i don't think there is anything wrong with the tc lock up and the tranny works just fine cold but when it warms up thats when it acts up and runs at 3100 rpm doing 70 mph

 

I just looked up on auto zone .com and the filter kit witch comes with the new gasket. Get one of those little packits at the checkout counter of silicone. And all that will cost a whoping $18. Then if you spring for the lucas add $8 to the total. An again take your time with the filter. It makes a huge differance.

 

When the transmission fluid is cold, it is more viscous. If your problem exists only after the vehicle comes up to temperature, you likely have pressure leak somewhere that is not allowing 4th to apply properly once up to temperature.

Ex. A seal leak on the 2-4 servo or 4th accumulator, badly worn bore on the 4th accumulator, etc... Most of this could be checked/replaced without rebuilding the transmission, but you have to know what you are doing inside a modern automatic to not cause more damage than has already been done.

Bad news is that if it isn't an all out seal failure, but just enough to not fully engage 4th gear, you could be eating away at the band, shortening its life which means a full on rebuild may be in your future anyhow.

 

I'm sorry, Evo.. but YOU DO have a transmission problem. Why we are all saying Lucas AT fix.
It wouldnt hurt from your description to add a/more tranny cooler, in addition to the Lucas, like I did on my bird.. which had a very SIMILAR problem and I drove another 150,000...One hundred fifty thousand miles!!!! without doing anything else.

As Kyle says, you have a rebuild coming up ANYWAY if you dont use it. Therefore why are you splitting hairs?
It will take up to several hundred miles for the effect to show.

Times wasting! It aint getting better by talking about WHERE AND WHAT IN THE TRANSMISSION is slipping

How it works: Swells clutch and seal materials. Somehow without making them more brittle and, as you will see, adds viscosity.

 

1:100K recomend for fluid/filter change?Were the hell that come from?Every chevy/gmc manual even the one that comes with the blazer/s10(and ive had 17 so far) Tells you to drain and change fluid n filter every 30K,I pull bobcats and 3-4 ton trailors of rebar and stuff with half yard of sand in the bed,Cant go over 35 since front tires off the ground but ive gotten over 300K from every one ive had thats been automatic,the 5 speed manuals i would buy 3 or more a year there junk,the gears are cardboard running a/t fluid,WTH were they smoken on that great idea.Anyways,this is so simple its sick.
160K,Never changed,IT IS BURNED OUT AND HAS NO VISCOSITY LEFT,THICK WHEN COLD,THIN WHEN HOT BUT TO THIN TO PROVIDE PROPER PRESSURE,SO IT IS 18.00 FOR THE KIT,AND IT TAKES 4 1/2 QUARTS ON FILTER ONLY CHANGE,8 QUARTS TOTAL,I RECOMEND YOU BUY 2-4 PAN GASKETS AND GALLONS OF FLUID,AND ATLEAST 1 MORE FILTER,RUN IT FOR 100 MILES,DRAIN IT REFILL IT,RUN IT AGAIN,HELL 20-50MILES WOULD WORK,DRAIN REFILL DRIVE THEN DRAIN AND REFILL WITH NEW FILTER. This way you get 90% or more of all the bad fluid out,also you can do it quicker by draining the fluid lines from radiator but then you have spend the time getting level correct.It will run fine once you have good fluid again but if it continues slipping at running temp then your torque converter is on its way out or all the times it struggled to hold and lock on highway running it might of glazed the flywheel as well.
Lucas works great,but it eats up the seals in the long run and anything else made from rubber and plastic and cardboard but most ppl by that time need new tranny anyway.Older rides and v8 trannys like his tbird were what lucas was made for,they havent changd there formula in what?30 years plus while were running on cardboard n not metal these days,lol!
Anyways hope this straitens out this thread for the next person that wastes 20 mins. thanks and god bless and change your fluids,diff`s do when u do tranny,oil n filter every 3K or i can show you motors at 100k looking like 500k cuase dealers are telling 7-10k oil changes,whos profiting off that one? and every 1 i`ve owned the tach has wound up doing crazy readings the older it got,HELLO PPL,MAYBE ELECTRONIC BUT STILL USES SPRINGS,SPEEDO ALSO,MINES AT 90MPH WHEN I`M DOING 81 AND I`M AT 194K NOW,REPLACED THE SENSOR MADE NO DIFF,IF I WAS RICH I WOULD FABRICATE AND SELL THESE DASHES BUT USEN CABLES AGAIN N INVENT ADAPTORS FOR THE HOOKUPS ON THE TRANNY AND ENGINE AND THE CODE TO KILL THE PCM PART,LOL!
STAY CHEVY,STAY BLAZER/S10,THINK B4 U WHINE N ARQUE,N GOD BLESS!