03 Yukon Denali trans issue
 

My second Issue is my trans on my truck with 175k I check the trans fluid it's a brownish red. Now matter what gear I'm in slow driving or fast before it shift in any gear there is a slight Rev in the gear before it changes the trans doesn't jerk or anything just that slight Rev before shifting into gear. Now the trans fluid never change I was wondering if I drain the fluid and change the trans filter will that help. Now my pervious post I said my exhaust manifold on the driver said has a small crack in it will that cause the trans to rev shift.

The exhaust manifold crack could cause driveability issues and could set an engine code, but I seriously doubt it has anything to do with your transmission woes. Try never servicing the transmission over 175k miles, you're lucky it's lasted that long. Sounds like the clutches are pretty much on their way out, at this point a fluid and filter change would probably only make things worse.

2004 Bonne SLE
1971 Chevelle SS

Kind of figured it was the clutches that rebuild gonna cost some money might be cheaper to get one from a crashed denali even then that's taking a chance o well thanks for ur input

Cracked exhaust manifold could cause an obd code to happen.....either "dilution" or catalyst related.....no biggie.

Obviously, you wold want to change the trans fluid to see if that will fix your shifting issue, but I doubt it will. Different clutch packs for different gears......if the shifting problem is happening in every gear, I doubt it is a clutch pack problem. I would think it has more to do with the line pressure supplied to the valve body......still pricey.....

I could drain fluid and see what happens and change exhaust manifold

With the fluid already brownish red, and it not being serviced ever as far as fluid/filter changes, you could run the risk of the transmission failing fast when you change the fluid/filter, because if the gears/plates are worn badly, then the metal bits in the transmission could be what is still giving it the friction it needs to keep shifting. If you change it check the fluid for excessive bits of metal, I'd drain the fluid into something plastic, like a big fluid catch pan, and then run a strong magnet like a rare earth magnet though there, and see if there are any metal shavings..

But as already mentioned, if the trans is already on the way out, a fluid change will most likely do more damage than good.

Then I will leave it alone and let it fail since I don't really no what's going on

As long as the fluid does not smell really burnt, then another option would be to collect the fluid, then when you remove the filter check the pans magnet, it should have the typical greasy goo on it, if you see big metal flakes then consider putting the old fluid back in after the filter change.
Also like I suggested use a rare earth magnet, and check over the fluid well with it, if you see no big metal flakes, then go ahead and put a new filter on, close it back up, and top it off with Dexron 6, you'll still have a bit of the old fluid in the system, so you won't be going with all new fluid...
Whatever you do just don't get a full flush, unless you have the money to rebuilt the transmission in case it cause it to fail.
Either way eventually failure is going to happen, I had slipping issues with my tranny, and a filter change, then topping it off actually helped considerably, it all depends on the state of the clutches.

I took my truck on the i95 highway and it seem to shift fine even in the city.Now that it's getting colder. Remember I have a leaky driver side exhaust manifold so I can't think that has to do with my truck drivability hot air vs cold will I would have to replace in order to rule out the problem. I brought the truck like that so my guess it got worst Maybe I'm rite or wrong never no a issue can be something so simple.

I notice since I foxed my coolant issue my rl truck seems to shift fine maybe air peressure was getting in the coolant system like I said before it could be the simplest thing that can cause a problem. Every issue ain't always the same for every truck thank you all for who gave me different possible issues.