Bob Hansen Posted February 4, 2004 Share Posted February 4, 2004 Whilst driving down the highway 4th (OD) went away, just like it was neutral. Drive (3rd) and reverse still work, although drive seems to slip under load. It did start to work normal then went out again this happened 2 times. Pulled trans pan off, fluid very red and hardly no debris or gunk in the pan or screen. The throttle valve moves freely & the shifter linkage seems fine. Question 1) Could this be as simple as a blockage in the valve body? Question 2) Anyone need 1986 S-10 Blazer parts? Everything is good except the trans Quote Link to comment Share on other sites More sharing options...
Grease Posted February 5, 2004 Share Posted February 5, 2004 Bob i would hazard a guess that the 3/4 clutch pack is gone. all forward gears operate thru the forward clutch pack and you say the other gears work.4rth/od requires the 2/4 band to engage and the 3/4 pack to engage .the 2/4 band is operated sepratly for 2nd and 4rth. if you have second gear the band should be ok . if the band doesnt engage for 4rth you should continue to move in 3rd...not like a neutral condition. you say it seems to slip in 3rd also which again requires the 3/4 pack to engage. Heres the diagnosis from GM book NO 3-4 shift/slipping or rough3-4 shift 1 GOVENOR weights binding GOVENOR valve stuck GOVENOR drive gear retaining pin missing or loose GOVENOR gear damaged GOVENOR support pin in case to long or to short 2 OIL PUMP ASSY faces not flat pump cover retainer and bail assy omited or damaged 3 VALVE BODY ASSY valves stuck 2-3 shift vavle train accumulator valve throttle valve T.V.limit valve 1-2 shift valve train 3-2 control valve manual valve link bent or damaged spacer plates or gaskets incorrect,mispositioned or damaged 4 2-4 SERVO incorrct apply pin missing or damaged servo seals porosity in pistons. cover or case damaged piston seal grooves plugged or missing orfice cup plug 5 CASE 3rd acumulator retainer and ball assy leaking porosity in 3-4 acumulator piston or bore 3-4 acumulator piston seal or seal grooves damaged plugged or missing orfice cup plug resticted oil passage 6 INPUT HOUSING ASSY refer to slipping 2-3 shift 7 2-4 BAND ASSY worn or misassembled i know this is getting long . yes you could have a valve body problem . but likley the trans needs rebuilding . mike Quote Link to comment Share on other sites More sharing options...
Bob Hansen Posted February 5, 2004 Author Share Posted February 5, 2004 Thanks for the detailed input Mike! To me it feels like a pressure issue/ When I place the shifter in the 4th gear position (OD) it does not engage. It seems to slip under load when in drive or reverse. Yet twice it temporarily worked normal after the initial time it went out. It did not work normal for long, when I accelerated it "popped out of gear" so to speak and I had to place the shifter in the 3rd gear position (drive) to continue. Up until this the all shifts were fine including the 3-4 shift and convertor lock up. At this point I have nothing to lose by dropping the valve body, & looking around for something "stuck". Quote Link to comment Share on other sites More sharing options...
Guest Posted February 5, 2004 Share Posted February 5, 2004 I have to remove my valve body because there is somthing stuck in there. When you have your off, take a small screwdriver(s) and carefully without raising any burrs, try to move the valve rods. They should move fairly easily, which means that they are OK. If you find one that is kind of stuck, you need to clean it out. It dosn't take a very big particle to cause problems. Quote Link to comment Share on other sites More sharing options...
Grease Posted February 6, 2004 Share Posted February 6, 2004 Bob ...be sure to check the TV cable adjustment that is probley the most critcal part of a 700.over the yrs GM made many upgrades to this tranny . in the couple i have in use i do a vavle body upgrade when the trans were rebuilt.this is NOT to make hard tire burning shifts.it is the installation of the NOYOYO SysKoKal Kit a SHIFT CORRECTION and CALIBRATION kit , from TRANSGO ( trans parts company, and probly from other suppliers as well)this kit is part# SK700. it has detailed intructions and lots of springs.several oring type seals to replace stock parts. it does take several hrs to install.you may not even want to tackle the job . you may have lots of trans experience and that kit wouldnt be a problem for you , but if you dont or others reading this,you decide to remove your valve body just be aware that quite a few steel check balls will be falling out as you seperate the valve body from the trans case .there are check balls on the both sides of the spacer plate . i can't at the moment recall how many but you will need a book with the info as to where they all go . good luck mike Quote Link to comment Share on other sites More sharing options...
Guest Posted February 6, 2004 Share Posted February 6, 2004 sorry about the 700 bad luck!!!!! we run 700`s in all the streetods and restro`s we build! follow the above posts directions he is telling a very good point take note you need to be very experenced i have built about 60 of these in the last three months this is your problem 4th gear clutch pack is week under preasure when u pull it apart be sure and look at you intermetiat clutches if you will be beef them up a little they are bullet proof one of our door slammer braket drag cars (670 hp) is running one it`s satying together i can help you out on all the tips and tricks!!! Quote Link to comment Share on other sites More sharing options...
MeanMonte Posted February 10, 2004 Share Posted February 10, 2004 A sales rep from jasper engine brought a valve body by our shop and showed us that something as small as a human hair can stick a valve very easily. just to keep in mind if you rebuild your own tranny Quote Link to comment Share on other sites More sharing options...
Bob Hansen Posted September 16, 2004 Author Share Posted September 16, 2004 Well the transmission seems to have fixed itself OD now works as it should. My son (Rob) was driving it and while cruising down the road with the shifter / trans in 3rd, he floored it (mind you this is a 2.8 in a 4x4 S10, so putting it to the floor will get you to 60 mph after a little while)and he shifted into OD (Drive / 4th) and it shifted and has been working fine for 2 days now Quote Link to comment Share on other sites More sharing options...
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