johnb5345

I've done a lot of searching and haven't been able to find the procedure on how to change the tranny fluid in my 2007 Cobalt. It has the 2.2L motor and the 4-speed auto tranny. I would like to drop the pan and change the filter but since there's no dipstick, what am I supposed to do with those plugs on the side of the tranny? The car has 107,000 miles so I figure it's about time to get new tranny fluid in there.

nhanson

iTrader: (1)

Drop pan, replace filter and gasket, install pan, fill with Dexron 6 at the top of the trans (fill cap), theres a check plug somewhere (on the side i believe) it will leak out once its full

Sharkey

iTrader: (1)

drop the pan, change the filter, re-use the gasket (its a re-usable gasket, dont replace it with cork or neoprene, it will leak) and re-install the pan. fill the tranny up through the black plug on the top, put 6L of dexron VI in. start the car, put it in forward and reverse for 3 seconds, return to park. with the engine still running get under it and on the passenger side of the tranny case near the passenger side axle there is a 7/16" plug. remove the plug (have something to catch oil with) and let the oil drain out till its just dripping. if no oil drains out add fluid till it does. . re-install the plug before shutting the car off, and dont forget to put the fill cap back in the top of the tranny.

checking the level needs to be done with the car on 4 jackstands. its important the car is level or you wont get the fluid level set correctly.

johnb5345

Should the car be warmed up before I drop the pan? Do you mean 6 quarts of dexron VI? And will I have to take off the passenger side wheel to get to that plug? Is there only one plug and is it a hex-bit plug?

Sharkey

iTrader: (1)

its actually better if you let the car sit overnight, this allows more oil to drain out of the torque converter back into the pan, and you will actually change more of the oil. and no you will not need to remove the tire, its just above the pan rail near where the passenger side axle goes into the tranny.

up here in canada we have literadex6, much like literacola. i guess if all you can get is quarts it will work.

johnb5345

So, there's only one plug then? My local dealership told me that there's 2 plugs I have to take out on the side of the tranny. Is this true? I haven't looked at it yet, but I will tomorrow.

Sharkey

iTrader: (1)

no there is only one plug. i found a pic, lemme see if it works

johnb5345

Thanks a lot for the pic and all your help. I got the tranny fluid and filter changed today and it went pretty well. One thing I had trouble with was removing the old filter seal in the transmission. Since it was pressed in there, I used a pick tool and hammer to bend the edge of the seal in until it finally came out. I guess I really didn't need to change that seal, but I figured since I had a new one, I'd do it. And I reused the original pan gasket as you recommended. When I tightened the bolts up, I tightened them until they stopped which I'm assuming is okay? I think the bolts came to a stop because of the metal frame in the gasket?

And when I put the new fluid in, it took the full 7 quarts and I was about to go buy more but the plug hole started leaking just after I put the entire 7 quarts in.

Also, before I took the plug out, I shifted through all the gears and then put it back in park. Does this matter or should I have only ran it through reverse and drive?

Sharkey

iTrader: (1)

shifting through all the gears is fine, generally i just go reverse and drive. you didnt need to change the filter seal, usually you can do more harm by changing it. as long as the filter went in tight itll be just fine.

johnb5345

I forgot to mention when I had the pan off, I noticed the old filter was rubbing on the pan since there was some shiny spots on the pan. Are the filters suppose to touch the pan?

Sharkey

iTrader: (1)

yes, the filter is held in place by the pan.

johnb5345

So the filter is suppose to touch the pan? When you hit bumps driving, wouldn't that cause the plastic filter to crack and break apart?

nhanson

iTrader: (1)

pan is bolted to the trans so it should be minimal movement

johnb5345

Okay, I looked at the old filter and it's got two round contact points on the pan side so I'm assuming that's what touches the pan.

Sharkey

iTrader: (1)

thats what those are for. most late model transmissions have filters that slide into the filter pickup and are not bolted on, they rely on the pan to keep them from falling out of the pickup.

Phil424

You don't have to mess with that check plug. The car takes 6.9 Quarts of Dex 6 with a pan drop.

