ok no real diag. work done today. i have been doing some reading and did some road tests...i hope this helps pinpoint....i still have no idea..

took it out on highway/street and noticed a couple of things while "testing"

when in cruise (60 - 70) i can tap brakes and it will rev up a couple hundred or so...normal
but at lower speeds like 30 - 50 mph on cruise, when brakes are tapped it will not rev up only drop rpm...mean anything??

then i tried manual shifting thru gears..
between 1st and second it seemed to hang before i felt the shift slight but since i was doing by hand i noticed it. did same thing between 2nd and 3rd...it seemed to hang at the higher rpm ever so slightly....
when down shifting i felt the same thing at the same points....
also if i hold the speed around the shift points...above or below the blazer freaks out...revs up and down like a yo-yo

on a side note...no hot tranny smell today....ughhhhhh

i took it to another tranny shop...and had them drive it with me in car...still no codes.
and yet another bright idea...."well we can rebuild if you want but dont know whats wrong....too many possibilities" i am not mad at shop....just hate guess work

edit: my gas mileage is terrible as well...around 13 on highway...i used to get 17-18 even after the lift.

also i picked up a vibration AGAIN!!! i was looking at the driveshaft and noticed the rear ujoint is loose. the caps that fit under the "removable straps" are loose allowing the joint to move side to side...the bolts are tight and the caps are in place flush with the outer face of the yoke..did i install the wrong u-joint??

if this is u joint <--- (+) ---> then it can slide left to right in the yoke. it seems the joint is to short to fit!!

 

You have described the same problem I have been having almost to the T. I know your frustration all too well. I still need to complete a tune up with new plugs and wires while keeping my fingers crossed but I'm not going to keep my hopes up. I guess we will see what happens. Good luck with everything!

 

Having a similar problem only when engine is cold seems to miss and/or hesitates shifting only till operating tempature is reached.tranny fluid nice and reddish no burnt smells it is full too.thought of trying tune up first don't know if it's ever had plugs put in it I know old owner put cap and rotor on it.let ya know if this helps

 

ok i did some videos to help maybe show whats going on here....

VID 00008 20110918 0529 - YouTube
rpm jump at end is brake tap to stop cruise control

VID 00014 20110918 0559 - YouTube
from stop

VID 00012 20110918 0549 - YouTube
normal accel...shifting seems slow to me.

VID 00011 20110918 0535 - YouTube
ok this one...cruise at 45 or soo...went up hill...cruise kicks in but upon leveling out....rpms stay high till i tap brakes to stop cruise.

if i have to many in one post let me know....i tried to do one for each speed condition.
and one for dead stop to accelerate...on that one notice the high rpm, low speed and delay in speed increase.

********check engine light is for emmisions system...still working on that one...had codes read two days ago..no change. and was there before this problem...i dont think they are tied together at all.

 

warthog
those straps are called dana straps. when you put in a new u-joint did you replace the dana straps as well?
also the caps will not be flush with the outer edge of the yoke, it will be in slightly

 

nope i did not replace the straps....(thanks for the correct term)
ok on the cap placement, wasnt sure...the others are all flush.
i will look at the dana straps and check for replacement.

thanks again.

checked tranny fluid....it was a little high....could that have caused all this? i did radiator couple months ago and added some trannu fluid...i hope i didnt screw this up on my own.

 

np
the strap should only be used once. some caps are slightly smaller. with the smaller caps you will need dana straps that have the extra bit of material on the edge. what this does is give you peace of mind that the u joint will not just fall out

if your fluid is a little high it can cause sluggishness. have you noticed tranny fluid under your truck?

 

no, leaks at all...i let some out thru the cooler lines at the rad disconnect.
will see if that helps...looks like maybe a 1/3 of a quart to high...fluid seems ok.
i am gonna drop the pan and change fluid and filter....

i posted this someplace else, i have read several things that say reuse old fluid on older highmileage cars, which seems counter productive. any truth to that?
i plan on dumping some lucas in with the change.

 

I noticed today while driving in town while raining it surged and missed horribly I'm still thinking I got a bad plug wire

 

I'm not sure how long your SES light has been on, or if this would even relate to your problem.
I have a 2500 Chevrolet Pickup, about 5 years ago the temp sensor went bad and it threw up the SES light. Let me tell you! that thing went nuts after a week of driving without fixing it. Tranny was bumping like mad, It wouldnt even idle right. Unfortunately the truck don't have a tac, so I couldn't actually see what it was doing, but I felt it. Anyway, I put in the new sensor and unpluged the battery ovenight, and it fixed itself immediately..