Changing Transaxle Fluid

**Goldfever** · 08-22-2009, 09:57 AM

I have not visited this forum for a while and it appears some things have changed so I hope that I am posting this question in the correct area.

I have a 2000 Grand Am 2.4L Auto that is about to roll over 100K miles. I have never changed my transaxle fluid and according to the owners manual I am due for a transmission flush. I have spoken with a few people about this and there appears to be two different opinions.

Some people I am speaking with say that since the transmission oil has never been changed, there may be some sludge in there "holding it together." They say when I changed the fluid it may to more harm than good.

Obviously the other opinion is changing the fluid will help the transaxle last longer. So I am looking for some guidance here as well as what fluid to put in. Thanks in advance!

**AeroCleanse** · 08-22-2009, 11:05 AM

I would change it. I would use Amsoil Synthetic Low-Viscosity Automatic Transmission Fluid.

**Setec Astronomy** · 08-22-2009, 11:14 AM

Originally Posted by Goldfever

Some people I am speaking with say that since the transmission oil has never been changed, there may be some sludge in there "holding it together." They say when I changed the fluid it may to more harm than good.

That is transmission shop BS. I am 100% sure you heard that from a trans shop who wanted to sell you a rebuild, or from someone who was talked into a rebuild by a trans shop.

If your trans is malfunctioning, chances are slim that a fluid/filter change will fix it (but sometimes yes, particularly if you have a clogged filter and you have low pressure as long as the trans hasn`t been damaged by the low pressure yet), but if your trans runs fine, nothing but good can come from changing the fluid.

I`d use the Mobil 1 trans fluid, but I`m a Mobil 1 kinda guy. Really though, as long as you are changing it, it doesn`t matter much as long as you use a properly spec`d fluid.

**wfedwar** · 08-22-2009, 11:46 AM

agree, but....

Keep it clean. So many people hange their own ATF and end up causing problems by getting dirt inside the transmission. Since most automatics require you to remove the whole pan, it`s a lot easier to get dirt in there than changing engine or manual transmission oil. Just watch for that.

**Goldfever** · 08-22-2009, 12:05 PM

Thanks guys. The "gunk holding it together" sounded like bs to me as well. My transmission is currently running fine but I would like to keep it that way so I wanted to look into getting the fluid changed. Any suggestions on what type of shop to bring it to?

**Setec Astronomy** · 08-22-2009, 01:02 PM

Originally Posted by Goldfever

Any suggestions on what type of shop to bring it to?

Someone who doesn`t do transmission rebuilds, so they will have no incentive to BS you. Find a competent mechanic...local gas station, etc. Now I feel I have to regale you with transmission stories. For those of you that don`t like me, stop reading here.

#1 My friend buy an old cop car (`82 St. Regis, for Accumulator`s benefit), and the trans blows. He brings it to a trans shop that does a good job. I am working on my car, so I borrow my mother`s old wagon, while I have it, I decide to check the fluid, it`s pitch black. Since I`m already working on one car, and I need this one to get to work, I decide to go to this "reputable" trans shop that fixed my friend`s car and have him change the fluid. Mind you, the car has only about 50,000 miles on it, which was more than 50,000 miles is today, but still. So he puts it on the lift, drops the pan, and then tells me he can`t change the fluid. Why? Because this transmission is burned, it`s got varnish in it, if he changes the fluid the detergent in the new fluid will clean the varnish, and all my clearances will go to hell--I won`t even make it home, I need a rebuild. I tell him I can`t leave the car, I borrowed it as it is, I have to get to work, so I talk him into putting the old fluid back in, since he won`t put any new fluid in. He goes around the corner and comes back with a tin jug and pours the fluid in, and back into the car, after putting the pan back on, of course.

So all I can think about is what gunk was in his drain pan, and if he put a handful of sand in the tin jug while he was out of sight. So I went from a trans that worked fine, but had black fluid, to I don`t know what. From not wanting to have to crawl under the car and drop the pan, I now go to the supermarket and get some crappy recycled trans fluid. Then I go to the auto parts store and get a filter kit and some good trans fluid. I drop the pan, drain the fluid, wipe it out, put the pan back up, fill up with the crappy fluid. Drive around for a while, come back, drop the pan, put the new filter in, put the good fluid in...that trans went for the rest of the time my mother had the car and then she sold it to my brother...still fine the whole time he had it.

