Good write up!! How did the transmission feel after the oil change?

 

Thanks!

It's smoother going into gear. Also, quick gear changes are much smoother. I did a 6-4 downshift today at 45 mph, and it went smooth as butter. I was surprised, as it usually fights a little bit to go into gear. Overall, I'm glad I changed the gear oil.

 

Awesome How-To! Plan on switching over to the Red line 70w-80 and was wondering if this change voids the warranty?

 

This could present warranty issues if the transmission fails and they determine it's the fluid's fault. I'm going on faith that the fluid I used that meets GL-4 compatibility and 70w-80 viscosity range won't cause any issues. Seeing how the transmission is operating more smoothly and consistently, I do not foresee any issues that would need warranty coverage.

The question for me is use the poor-shifting OEM fluid and use the warranty, or use a better-shifting aftermarket fluid and avoid any issues?

 

How many miles did you have on your transmission when you changed this fluid? I ask because I'm at 5900 now and shifting is quite smooth. Of course, there's always the possibility that it will degrade over time if my fluid becomes as unsuitable as yours was, but I'm just trying to get an idea.

 

My car had just over 19k miles on it when the fluid was changed out. The MTF might last longer in a city environment since there's less pumping of it going around. I'm doing lots of hilly highway driving, so the transmission fluid gets pumped around a lot, and is subjected to decent torque loads in the higher gears.

 

Good to know. I'll probably end up doing this toward the end of summer. It has been shifting beautifully for now.

 

One note I'll mention is that with the T56 transmissions, the amount of fluid recommended in the US is different than in Europe/Australia. Less here than there. Many people filled it to the level of the Aussies because it helped with transmission noise and worked smoother. So maybe check that the same isn't the case here.

 

Mine from day one has not shifted smoothly and im at 12k now. Occasionally I will shift and it will be completely smooth and i wish every shift could be like that.

 

The biggest difference I've noted is that the transmission is consistent now. It's a bit smoother, and much more predictable. After it warms up a touch, it shifts the same every shift the rest of the drive. It doesn't matter if I'm shifting slowly or quickly.

 

good write up

did all this last fall with the clutch swap, I personally only use the level plug since its the tattle tail indicator to let you know EXACTLY when your under or over full. I couldn't find a reason to use the top plug since filling through the level was just as easy to me. /shrug

Like Sciphi said, this isn't much harder than changing your oil. Just MAKE SURE you use a GL-4 MT fluid. Which you won't find on most auto parts house shelves, so don't expect to run down and get some after youve already drained it... it won't happen. Your most likely gonna have to order it and have it on hand.

The only other thing I seen in doing mine is that the drain plug does not have a stop when your putting it back in, so don't put it in any farther than it was when you took it out. DIRECTLY On the other side of the threads is the differential and you don't want the back of your plug up against the gear because you put it in to far. Just be very mindful of this, shine a light in the drain hole so you get an idea what i'm talking about. No room for a mistake here.

 

Sciphi and Travis, can either of you provide a link for some good fluid to order? Cost probably won't be an object here since we only need 2 quarts of the stuff.

 

I'm really liking the Amsoil Synchromesh (MTF) in my transmission. Give this stuff a few shifts, and it's smooth sailing the rest of the time. Search Amsoil's Web site for it. It's about $15-16/quart shipped.

 

Mine has 22K and has shifted beautifully since new, but I think I'll switch to synthetic the next time I change the motor oil.

 

Folks have noticed these transmissions being all over the place with shift quality. Some shift really nicely, others shift poorly. Others, like mine, shift somewhere in the middle.

I'm still glad I got the OEM fluid out. Whether it had break-in debris in it or was just not a good batch, shifting improved with the new fluid.

 

Nice write up Sciphi. The Castrol BOT 402 fluid is a full synthetic fluid, 75W-85.

