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transmission fluid change

80K views 70 replies 41 participants last post by  LVG8GT 
#1 ·
I plan on dropping the pan to change the oil and the filter, but without a dip stick, I was wondering how to fill the transmission. I never looked at it yet, but didn't know if I need a special tool for this.
 
#2 ·
When I am ready to get this done I am having the dealer do this. The 6L80E is a sealed unit which means checking the fluid is not required. And even so I have not found the filler neck on mine if there is one...
 
#5 ·
I would DEF have the dealer do it, especially if you're in warranty range - they will flush the system and clean the filter and will use the correct GM fluid, its worth having them do it for peace of mind IMO
 
#10 ·
dealer wanted 250 for a tranny flush. my buddy has the auot tranny machine and.did it for 100
 
#11 ·
Did mine today. The filter that O'Riley specified was wrong. It was for a 6L80E, but not for the g8's shallow pan. I used solvent to rinse out my old filter and re-used it. I called the GM dealer, but they were not showing the part # in the computer that was stamped on the AC Delco filter I was holding in my hand. (24235900)

To re-fill, I just put a tip off of a gear oil bottle onto what ever quart I was using at the time, attached a rubber hose, and stuck it in the filler / dipstick hole on the right side of the tranny and squeezed the bottle. There is a easily removable / replaceable rubber plug blocking the hole. You know it's full when fluid comes out of the hole in the middle of the pan after getting the tranny up to temp. There is a picture on the bottom of the tranny pan that depicts how to determine if it is full.
 
#17 ·
There is a easily removable / replaceable rubber plug blocking the hole. You know it's full when fluid comes out of the hole in the middle of the pan after getting the tranny up to temp. There is a picture on the bottom of the tranny pan that depicts how to determine if it is full.
I think this is the fill plug SMSO966 is talking about (circled it in red)....
 

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#12 ·
How often do you really need to change trans/diff fluid?
 
#13 ·
The tranny is a seal unit... The best way is a flush... the unit flushes All the fluid from the filter and converter, valve body, etc. not just the couple quarts you get by dropping the pan....
 
#19 ·
you have not tried it, have you?

A flush does not change the filter. For the price of a dealer flush, you can get the camaro deep sump pan and filter (PACE), buy the 8 quarts of synthetic fluid, and still have enough for a six pack of beer.

"couple of quarts..." hmmm...
 
#14 ·
I did mine with almost 60,000 miles. A complete flush is better, but the fluid didn't look that bad and there was hardly any sludge on my magnet. I completely cleaned the pan, flushed my filter with solvent, and put 5 quarts of synthetic fluid back in.

Better than nothing and only cost $40.00. I will try to do a full flush at 100,000.
 
#15 ·
My buddy works at a Chevy dealer, had him do the flush at 56k miles.
I stood and watched, and the fluid coming out was pretty dirty compared to the bright red fluid going in. I think I paid $140 for the flush, good peace of mind knowing it has been done now and good for another 50k miles.
 
#20 ·
In other vehicles (non GM), I have always loosed the tranny pan bolts and then drain. Change out filter, clean off pan magnet, wipe out bottom of pan, measure what came out, and add that amount back in. I've done that every 30k on a few of my cars and trans are still running strong another 100k+ later.

I have yet to do the G8 and I'm sitting at 96k. I know I'm due so I probably use the same method. Never heard anything good about flushes- seems like it would just move all the contaminates around and filter out very little.
 
#21 · (Edited)
If you guys are doing this yourself, make sure the car is level when you fill it and check it. When doing this at home with a jack, that means 4 jack stands and using a level on the transmission to make sure you've got all 4 corners at about the same height.

Otherwise buy the aftermarket Lokar dipstick for around $100 and you can just use that to check and fill. You would simply drain the fluid, put the bolt back, put the car back on flat ground, and use the dipstick. The dipstick must also be used with the car flat, but the advantage is that you don't need the car to be jacked up flat. Much easier. I know you said you don't want one... that's up to you. You'd have to buy another set of jackstands otherwise if you don't already have 4, and again, can be a pain to get the car jacked up and leveled on all 4 corners.

On some cars I have disconnected one of the lines between the transmission and the radiator, and extended one end into an empty bucket and the other into a clean jug of ATF. Then I just turn the car on until either the fluid dumping into the bucket starts looking new, or if I am about to run out of the new stuff. I've always done this with a second person at the wheel ready to kill the engine if anything bad happens. Fortunately I haven't gotten the hoses backwards yet. But I've only done this a couple of times so far. Of course I'd still recommend dropping the transmission pan and changing the filter, though (and yes, upgrading to the Camaro pan and filter is also a possibility). There are multiple ways to do that. You could try a pan drop, not adding fluid, setting up for this method and then you'd have to check the level and top off if necessary afterwards. That would waste the least amount of new fluid. But it's a bit more risky than sacrificing some new fluid when you pan drop. But you'll have to check the level regardless. Make sure to buy some extra ATF and set at least a couple quarts aside for topping off if necessary. Don't use all your new ATF in this home "flush" only to find that you're several quarts low. When operating this way, the system is obviously not sealed so there is not a guarantee that the fluid level won't change. So be cautious. This method has been VERY easy for me, but I have not done it in a G8 or anything very similar to a G8.

It's also a good idea to check the ATF again 1-2 more times after you check it initially and do some driving. Especially if you unseal the lines. Dipstick would be extra useful. I really recommend it. It disgusts me that GM doesn't add one. It's not because the system is magically more reliable than older transmissions with dipsticks. It's solely a cost-saving measure (well, and possibly one of those moves they made to try and curb third-party/home repairs and get more people to pay for dealer service, but I can't prove that). There are no lifetime fluids in cars from the consumer's point of view. A "lifetime fluid" in OEM speak means 100k miles.

BTW, if it interests you at all, Amsoil makes compatible ATF for our cars.
 
#27 ·
Everything you need to know right here about 24250062
 
#28 ·
Its a dealer "have" to type of thing. There's a specific way to flush this unit, at least according to GM. I'm alittle over 60k, and its a 60k maintance item... I'm too still looking to get more information, as my buddy is a GM Tech. I'm waiting to get a stack of information about routine maintance things to do.
 
#29 ·
I had my fluid replaced at 74k miles when i did my converter, find a reputable trans shop (assuming you can't do this yourself), that know about the 6l80e trans, and ask them to check/change the fluid for you. It would be cheaper than what the stealer will charge you, unless the dealer has a coupon that would make the price attractive.

There are also more transmissions out there that would requiere the same filling/check procedure, so trans shops should know what do, i gave my trans shop the details about the temp just in case, but they knew the trans either way, so it was more for my own piece of mind to know they had the correct procedure at hand. Again, make sure they know the trans, you'll be surprise how many shops have no idea about the trans when you ask them specifically about it. Dealers would also have this info at hand straight from GM.

Some people reuse the filter, but you can get the filter, and the gasket for cheap online.
I just bought the Camaro pan, filter, gasket from Pace, since i was doing the verter, and the parts were very cheap (about $80 shipped to my door), , so i figure the stock trans gasket and filter should be cheaper than the Camaro pan with all the parts, although not sure about that.

My trans fluid was still decent looking at 74k miles, the guys at the shop saved the old fluid to show me, and they said it was in fairly good shape compared to other fluids from other car brands with about the same mileage. I wouldn't have had any issues letting my trans go all the way to the 100k miles mark from GM, so that was a good thing.
I'll use the same shop again the next time i need to replace my trans fluid, and i'll probably get at least a new gasket, assuming the filter can be reused at least once.
 
#31 ·
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