Has anyone changed the ATF in a CTS?

Z71 · #1 (**permalink**) 05-05-07, 08:55 AM

How much of a job is it? My GMC truck was easy to do as were my other GM cars, change the filter, fill the pan and start engine to pump out old while adding new. My local trans expert has never seen a CTS in his shop so I can't get his advice and I can't get a definitive answer from my Cadi service advisor on whats involved.

I want all of the ATF changed out to Amsoil synthetic ASAP, the engine and rear axle were done long ago.

I don't need any opinions of synthetics good or bad, I been putting synthetic in everything since 1975 so there is no point trying to convince me otherwise.

nothingbettah2do · #2 (**permalink**) 05-05-07, 02:33 PM

yes i have not done it myself but after reading on some of the stuff it seems easy. mine is a 5 speed manual so it takes less fluid than automatic which sucks cuz its best if u just flush everything out. im in the same boat as u are too. im a synthetic freak so i ordered 2 qt of amsoil 80w90 gear oil for my differential and fully synthetic amsoil for my transmision

nothingbettah2do · #3 (**permalink**) 05-05-07, 02:34 PM

i suggest you change your differential fluids too cuz the cts are sometimes known for differential going out on them. they are both the procedure

Z71 · #4 (**permalink**) 05-05-07, 06:09 PM

I already have Amsoil synthetic in the posi. OEM axle started making noise at 1800 miles and was replaced. First thing I did after getting the car back (dealer drove car back to me 100 miles to break in axle) was to drain out the stuff they put and install the Amsoil Synthetic. Just over 15,000 miles and not a noise from the axle.

Manual trans is easy but I have a 5L40E 5 sp auto trans. I don't see any dipstick.

B0000rt · #5 (**permalink**) 05-05-07, 06:14 PM

Does the DIC say to change it?

dkozloski · #6 (**permalink**) 05-05-07, 06:22 PM

The CTS has an automatic transmission that's assembled in a clean room and sealed at the factory. There is no dipstick because the engineers are convinced that a major share of transmission troubles come from dirt introduce by dinking with it. Unless you are driving across the Gobi desert, it might be wise to observe the transmission OLM.

suprane1 · #7 (**permalink**) 05-05-07, 10:12 PM

Quote:

Originally Posted by dkozloski

The CTS has an automatic transmission that's assembled in a clean room and sealed at the factory. There is no dipstick because the engineers are convinced that a major share of transmission troubles come from dirt introduce by dinking with it. Unless you are driving across the Gobi desert, it might be wise to observe the transmission OLM.

The transmission being built in a clean room has absolutely nothing to do to with the fact that the additive package in ATF wears out, just like it does in engine oil. To say putting fresh fluid in the transmission is akin to putting dirt in it is ridiculous. I just changed the fluid on a BMW, and BMW used to say that there ATF would last the life of the transmission. The fluid was completely black, and yes it will last the life of the transmission, except that life is a much shorter one than it could be. Do you really think GM cares if your transmission lives 100k+ miles. It is out of warranty, and how do the dealers make money, it has to fail. There is no dipstick to make it harder for you to work on so you will let the dealer take care of it when it fails.

Even BMW has now backed off the changing of ATF fluid. Why, because the majority of their transmissions fail just past 100k miles and its giving them a bad reputation. GM already has a bad reputation so why would they be different now.

dkozloski · #8 (**permalink**) 05-05-07, 10:50 PM

Quote:

Originally Posted by suprane1

The transmission being built in a clean room has absolutely nothing to do to with the fact that the additive package in ATF wears out, just like it does in engine oil. To say putting fresh fluid in the transmission is akin to putting dirt in it is ridiculous. I just changed the fluid on a BMW, and BMW used to say that there ATF would last the life of the transmission. The fluid was completely black, and yes it will last the life of the transmission, except that life is a much shorter one than it could be. Do you really think GM cares if your transmission lives 100k+ miles. It is out of warranty, and how do the dealers make money, it has to fail. There is no dipstick to make it harder for you to work on so you will let the dealer take care of it when it fails.

Even BMW has now backed off the changing of ATF fluid. Why, because the majority of their transmissions fail just past 100k miles and its giving them a bad reputation. GM already has a bad reputation so why would they be different now.