 

I was trying to think of the different ones I wanted to try... /thinking.. (i've slept since then)

Joe Gibbs Driven - Qualifying Gear Oil this is the one i REALLY want to try out. I'm not recommending anything, i just really liked the data on the oil in comparison to the OEM stuff. The biggest difference with this oil is that it doesn't have all the extra chemicals that street fluids have for longevity. This stuff has extremely low parasitic drag but has a short life as well. Of course in our cars it would still be lots and lots of miles.. but no where nearly as many as the street oils.

Red Line Synthetic Oil - Gear Oil for Manual Transmissions - MT-85 75W85 GL-4 Gear Oil I think this is the closest version to the OEM fluids numbers of the redline oils.. you'd have to double check.. once again, i've slept since then.


AMSOIL - Synthetic Manual Transmission and Transaxle Gear Lube 75W-90 (MTG) the reason i went with this over AMSOIL - Synthetic Manual Synchromesh Transmission Fluid (MTF) was.. ummm.. i can't be for sure. I think it was because I plan on putting a LSD in the car which MTF isn't recommended and I think the kinematic viscosity or the viscosity index... or both were closer to the OEM stuff. Don't quote me on that, do your own research plz.

The Castrol BOT 402 fluid is a full synthetic fluid, 75W-85.

and there be the OEM.. thanks for pulling up the name OnlyTaurus, i had forgotten what it was and would have had to dig it up again. haha

 

GM makes an excellent manual transmission lube specified for the Corvette and it's GL4 but I don't know the other specs to be able to say it's suitable for the Cruze. The Tremec manual trans in the 2005 Corvette was factory filled with Dexron III but later they changed the specs and developed a new lubricant. It really worked well in my old Corvette, especially the cold weather shifting. Here's a link to the place I got it from.

21018899 - GM Manual Transmission Lubricant - 32 oz.

 

Anyone do this on a automatic transmission? Any idea how process would change?

 

It's an entirely different (and more expensive) procedure. Most people will do a complete pan drop to get to the filter as well.

 

Got my two quarts of Amsoil Synchromesh in the mail yesterday. I hope to have time today to change it this weekend. I'll report back on my impressions.

 

Did you order it from me?

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Xtreme, did you get around to changing the MT fluid?

 

No, didn't get a chance to.

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I've put about 2000 miles onto the new MT fluid, and have nothing but positive reports. The shifting is consistent and smooth. It even made 4th stop rattling most of the time. When 4th does rattle, it rattles much less. No grinding into 2nd on a hard shift, either. It's the best the gearbox has shifted since getting the car.

So, if you're complaining about notchiness, hard shifting into 2nd, or 4th gear rattling, try changing the MT fluid first. For the minimal cost and time spent, the reward of smooth, consistent shifting is worth it.

 

amsoil manual Transmission & Transaxle Gear Lube 75W-90 or amsoil synchromesh 5w30? Why does that say 5w30? Isn't like that motor oil thin?

 

Read these: SAE Grade: Gear Oil vs. Motor Oil - Bob Is The Oil Guy

Gear oil - Wikipedia, the free encyclopedia

In a nutshell, motor oil and gear oil have two different, not compatible weight systems. A 5w-30 motor oil is very roughly equivalent to a 75w-85 or 70w-80 gear oil.

5k miles on the Amsoil Synchromesh, and it shifts great. Amsoil put 5w-30 onto the Synchromesh since some transmissions specify motor oil as a gear lube. They wanted folks to know that they had a better transmission fluid that met the motor oil weight specification.

 

How often should tranny fluid be changed?


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Whenever shifting gets bad, or 50k miles, whichever comes first. Manual transmissions don't have as frequent a change schedule as automatics since they're generally easier on fluid than automatic transmissions.

My shifting was feeling clunky/bad by 18k miles, so the fluid got changed then. Much better shifting resulted.

 

Got this done today. Surprisingly, I drained about 1-3/4 quarts out of the transmission, and filled 2 quarts but no fluid leaked out of the fluid level hole. Might have been low from the factory? Could also have been that my car was at a very slight incline.

