I'm interested in this. Can you explain what you have heard? Is it a "regular" gasket or is it the rubber "cord" type that fits into a groove in machined metal? Anything?

Maybe Sleeper can help with this. I believe he has the Service manual.

 

Ugh, this is one thing I've really been thinking about. My HHR is a few hundred miles away from 50k, but it is also going to be 5 years old. Seems like 5 years is a big time to do some maintenance work. I've been debating about getting the transmission flushed, but I don't know if I should. I'm planning on keeping this car for many years, so I want it to stay in good shape. I don't know if draining and refilling is sufficient, or if I need it flushed, but I take it the dealer has to do it either way?

I'm also wondering about a coolant flush/refill, or drain/refill, but that's another story I guess...

 

https://www.chevyhhr.net/forums/show...mission+gasket

Link to thread on this BB

 

I just had both the trans and cooling systems flushed for the first time about a month ago. At that time there was 125,000 miles on my '06.

The radiator and fluid was replaced 2 years (51,000) miles ago after a deer with a death wish forgot to look both ways, but the whole cooling system was not drained and the trans had never been drained or serviced until the 125,000 mile mark.

I pull a small trailer occasionally and the end of this month will be leaving on a 5 - 6K mile road trip pulling the trailer so based on the recommendations in the owners manual I had the trans and cooling system serviced by a GMC dealer. The Tech doing the work told me the 4T45 trans does not have the "normal" filter that we are used to seeing after dropping a trans pan.

There are a series of screens that get cleaned by back flushing and then new fluid is pumped in completely replacing all the old fluid and cleaner. Just dropping the pan would only allow less than half of the fluid to drain out and do nothing to clean the screens.

Don't know if that information is correct, but hopefully someone with experience who has done it will jump in.

Since the service I've put about 2,500 miles on it everything works just fine. No leaks, no drips everything underneath is dry as a desert.

 

Thanks, I missed that thread

 

I would do just the transmission fluid change with filter, no flush. Antifreeze, if you do it yourself, depends on what the old looks like when you drain it. If real dirty, flush it. If it is relatively clean, just refill with 50/50 Dexcool. As you already know, they say 5 years on the antifreeze change. I know GM recommends adding their cooling system seal tablets to the system when replacing antifreeze, part #12378254.

 

That's kind of what I was thinking... I can't change the tranny fluid myself though, correct? It has to be done at the dealer? The antifreeze I can easily do at home.

 

The transmission fluid change seems to be more involved due to not having a dip stick tube most of us are used to. I guess the dealer has a special tool/nozzle that allows filling properly. I am looking into what they use.

Yeah, I would think you could handle changing the Dexcool yourself. As you already know, be sure to bleed the system as previously stated in prior threads.

 

Curious on this, also........

Someone, Prestone I believe, made a back flush kit that tapped into a heater hose ( I used it a couple times many years ago....so, this is by fading memory). The heater hose was cut, a plastic "T" was clamped in and a garden hose was attached to the tee to back flush the engine. Afterward, you refilled with the proper mixture and tightened a cap, that was supplied onto the tee. i remember a complete set of instructions contained in the kit.

Wonder if these are still available and if they would work on our engines??

Afterthought......when I last utilized one of these, I attached the incoming water to a booster pump (I had then) to increase the water pressure from about 60PSI to a litle over double that.

 

I agree that changing the Dexcool every 5 yrs is a good idea. Engine coolant made with ethylene glycol has very stressful heat cycles and can become depleted. It is also vented to the open air. As it breaks down it could clog the heater core and affect the defroster.
Dexron 6 in the transmission is a hydraulic oil that is not intended to be changed or added to unless a serious leak occurs.
When the 4T45E was built in the Windsor factory, we weighed the dry transmissions before they were tested, and then again on the "button-up" after the test.
When the bottom oil pan was put on, it was leak tested with air, then it was oil filled. The variation was not too much, but if it sat overnight (or over the weekend), it could vary as much as 6 to 10 fl.ozs.
The transmission has no "groove" in the pan rail. The compression gasket was bolted down by an Ingersoll-Rand computerized "tap-tite triangular self-tapping" bolt system. If my memory serves me, it was somewhere around 30 inch pounds on a new gasket.
In the test repair bay, we removed the oil pans...the test stands measured the oil intake, cooler line flow and Valve Body oil pump pressures during the test. The button-up installed the pan after the final re-test, did the air leak test, the axle grease station, re-weigh and re-fill.
Bottom line is this...the torque convertor holds about 60 percent of the Dexron 6. The fill station usually added about 2.5 liters or so. The whole system is about 4.5 liters.
In my opinion, changing the oil is not worth the hassle.
If the tranny acts up, get it rebuilt or replaced.