2004 denali downshift question

[pnwdan]

Recently my Denali has been downshifting hard from 3-2 and 2-1 when coming to a coasting stop. I noticed that the RPM raises slightly upon downshifting as well. I've searched for this issue but haven't come up with much as far as answers. Any thoughts?

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[01ssreda4]

Checked your fluid level lately? Any check engine lights? Sound funny but a faulted MAF can cause max trans line pressure which causes harsh shifts. Just thinking aloud....

 

[pnwdan]

Checked your fluid level lately? Any check engine lights? Sound funny but a faulted MAF can cause max trans line pressure which causes harsh shifts. Just thinking aloud....

No codes and fluid level is fine but I am going to change it and the filter soon. I cleaned the TB but not the MAF. Ill look into that

 

[01ssreda4]

If its not any of that then it possibly something needing service inside the trans unfortunately.

 

[pnwdan]

If its not any of that then it possibly something needing service inside the trans unfortunately.

did a full fluid swap and filter change this weekend. the inside of the pan looked really good. cleaned the MAF as well. seems to have settled down a bit.

 

[pnwdan]

I'm bumping this because it is still occurring. The trans works great with the exception of a hard 3-2 downshift. 2-1 is louder but is only the typical clack from the slack in the drive shaft splines. i did have BB tune my truck and Justin stated that a dirty throttle body will cause the truck to keep the RPS higher when stopping thus harder downshifts. i have cleaned the TB and still no change..

 

[pnwdan]

I just wanted to update this.

After searching and searching, the best info I could come up with is that a solenoid or something is sticking causing the harsh downshift so on a whim I tried what others have for similar issues. I put a bottle of red Lubegard in there. I'm not usually one for just hoping for a miracle in a bottle but after having it in there for only a few hours it has already cut the feel of the harsh downshift in half. Time will tell and if anything changes I will update this again.

 

[DeepSeaFish]

Sounds like a bad solenoid on the valve body maybe. I had a similar issue recently which resulted in a burned solenoid. Other possibility could be a torque converter issue.