Torque Converter Question

[2500SWATBurb]

Alright guys

My truck has 67,000 miles on it. It's a 90 model 3/4 ton Suburban.
400 tranny.
About 1,000 miles ago it started shifting back down after it had shifted up. Just for a second. It would shift up like normal and just fro a second kick back down and then back into the right gear. Like it needed just a little more oomph to get the right gear.
Well now... It's not wanting to shift up nearly as easy as it used to. It sounds like there is a huge fan under the truck spinning like mad.
This truck has been maintained like no other. I've never driven it hard, but I got the truck with 60k on it.

What could this be? My guess is that the torque converter is about to go.
Damnit!!!!!! Just when I almost had enough to buy my tires and wheels.

How much is a TC gonna cost me? If that's the problem.

 

[2500SWATBurb]

Can I get a bump?

 

[diesel4me]

check a few things..

Be sure the fluid level is correct..not over full, or low..then make sure the vacuum modulator is getting vacuum,and no ATF is in it,indicating a ruptured diaphram..check the govenor gear,it could be ready to strip the teeth off the nylon gear,that determines when it upshifts..(once the gear strips completely only first gear will work,no upshifts!)--
--has the filter and fluid been changed recently??..if not,it would be a good idea..a clogged filter can cause a whining siren type noise,and affect shifts...and a peek at the inside bottom of the pan will tell a lot,if its full of metal filings ,it is likely on its way out..