1986 Strange Tranny Problems

After driving around in my '86 suburban through the heavy snow after a recent blizzard, my transmission began acting strange. Now, while if I'm driving in 2WD and brake fairly hard to a stop, none of the gears work. However, if I grind into L4WD, all the gears work once again. The fluid level is correct. Any ideas?

After driving around in my '86 suburban through the heavy snow after a recent blizzard, my transmission began acting strange. Now, while if I'm driving in 2WD and brake fairly hard to a stop, none of the gears work. However, if I grind into L4WD, all the gears work once again. The fluid level is correct. Any ideas?

Check the vacuum line to the transmission. You may have knocked it off.

Just guessing, but an '86 MAY have the TH700-R4, and therefore use a TV cable instead of a vacuum line to a pressure modulator. Does the trans seem to operate normally if you manually run through the gear ranges?

Can't speak for all of them by my 86 burb has the 700R4 and definitely does not perform without the TV cable. It's attached to the throttle linkage but instead of going into the cab it goes down into the trans on the passenger side. Check to see if yours is broken.

Sounds like a transfer case problem to me.