V6 MANUAL FLUID ?????

[carls2010]

I here ya there, on the gear oil changes.- The trans guys i talked to have been doing rear ends and trans for over 30 yars, and the one i always use for most ifo is great.- He has actuall done alot of gm manuall trans and when i told him my issue he jumped right in and said transaxle fluid that is 80 weight [cold] - looks like trans fluid but is for manule.--He also stated stay away from syncro mesh fluids in gm as they stink.- And said the redline MTL IS GREAT I PUT IN.--p.s. just so you know , he said if gm does come out with fix on syncro, he bets they then will call for the transaxle fluid OR POSSABLE 10w-30 eng oil.--YES, SOME manule trans had to go from gear oil down too motor oil because of shift problem - He already had to use both types in some other type's of gm trans he does, when he updates them with correct parts,-cause orig gear oil is just to heavy.----- Would you no by any chance as im still gonna experiment with fluids, but most of the 75w-90 AFTERMARKET Fluids that everyone is trying in he AY6, HAVE limited slip already in thier fluid ? [alot of people dont know this] and im trying to find out if gm used it in thier orig part # that our veh calls for. - Wish i could find out as im researching.--- BUT gm does need to fix out syncro problem --------Was going to try lucas but expensive,Amd didnt see where anyone has tried it.[has the additive in it already, just like moble, amalie, royal purple, [stay away from] -YES IM STILL GONNA BOUNCE BACK AND FORTH ON THE FLUID TYPS. ------------ I love the guys that jump in and say AY6 TRANS JUNK,, Thier mostly the v8 guys.-I think its because thier afraid us v6 guys might have a better trans

[Shu71]

Carls2010, IIRC the Cadillac CTS 6 speed manual up to 2008 used a different 6 speed gearbox MV1. For 2008 and up they went with the AY6 like ours and even redline recommends their 75W90 NS GL-5 Gear Oil. They do mention this gear oil is

Designed for transmissions and transaxles - helps to slow synchros for easier shifting across a broad temperature range

I don't disagree with your findings in any way and may very well try the MTL GL-4 gear oil, I wanted to point out that the Cadillac changed their recommendationw hen they changed the transmission.

[carls2010]

yea but they orig called for a gl4 aproved fluid with it not gl5, but i guess it doent matter either way.--we just need new sycro's.--ive email the NHTSA, AND GONNA CALL GM HERE SOON.--And im contacting local tv news channels, you never know they may investagate and broadcast something for us.-they would love a good car company cover up ? or ignoring us problem.---give it a try, and contact gm, and the NHTSA,, OR WE WILL NEVER GET OUR VEH FIXED UNDER WARR.

[Shu71]

Carl, I couldn't agree more and recommended everyone to file a complaint with the NHSTA in another thread a few days ago. This absolutely is a safety issue and GM should address it accordingly. Does anyone frequent a CTS site and knwo if they are having the same issue? Granted I don't think as many CTS drivers push theirs as hard as Camaro owners but it would be interesting to know if they have the same complaint. I am not opposed the GL4 however the last thing I'd want is for GM to deny a warranty claim based on that fluid. When you say the used to recommend it in the CTS do you know what year and when they changed to GL5 and if any owners manuals state GL4?

[carls2010]

I goofed, sorry.--the cadilac with the AY6 did call for GL5 FLUID, AND IT SAID ALSO SOME SYN UNDER HARD CONDITIONS

[Shu71]

no worries carl. I am curious though how your transmission feels with the GL4 and what level of protection you are getting. Obviously the issue is mechanical (either a clutch issue, wrong type of synchro's, etc). My question is why only the 1 - 2 shift? If it were either of those things, it would rear it's ugly head on all shifts not just 1 - 2. I'm thinking it is either poorly machined parts or a case defect causing binding or the jump from 1st ratio to 2nd ratio is too much??? I recall the old trans that had a granny low first gear were difficult to grab second quickly and without binding as well. Maybe GM is aware of the issue but does not have a fix (other than giving us all a different transmission)???

[carls2010]

At this time, im running red line MTL That looks like automatic fluid, but is a 80 weight as when cold,, but its comes out as thin like automatic fluid, BUT IS for manule transaxles.---Funny i just did a 80 mile run for work and did some high gear shifting at about 4,500 rpm and good shifting.-- There was a guy on face book who told me to try, as he is running it and is at about 8,000 miles on it now.----- trans guy said it can cause just the 1 to second gear problem with tho;s brass syncro.--there has been a few veh that had clutch issues to,, like mine just a few times has reliesed high and jerk veh bad .. BUT most issues is with tho brass syncro's

[Ventmaster]

I've had limited time to research (23rd wedding anniv.), but have found a few things:
GL-4 has 4.0% EP additives (extreme pressure) and is for variable (light to heavy) use. Basic lube for synched and unsynched manual trans.