Either way, shifting is noticeably improved, and much more consistent. It wasn't terrible before, but there were times when I'd have to force it into gear more than normal, and even ended up grinding a few times trying to go into 2nd because I didn't push the shifter down hard enough, having not been used to it. This made it all better.

Many thanks again to sciphi for giving us all of this information.

One thing I did note, it appeared that the 3/8" hex key was a tad bit too small. It wasn't prohibitively small, but did make me wonder if those are actually supposed to be metric. I didn't bother to check.

 

One thing I did note, it appeared that the 3/8" hex key was a tad bit too small. It wasn't prohibitively small, but did make me wonder if those are actually supposed to be metric. I didn't bother to check.

5/16 Hex for the Fill port up top and for the Drain port I used a 10mm Hex + 10mm Wrench that fit really snug.

I had to jerry rig a funnel out of thin cardboard [Aunt Jemima Waffle Box Flattened and then Rolled into a long, thin Cone] and Tape to reach the fill port since my regular oil Change Funnel could not reach down in that tight transmission area.

I Also taped a Triple Folded sheet of Aluminum to the Sub Frame where the drain hole would shoot the fluid to keep it from making a huge mess. I curved the Aluminum into a Shield that caught Fluid and directed it nicely into my oil pan.

Overall it was as easy as changing the engine oil once I went out and bought the Hex keys. I filled 2.5 quarts according to Andrei's recommendation.

I noticed shifting was much smoother right away when I took a test drive right after the Fluid Change.

:go: Time and money well spent, I'd say.

 

Glad to hear the Amsoil Synchromesh worked for you too!

I've got about 11k miles on the Amsoil now, and still like it. It's still consistent.

 

Does changing the fluid get rid of the notorious 1-2 grind on a hard shift? I'm contemplating doing it....I wonder what the dealer (or shop) would charge to do it if I supplied the fluid? I've got just shy of 20k on my ECO and the 1-2 grind annoys the cr@p outta me.

 

It certainly will help.

I'm not sure if it'll get rid of it completely, as damage could have already occurred if one was very diligently re-creating the problem. Mine didn't have many issues with the 1-2 shift, mainly because I rarely shifted it at the high RPM's and engine loads necessary to cause the problem in the first place.

I'd guess a shop would charge 1 or 1.5 hours of labor on an Eco due to an un-modified engine shield being difficult to handle. It's a simple operation that can be done in a driveway with the wheels on the car, if one were so inclined.

 

Yeah I've thought about doing it myself, I just don't have the hex sockets and didn't feel like messing with the shield (mine is intact). Thankfully I don't get on it often, only done it a handful of times, it would just be a good feeling knowing that if needed to, i could shift quickly without the grind. If I do get on it i try to shift between 5-5500 to avoid the issue altogether.

 

It's really not difficult. Removal of the shield involves 6 screws and 8 trim retainers, all of which can be removed with a screwdriver and a pair of pliers.

The hex sockets are cheap; whole lot cheaper than paying someone else to do it.


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Harbor Freight hex sockets are $10 and a nylon interior trim tool set that will remove the fasteners without buggering them up is another $10. Still cheaper than paying a shop to do it.

 

Synchromesh is much closer to the 70w-80 GL-4 fluid that comes in the 2012 transmission than the 75w-90. Although, they spec 75w-90 GL-4 in this gearbox over in Europe where it's made. I went with the Synchromesh to match the OEM viscosity better, and for better cold-weather performance. If I were regularly tracking the Cruze, which I'm not and have no intention of doing, a 75w-90 would be better to deal with those conditions of sustained very high speeds, high temperatures, and very high loads on the gears. For those of us who are ordinary commuters, the thinner fluid is better since it reaches its operating viscosity faster, and pumps better at the lower temperatures our cars will see daily. Even 110-130*F is cold for an oil, as hot as it feels to us.

The Synchromesh is recommended to replace a number of GL-4 fluids, and is said to be compatible with brass/bronze, just like a GL-4. So it's Amsoil's sneaky way of admitting it's a GL-4 fluid, without outright saying it.