700R4 Issue..Help Please!!!!

[jmh1972770]

The 700 in my 84 K10 won't hold third when placed in the "D" position.It only does this under 50mph.Over 50,I can manually shift from O/D to D and it'll shift into third ,lock up and stay in third until I place it back in O/D.But under 50,it'll stay in 4rth.From a complete stop with the selector in the third "D" position it'll shift the same as when its in the 4rth"O/D" position.It's OK for highway driving but sucks when driving around town.The trans upshifts fine trough all 4 gears with no slipping. It downshifts from2-1,3-2,4-3 and even 4-3-2 once,like it should.The TCC locks up in 3rd and 4rth like it should and unlocks as soon as I either press the brake or gas pedal.I can feel the detents on the trans when I shift it to "D" manually.I've gooogled,binged this to death and have yet to find anybody with the same problem.Any suggestions?

[bake74]

     That is a new one to me, sounds like it should be the other way (wont shift into od), someone will chime in and have something you can try I am sure.

[zieg85]

     That is a new one to me, sounds like it should be the other way (wont shift into od), someone will chime in and have something you can try I am sure.

I was thinking the same thing.  I have a TH350 with no second gear.  Goes from 1st to third.  If you manual shift it to 2nd gear it still stays in second.  I still haven't had anyone tell me what might be going on.

[bd]

Here are a few thoughts.  Pull the dipstick and look at the color of the fluid.  Smell the fluid.  If it's brown and smells burned, clutches have been slipping.  Drop the pan and look for an accumulation of debris settled to the bottom of the pan.  DO NOT wash out the pan!  Look for steel (magnetic), aluminum (nonmagnetic), brass (bushing material), black or brown paper flakes (clutch material), rubber flakes (seals) and hard parts.  If there is a lot of debris, it's time for an overhaul.  Bundle the pan as-is, with the debris intact, so your transmission shop can look at it.  You may have a valve sticking in the valve body, and/or there may be internal leakage.  The MD8 has, among other issues, inadequate support of the input shaft that can result in wear, then leakage past the teflon shaft seals as the shaft gets sloppy.  Do you have fluid leaking past the pump seal?  Has your trans ever been out for repair or exchange?  How long has it been since the trans was serviced?  How many miles on it?

[VileZambonie]

     That is a new one to me, sounds like it should be the other way (wont shift into od), someone will chime in and have something you can try I am sure.

I was thinking the same thing.  I have a TH350 with no second gear.  Goes from 1st to third.  If you manual shift it to 2nd gear it still stays in second.  I still haven't had anyone tell me what might be going on.

Zeig your problem is in the intermediate clutch circuit

jmh1972770 What's been done to the valve body?

[jmh1972770]

Thanks for the replies. Nothing has been done to the valve body as far as I know.The previous owner had it rebuilt 5 years back the only thing I know that he did was wire up a tcc lockup kit,other than that just a basic rebuild.I changed the fluid and filter 3 months ago and probably haven't put 1500 miles on it.The old fluid did have a brownish tint to it but no debris in the pan.Thefluid level is normal now and the fluid's red,allbeit a dark red,but I didn't flush it or the converter so I figured it was some old mixed with the new.It probably does need a rebuild,but it'll have to wait til spring.