just recently i had my tranny fluid changed, a few weeks after driving down the road about 35-60 the tranny will downshift when it feels like it. and during deceleration it will just downshift all of the sudden and shift back up and down till i either stop or continue to accelerate. wtf is going on?

 

almost sounds like my problem

 

Have you checked the fluid level?

 

replace your governor pressure sensor and solenoid one probably got clogged with junk.
also while your in there adjust both front and rear bands and replace the tc lock-up solenoid.

mine was acting up a couple months ago, did not want to shift would hold the gears too long etc.

bought all the parts and trans fluid (atf+4 only) and filter,
went to my local shop and asked for a fluid filter change,
they told me $50, then i told them to install all the new parts since they would be in there.
Quoted me $100.

shifts like a dream now!

 

Ditto mine quit shifting the day after I bought it. I replaced and the solenoid and sensor and it fixed it.... I had never touched a tranny in my life until dropping the pan and following the instructions in the service manual and doing it myself.... that parts along with the 5 quarts of atf+4 fluid ,filter and gasket cost me just over 200 bucks and about 2hrs of my time...shifts much better since.
As you knew the 33" tires along with factory gearing is hard on your transmission....and it is going to have a harder time staying in OD because of the added strain. But you probably already know this if youve had it set up that way for a while.

 

dont have stock gears i have 4:56's but i just installed em recently. thanks for the helps guys

 

have a 1999 3500 w/cummings diesel. same problem, trans keeps changing gears , does not know what gear it wants to stay in. A diesel mechanic told me to pull the main computer off the firewall and grind down all contacts and also all negative grounds that go to the computer. did all that with a dremmel tool and it all worked perfect, like a miracle. After about 5k miles it is starting to do this again, not sure what to do.

 

You are going to have a hell of a time replacing the governor solenoid, ect as your truck (assuming the '95) doesn't have a governor solenoid. 95 and earlier trucks have an actual governor. Try adjusting your TV cable and see if that helps.

 

Mind kinda has this problem.. but its when I'm driving through a parking kit it shifts 1-2 a few times till i select 1st gear...

Oh and by the way.. its cummins.. no g there bub... pet pev of mine