Impala 3.5L with Check Engine light and rough shifting

RShea said:

As a side note- if the transmission has to be dropped, then I will also have the small oil pan leak done at the same time, since the way I understand it the Trans covers part of the pan access and you either need to jack the engine or take the transmission out of the way??

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Both as I recall. But that was on the 3.4 altho I would expect it to be the same for the 3.5.

For oil pan work, you usually have to jack up the engine off the subframe a few inches on the passenger end, and separate but not remove the transmission from the engine block. The latter part is done by removing the torque converter bolts and loosening the bell housing bolts to allow a gap of ¼-⅜" between them.

That's all moot since they will be removing the transmission. And for that, they will be dropping the subframe, so doing the oil pan ought to be pretty easy at that point.

HTH.

Doug

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RShea said:

So the transmission pan was dropped today and the bad news was there were some metal shavings and debris in the pan. So looks like it is not just seleniods at all and needs more than that. So probably start looking for a newer 8th generation Impala...

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Meh...
You took it to a transmission shop and that's fine but them folks will freak over anything too, not to say there may not be serious issues... And I certainly would start saving money just in case but I've driven cars with transmissions that every year I did the trans fluid & filter change (DIY every 10k) there were shavings in the pan, you haven't had the trans fluid changed in 60k plus so that's really not a big surprise to me...

I keep up on the trans & filter changes, mostly because it's so darned expensive to fix but shavings, I've driven cars with shavings for 4-5 years before... No, it won't last forever but it may go on for some time yet. Personally I would drive it but keep up on the fluid and filter changes, assuming you had it fully flushed you can probably go 20k now... Depends what you want, I'd definitely start saving for the next car but you may still have some time.

178,000 miles is a long haul for the 4T65E. Clunking and sliding into gear is a bad sign.
The TEP Basic V6 4T65E rebuild is just under $2,000 for a transmission that will run a lot more miles. https://www.tripleedgeperformance.com/New-Back_to_Basix.html

A film of glittery sludge in the pan isn't as much to worry about as you might think. 1/8" to 1/4" of gray sludge is not a good sign but a glittery film with a furry gray covered magnet is normal. These units have a multilink silent drive chain and it tends to shed a lot of fine iron particles. This iron is the stuff that makes trouble with the control solenoids and stresses the transmission.

I'd put a Magnefine filter in the trans cooler return line when you install the replacement transmission. Dave no doubt installs the upgraded pan magnets.

RShea said:

I did not take it to a transmission shop, but to my regular mechanic. Definitely a long list of issues that point to more than what you are saying- clucking and noise if you manually shift into and out of 2nd gear. The CEL 2 error codes I posted, gas mileage now about 3 or 4 mpg lower than I ever got on the vehicle. Slow pick up and starts when you press on the accelerator. Now the cruise control will not engage at all.

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mk...
Yeah I learned somewhere in my late teens to early twenties (after a good 3-4 rebuilds and replacements) not to EVER manually shift an automatic.
And some folks will tell you it's fine but then they're not the ones paying for the repairs, as I was told to put it in Drive and leave it there.
Only time an automatic needs to come out of drive is for it to go into Park and/or Reverse, and to come to a full stop before moving that lever.

Like I said it took several rebuilds before I learned, maybe in your case you can also get a used transmission put in, back in my days it used to cost $300-$700 between a used and a rebuild parts and labor...
I've heard prices have gone up but I think you can still get a used one put in for about a thousand, fortunately I took my lessons seriously at some point, haven't had to replace or rebuild one in a good long time.

You need to keep up on fluid and filter changes as well.
I was told that, too.
That one took a little longer to sink in than "don't shift it manually."
I believe I started changing fluid and filters in my 30's sometime, every 10,000 miles.