Hi guys, great site. There is a lot of useful info here. I have kinda of a weird question or situation and I'll try to explain as best I can. I have a 97 Blazer 4x4 automatic tranny. Ok sometimes when I drive the truck will go through all four gears just like it's supposed too, and other times it will not shift into third gear unless I let off the throttle and let it coast just a little bit and give it gas and it will be in third and shift into fourth. It may do this 3-4 times then it will operate just fine. There is no real pattern to when it does it. Also it has a sound of liquid bubbling coming from the floor shifter. The tranny isn't hot, it will make that sound as soon as you start off, before the truck is up to operating temperature. It never slips or anything like that. Sorry for the long post but the more info the easier to diagnose.

 

The bubbling thing you got going on baffles me but other than that a few things come to mind about the way your trans is acting.
1 a failing or weak boost valve
2 a actuator piston sticking
3 dirt or debris in the valve body
4 Bad tps

Now a couple of questions when the last time fluid and filter was changed?
Does the fluid smell burnt and is it at proper level?
Sugestion if the fluid and filter hasnt been changed within the last 25K miles change it and replace the filter.
If problem persist have it checked by a professional.

 

I'll try and get the fluid and filter done tomorrow. I have no idea why it does what it does. The fluid sound reminds me of the sound a child makes when they are blowing bubbles in a cup of drink with a straw!

 

Seems that answer to your trans making a bubbling sound would be a bad seal or not fully seated transmission filter.
I would also check to make sure its not your cooling system bubbling.

 

It's not the cooling system, you can only hear it coming from where the shifter is in the floor. You can't even hear it from the outside. It has no leaks. ???

 

Well the site says to look for bubbly or foam in your trans for the gurgling noise and that a improper seated fliter or filter seal would cause the symtoms your having.Since you will be changing the fluid and filetr soon that should go away.Please post results after that step is completed

 

Ok I have an update. Yesterday I was driving and couldn't get the trans. to shift into third. So I pulled into the parts store and bought some Sea Foam Trans Tune and poured the whole can into the tranny. It started shifting immediately! I ran my errands and came back home, changed the fluid and filter-dirty dirty. I added half of another can during the fill up and it hasn't given me a single problem since.

 

Thats great glad your problem is solved for now.

 

So how does this Sea Foam Trans Tune Transmission Treatment actually work? Do you put a can in your auto transmission fluid, and run it for couple days, then drain it, then change transmission fluid...Or what exactly??

 

Thats what I would like to know also,I bought a can of it but havent used it in the trans yet.