, I think that's ok. I know the 75W90 does not shift as smoothly, but it protects the tranny better.

I'm on my second tranny, and like I said I used straight sychromesh in the first tranny, based on the advice from people on the DSM boards, etc.. I wish I never would have.

I'm trying to save people from having to replace a tranny prematurely. I don't know why you want to argue with me.

And frankly, doesn't look like you have done the reasearch I have either, I've done plenty.

Does Synchromesh meet the manufactures specs? NO

People considering using it: Mix one quart of Synchromesh with the rest 75W90.
 
#25 ·
dsmevo316g said:
Sounds as if you agree with me, as you mixed it with the MT 90, didn't go stright synchromesh.

From Redline's page on MT90 "MT-90 is a thicker 75W90 version of MTL.". So yes it is 75W90.
http://www.redlineoil.com/products_gearlubricants.asp?pvID=74&prodID=57&subcatID=18


Better shifting and better protection are 2 diffferent things. Thinner makes for better shifting, thicker is more protection. Life's full of trade offs.

I said that Snchromesh does not even have a weight on it, and does not provide adequate protection all by itself for an AWD transmission. Apparently you are in agreement, as you mixed it with MT 90.

If the Synchromesh is thick enough, why did you mix it with MT90? Cause it's not, it is thinner. It's the equivalant of 5W30 thickness wise. I'm trying to keep people from dumping in straight Synchromesh, unless they are willing to change the gear oil evert 10K miles.

It's not a post telling people it doesn't help synchros shift better. It has a special friction modifier in it that helpse synchros work better. But it is not GL4 or Gl5 rated, nor does it have a weight listed on it.

It's not a post aimed at you, I never said not to put a quart in with the MT90.

Would you put motor oil in your car that has no weight listed on it? NO! Then why put gear oil in that doesn't.

If you mix 1 quart in with some 75W90 gear oil, I think that's ok. I know the 75W90 does not shift as smoothly, but it protects the tranny better.

I'm on my second tranny, and like I said I used straight sychromesh in the first tranny, based on the advice from people on the DSM boards, etc.. I wish I never would have.

I'm trying to save people from having to replace a tranny prematurely. I don't know why you want to argue with me.

And frankly, doesn't look like you have done the reasearch I have either, I've done plenty.

Does Synchromesh meet the manufactures specs? NO, do you see them listed on the bottle? NO

"A post on the message board at www.oilanalysis.com found Synchromesh to consist of a 5W30 non-detergent oil with a friction modifer and an EP (extreme pressure) additive."
http://www.stealth316.com/2-pennzoil-synchromesh.htm

People considering using it: Mix one quart of Synchromesh with the rest 75W90.
 
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