GL-5 has 6.5% EP and is rated for severe use. Synchronized trans only.

Ep additives can be corrosive to "yellow" metals like brass or copper.
These additives reduce friction by holding the gear faces apart with a thin film.
Synchronizers require a little friction in order to be up to speed and do their job. They are commonly made of brass (a soft metal) to avoid clash but will wear more quickly as a result. (Coming Honey!)

Cadillac has dropped the manual trans option for the CTS 3.6 for 2012 due to low sales.

Amsoil MTG is a GL-4 75-90w that's getting the most thumb's up for helping with shifting difficulty on the "oil" sites I checked.

[carls2010]

sweet info ,Vent.- very interesting ?? So far my best results have been the redline MTL., BUT MY VEH isnt as bad as some.- im going to try some 75w90 oil here where i work. [chrysler] and see how it act's. -- it does not have any l,slip additive in it and is GL5 RATED, CURIOS HOW IT WILL BE COMPAREWD TO OTHER SYN,, I USED THAT HAD LS ADDITIVE IN IT, DANG CAPS ON AGAIN, SORRY. lol

[carls2010]

yes , after many grar oil's and a trasaxle fluid i tied in the AY6, - And ifo i found and a few here here is my opinion on the only thing we can do for now 75w-90 synth, and or 75w-90 GL4 RATED FLUID.--After using the transaxle fluid like redline MTX, IT works great, BUT!!!!!!!! Will add alot of the clunking sound to our already clunking trans. [not talking about the gear clash] - So i have a 75w-90 back in.- So untill gm fixes our issue of the gear clash, and/or no second gear.[syncro's] All we can do for now.---- P.S. If anyone runs a gl4 75w90 weight for now and worry about warr issue, well when or if trans goes they will never know the diff when they drain it, and GL4 FLUID IS BETTER FOR THE SYNCROS anyways. - ---------- WAS AND very curios if anyone has posted or said if the 2012 v6 has same issue ???,mmmmmmmmm.---IF NOT ,GM, could of sqeezed in the fix with out saying anything, so as to not having to fix all the 2010-2011 vehs.------ Soooo has anyone heard or posted our issue ,,with a 2012 v6 asian tran ???

[Ventmaster]

I've ordered some Amsoil MTG75-90w to try. Yes its a GL-4, but I'm betting (hoping) GM went with the GL-5 trying to squeeze every MPG they can out of the car by going with the best lubricating -but not besting shifting-gear oil.

I'll let you know if my trans shears itself into bits, but I'm betting the GL-5 is overkill in this tranny.

[carls2010]

are you sure its still a 75w-90, as alot of GL4 FLUID WAS 75w80. but not all.----BUT The GL4 will be fine...--- I think the orig GL5 GM fluid was just gl5 ?? which just has a higher load capacity. [think thats the word i wanted to use]

[Ventmaster]

Yes, the AMSOIL MTG is a synthetic manual transmission & transaxle gear lube with SAE 75w-90 and API GL-4.

I know I'm playing a bit of Russian roulette, but I think our synchro's are getting blocked out by all the EP additives in the GL-5.

I put it in last night, replacing the Motul 300 (GL-5) I tried after the stock gear oil.
There is a noticeable decrease in engaging and disengaging the gears. Don't get me wrong-this will never be a "snick-snick" kind of gearbox, its still clunky, but less noisy because there seems to be a little less effort to engage the gears.
I've not had the grinding problem like some others, but I did have several "refusals" on high RPM 1-2 shifts. Really frustrating!

I only had a chance for a couple of tries, but both were 6500rpm 1-2 shifts that churned the back tires several times-despite not having a chance to turn the traction control off. Both banged right into gear without a wimper, a whine, or a grind.

[carls2010]

that fluid will do no more harm than what gm put in.--and if it goes to a warr issue they will never know the diff.- If the amsoil looks like other gear oil.---- Sounds like your trans is same as mine ,as not to bad.-yet, and not real bad like some others..- im currently have a chrysler,, 75w90 syn in mine that doesnt have the limited slip additive in it.--- Cant figure out if trans would be better off with the additive or without. ???????