#2 I had a (GM but I`m too embarrassed to mention it) with a manual transaxle, that I bought when it was 3 years old, 37K miles or so, and the trans is leaking fluid out of the split case. I find a trans shop around the corner from work, ask them to fix it. They call me in, they have the trans out of the car, they want to show me the diff gears, which have teeth missing. The owner of the shop figures the guy before me ran it dry...so I have to pay tons to get the diff changed. The guy seems pretty honest, so I bring him my other car with the TH-350 to change the fluid, just as a maintenance thing. While it`s up on the lift with his guys working on it, the owner strolls over and looks up in the trans, then he comes over to me in the waiting room, and tells me the trans is "getting a little tired". So, it`s my second car, I don`t drive it much, so a few years later, the trans is not shifting right when it`s cold out and the car is cold. I don`t have much hope, but I decide to drop the pan to see what`s going on. So instead of the white celluose dense filter that GM uses, what do I see? A coarse screen, like on a Ford, and I`m *** is this doing in here? Once again to the store for a filter kit, put the right filter in, and after some miles to filter out the grit, the trans started working like it should again. Obviously the shop owner planned for me to come to him for a trans repair, that`s why he put an improper filter in (trans shop special--screen to fit a GM where there should be a paper filter?--or maybe it was a racing filter) and then planted the seed with me that my trans was tired to make me think he was a genius who could predict trans failures--what an a-hole.

Moral of the story? NEVER trust transmission shops.

PS GM started putting a magnet in the bottom of the trans pans about 20 years ago, make sure yours is still there (they are like those flat flexible refrig magnets, so they can come out) and if not make sure whoever services it puts one in.

**gofastman** · 08-22-2009, 01:51 PM

There is a shred of truth to what that shop said, however its not something you need to worry about that transmission with 100k on it. I beleve the service interval for severe duty service is 50k and it doesnt need to be changed at all if you fall under normal service, dont quote me on that though.

Some shops may try to sell you a flush for an additional charge but IMHO it isnt necessary on that tranny because simply droping the pan and replacing the filter removes 6.9 of the total 12.9 quarts which is more than suficiant.

The fluid you need is Dexron III, any kind will do for that application, synthetics are advantagous for towing or other extreme service, otherwise save your money.

The OEM trans pan gasket may be reuseabl, keep it if it is as it will work better than the ruberized cork one supplyed with most replacement filters.

Last, make sure you replace the oil filter seal, dont nick the surface it seals against (see image)

**Setec Astronomy** · 08-22-2009, 01:54 PM

Carn00bie., that looks like the dash...

**Setec Astronomy** · 08-22-2009, 01:56 PM

Man, I hope GM isn`t using that any more...that tapered seal interface is really not the best retention method.

**gofastman** · 08-22-2009, 02:10 PM

Originally Posted by Setec Astronomy

Man, I hope GM isn`t using that any more...that tapered seal interface is really not the best retention method.

Yea I`d like to see some sort of clip or screw there to hold it better, however I cant say I have ever seen a problem with them, have you?

**Setec Astronomy** · 08-22-2009, 02:31 PM

You know, back in the old days, the filters used to be bolted on with...shoot, I can`t remember how many bolts...might have been just one or two. But since I`m always under the car with a jack doing this, yes, I was off to the side and pulled one of those plastic ones at an angle I guess and broke the neck off in the valve body (or wherever that thing goes in). Perhaps it was just jammed and would have broken anyway, because I had a devil of a time getting it out--nothing to pull on.

Since that whole filter is encapsulated and it pretty much sits on the bottom of the pan anyway, I`m not sure why that seal needs to be tapered, why don`t they just do a radial seal and let the pan hold it in? Unless they are afraid the thing will fall out before you put the pan on.

I gotta believe they are using something else now, they started using that style over 20 years ago.

**Goldfever** · 08-22-2009, 02:43 PM

Originally Posted by carn00bie

There is a shred of truth to what that shop said, however its not something you need to worry about that transmission with 100k on it. I beleve the service interval for severe duty service is 50k and it doesnt need to be changed at all if you fall under normal service, dont quote me on that though.

Some shops may try to sell you a flush for an additional charge but IMHO it isnt necessary on that tranny because simply droping the pan and replacing the filter removes 6.9 of the total 12.9 quarts which is more than suficiant.

The fluid you need is Dexron III, any kind will do for that application, synthetics are advantagous for towing or other extreme service, otherwise save your money.

The OEM trans pan gasket may be reuseabl, keep it if it is as it will work better than the ruberized cork one supplyed with most replacement filters.

Last, make sure you replace the oil filter seal, dont nick the surface it seals against

You are right about the 50K but I don`t find I drive my car that hard and I drive mostly highway miles. I am thinking of taking it to a GM stealership because I have recently moved and do not know of any good mechanics in my area. This is not something I trust myself doing. I know they will charge me more but hopefully it will be done right by someone who is somewhat familiar with my transaxle.

**Setec Astronomy** · 08-22-2009, 03:24 PM

Originally Posted by Goldfever

I am thinking of taking it to a GM stealership because I have recently moved and do not know of any good mechanics in my area. This is not something I trust myself doing. I know they will charge me more but hopefully it will be done right by someone who is somewhat familiar with my transaxle.

They should do fine with it.