Hi everybody, I need some help (sorry about the length of the post). I recently put my 85 Z28 back on the road after sitting for the past 1.5 years in my parent’s garage. The car is in overall very good condition, engine runs great, never had any transmission trouble it is 100% stock w/ LG4, cc Q-Jet, and what I beleive to be the 700R4 transmission. I changed the oil, checked fluid and brakes and took it on its first drive. It ran well but transmission shifting seemed sluggish. I didn't think anything of it and drove it back to my house about 1 hour away from my parents.

The next day I drove to work (about 7 miles) and the car ran well, the same as it had the previous day. On the way home about halfway through the drive the car stopped going into overdrive, confused I tried shifting from drive to overdrive but to no avail. About a mile later after stopping at a red light the transmission refused to shift into any gear, STUCK IN FIRST, but it wasn't locked in first, ie: when letting off the throttle the engine would return to idle but when applied again the engine would rev all the way up to yellow line (4500 rpm) still with no shift. I babied the car the rest of the way home (in 1st gear).

Once home I shut off the car and checked the transmission fluid, realizing that I had forgotten to check it when I pulled it out of storage (How dumb is that?!!). Of course it was extremely low, so I went and bought transmission fluid and it took 3.5 quarts to bring it back up to the "full when hot" level.

Today I took the car out for a drive (happened to be the same route I take to work) and on the way there the transmission was shifting but only at very high rpm and very hard, and no overdrive. On the way back it was doing the same thing and I stopped for gas. When I resumed driving I had the car in drive not overdrive, once I got to about 55 mph I shifted into overdrive and the car shifted into overdrive. I came to a stop light and started normally, transmission shifted smooth, through all gears all the way to 55 where it shifted into overdrive, PERFECT! or so I thought. I decided to apply some throttle to pull it out of OD and then see if it would go back in. It did not, and at the next red light the transmission was back to the way it was, revving real high before shifting hard. Not sure what this means or how to correct it, since it suddenly shifted normally for a few minutes I don't think I'll need a rebuild, then again I really don't know anything about transmissions.

Thanks everybody, any thoughts on what this might be would be greatly appreciated, I'm not sure where to go from here.

 

An update for anyone who happens to read this in the future. I took the car out for a nice long drive (about 1.5 hours) and at some point, I guess when the transmission got hot enough it started working normally. Overdive, shifting, everything, its been fine for 3 days now so I think I've gotten very lucky.

 

Check your TV Cable

 

Sounds like the TV cable was acting up to me as well. Either that, or you had some sludge stuck in the valve body somewhere from it sitting for a while. Either way, you got real lucky that the clutches didn't get fried running it that low on trans fluid!

 

No question about that. Thanks for the replies, 1 week later and still no other problems I'll keep my fingers crossed, should probably change the transmission fluid/filter though just to be safe.

 

If the fluid looks & smells fine, leave it alone.

 

I had that similar problem when I installed a new motor in my 88 IROC. It was in fact the TV cable just needed to be adjusted. I hit the reset on it, (holding the throttle all the way open under the hood hitting the reset button and then letting the throttle go). I then fine tuned it a little more for a firmer shift and problem solved.