hello all. i just bought a 97 blazer to haul my dogs and pull my 4 wheeler. it has 189k on it. The tranny is supposed to have around 50k on it.

my question is when i'm driving it at a consistant speed under very light throttle (like how you would just to maintain speed) it sometimes likes to downshift and then upshift over and over. it will be sitting at like 1100 rpm downshift to 2k rpm and then shift back down to 1100. Is this a throttle position problem? ecu issue?

under normal acceleration it shifts and pulls great. just sometimes does this under very very light throttle. any help would be great!
thanks
matt

 

i notice it only does it between 3rd and overdrive. when i drive in just 3rd its fine. when i put it in OD it starts to act like that sometimes. any help?

 

my 98 jimmy does the same thing . i would like to know why also ..

 

your solenoids are bad its an easy fix go to your dealership or transtarindustries.com and they run ne where from 15 to 30 bucks

 

can you elabotrate a little? what solenoids? is this something that a trans shop will be able to detected with there scan tool?

 

my 97 does the same thing!!
only difference is that mine kicks on the CEL which reads that my trans 4th gear is slipping.
rumors suggest the solenoid is going. i'm thinking replace trans.
i hoping that smrtrbl86 is right!!

pls share !!

 

well i took it to a bery good trans shop and they said the tranny is fine, they did pull some codes (athough i had no SES light). Evap, o2, and misfire codes.... i changed the plugs,wires, cap and rotor..all ac delco parts..i even pulled the throttle body and cleaned that...it was caked with build up. there is def. more power now and runs smoother but its still doing the same thing...like the torque converter is opening and shutting... its really noticable at 50mph... any ideas? i still have to change the o2s.

 

What happens if you just tap the brakes (just enough to trigger the switch, but not enough to slow you down at all)?

 

well as soon as i tak my foot off the gas it will sit back at the normal rpm in overdrive at 50mph.... if that make sense. it only does the rpm jumping in overdrive under light throttle. very noticable at 50mph. i think i need to change the 02s 183k and they don't look like they have ever been off. i can't get them off right now. i'm gonna have to use some heat..

 

Tapping the brakes (while maintaining throttle position - I did not mention that) should cause the torque converter to unlock. You should see an increase in RPM when the torque converter unlocks.