There you have it folks. More anecdotal evidence. GM's OLM systems were developed by a team of lubrication engineers led by a lady that is possibly the foremost lubrication engineer in the world, Dr. Shirley E. Schwartz.
Her projects are reknowned and praised by her peers in the field worldwide. Let's all discard her acheivements on the basis of some conjecture from the conspiracy theorists down at Cooter's garage.

suprane1 · #9 (**permalink**) 05-06-07, 01:17 AM

Quote:

Originally Posted by dkozloski

There you have it folks. More anecdotal evidence. GM's OLM systems were developed by a team of lubrication engineers led by a lady that is possibly the foremost lubrication engineer in the world, Dr. Shirley E. Schwartz.
Her projects are reknowned and praised by her peers in the field worldwide. Let's all discard her acheivements on the basis of some conjecture from the conspiracy theorists down at Cooter's garage.

Oh, well then, that proves it, obviously GM transmissions last forever because the foremost lubrication engineer is on the job. And Al Gore invented the internet that we all so love, So What.

GM transmissions still fail, and the fluid still goes bad, if you think black worn out fluid is good then keep drinking the Kool Aid, because eventually that poison will kill you. Signed Cooter

dkozloski · #10 (**permalink**) 05-06-07, 01:48 AM

What the transmission OLM team did was analyze the oil, additives, and condition of a multitude of transmissions to determine the complete mechanism of oil deterioration and additive depletion. They then determined what operating parameters would be the best predictors of oil condition. They then figured out how to monitor operating conditions and thus be able to predict when and how the oil would no longer give the required lubrication and protection. This is the same methodology as the engine OLM. Just like engines, heat is the biggest enemy of transmission lubricant so when the transmission is hot the percentage of life counts down quicker. Other operating parameters are monitored and each is given a weighted influence. Over the years the system has been fine tuned as more information is gathered. The data was fully examined and validated. GM transmission still wear out and oil goes bad but GM has a hell of a lot better handle on the mechanisms of failure than the guys down at Cooter's Garage.

z06bigbird · #11 (**permalink**) 05-06-07, 05:45 AM

Quote:

Originally Posted by dkozloski

There you have it folks. More anecdotal evidence. GM's OLM systems were developed by a team of lubrication engineers led by a lady that is possibly the foremost lubrication engineer in the world, Dr. Shirley E. Schwartz.
Her projects are reknowned and praised by her peers in the field worldwide. Let's all discard her acheivements on the basis of some conjecture from the conspiracy theorists down at Cooter's garage.

One would have a hard time identifying or discarding any of Dr. Schwartz's acheivements. Some might say that it would be significantly easier to disgard her achievements if that is really what you want to do.

Z71 · #12 (**permalink**) 05-06-07, 09:11 AM

IMO the synthetic ATF is far superior to the low bidder atf that Cadillac used to fill it new. The weak link in the chain is fluid. I say the OLM is great, but the low cost ATF the assembly plant used is another thing.

My CTS sits a lot as I don't drive it in the winter (have 04 GMC Z71), last year it sat from October to Late April of this year. Thats 6 months in unheated garage and perfect opportunity for the mineral ATF to degrade. Every vehicle I have ever owned since 1980 has been changed over to synthetic ATF, so I want the mineral ATF to come out. Besides, I sell the stuff and got to have in my vehicles.

I was hoping someone had this done or was aware of exactly whats involved so I would be a leg up on the dealer in getting them to do exactly what I want.

I have the SM's on order so I will have to wait to read up on the procedure.

B0000rt · #13 (**permalink**) 05-06-07, 11:04 AM

If you're so inclined to do so:

You obviously wont' get all of the fluid out if you're just dropping the pan....

Z71 · #14 (**permalink**) 05-06-07, 11:45 AM

Thank You, very helpful. Never would have known the drain/fill bolts must be replaced.

If my other capacity info is correct, the total fill is 9qt and by dropping the pan it will replace approx. 6-6.5 qts. If I change it several times over the next couple months I should get to about a 90% or better purity. Maybe know I know whats involved I am better able to talk with the service people and pretend I know what I am talking about.

Its even possible with only 16,500 miles I would not have to remove the pan? Have to ponder that.

dkozloski · #15 (**permalink**) 05-06-07, 01:22 PM

Cool temperatures are the ideal conditions for long term storage of oil. Heat is what does the damage. The OLM system was validated using dino oil so the use of synthetic has the potential of providing a margin of safety. Follow the procedures in the FSM to get the most complete change.