Sharkey

iTrader: (1)

no it doesnt. every car is different, it can all depend on how long you took doing the service. when the pan is off the torque converter will slowly drain back, if you have the pan off for 30 seconds you will have more fluid still in the tranny that if you have it off for half an hour.

always check your fluid level. would you change your engine oil and put back exactly how much the book calls for without checking the level? no you wouldnt. low fluid in a tranny can cause slipping, high fluid can cause the fluid to aerate, causing lube problems. fluid level is important, make sure its correct

nhanson

iTrader: (1)

pretty much this

johnb5345

Yeah, I had the pan off for about an hour because I was trying to get that old filter seal out. When I filled the tranny back up, it took exactly 7 quarts before fluid started dribbling out of the check plug hole. I wish these cars had dipsticks for the tranny. A poor design in my opinion. And one more reason for the vehicle owner to pay $200 at a dealership to get it changed. Are all GM cars and trucks made without tranny dipsticks now?

nhanson

iTrader: (1)

No.

Sharkey

iTrader: (1)

the no dipstick thing is nothing new, gm started it in the early 90s with the 4l30e transmission (not actually used in a gm car/truck, used by isuzu and bmw), and first came into gm stuff in the 4t40e in the 95 cavalier. gm is slowly switching over to this but they arent all there yet. most auto makers are going to the no dipstick thing now.

the thought behind it is transmission fluid doesnt just evaporate, so unless you have a leak its not low. the fluid now is designed to last 100k miles and color is no longer a way to estimate the fluids condition. so in the auto makers eyes, they can save money by taking the dipstick and tube out and putting in a plug. 95% of people dont check the fluid level anyways, and those that do usually do it wrong (tranny not at operating temp, engine not running, in the wrong gear, etc) so why bother having it there anyways.

just be glad gm gave you a nice cap on top, most arent that nice. fords with this setup need to be filled through the level check hole in the pan, same with vw. others have a plug that can easily be mistaken for the band anchor pin, and when removed the transmission needs to come out to repair the damage. this is why i say if your not comfortable doing it yourself take it to a transmission shop and let the trained pros do it. lube shops pretend they know what they are doing, but the amount of work MR lube, pennzoil and lubeworld send to my shop, just to fix their screw ups, its amazing they are still in buisness.

Phil424

Not true at all. The only way your going to get fluid to drain out of the converter is if the converter actually turns. If the front wheels of the car are not moved, nothing is going to drain out. And to add to your oil comment, if you drain the oil completely and you know the exact capacity the engine takes why would you check? Is an extra quart going to be trapped somewhere? You don't know what your talking about.

Sharkey

iTrader: (1)

i dont know what im talking about? the certificates hanging on the wall at my shop beg to differ. im an ATRA certified transmission rebuilder and diagnostician.

in almost all automatic transmission fluid is picked up by the filter, it goes through the pump and then charges the torque converter. when you shut the motor off the torque converter is completely full, and the way everything is designed it wont drain back under normal conditions. however if you now remove the pan and filter fluid is able to drain backwards from the converter, through the pump and back out the pickup hole. generally, not much will come out, however the converter can drain till its just under halfway full, basicly to the bottom of the hub. your converter doesnt have to be turning for oil to come out of it.

and if you dont check your engine oil after changing it your an idiot. the dry fill spec and what itll take on an oil change are not the same. oil gets trapped in the oil passages and the oil cooler, and specs arent always 100% correct, thats why engines have dipsticks. transmissions are the same, the 4t45e takes around 11L of oil on a complete fill, but you never get all the oil out of it on a service. oil will slowly drain out of the converter, and like i said, only half way. oil is also in the valve body and the side cover, cooler, and in all the oil circuits, and that doesnt get drained. a rough number for a service may be 6.9l for the 4t45e, but its not an exact, thats why you check it

if you didnt have to check the oil level they wouldnt even put a level check plug on the case.

johnb5345

Another question: Does the transmission have a sensor that detects if the fluid level is too low or too high? Like will the check engine light turn on if the level is incorrect?

Sharkey

iTrader: (1)

no there is no fluid level sensor in the 4t45e, or any production transmission i know of. basicly the theory is you take it to a trained professional for service/repair and they set your level correct, and if you dont notice any puddles where you part it must be ok. however if the level is too low you will start to notice the transmission "neutralizing" or "falling out of gear" when on hard corners, with the level lower it may start shifting incosistently, and will likely pick up a gear ratio error code before much time goes by. however that can take several quarts of oil low to cause things like that.