1992 s10 blazer 4x4 shifts extremely hard into drive and reverse and wont shift into od

SOURCE: 94 s10 blazer wont go out of four wheel drive

The electric shift solennoid on the transfer case is probably bad,common problem with these.

SOURCE: 1993 chevy blazer S10

That is a very common problem with General Motors 700R4 transmission. There is a shell that encases the majority of the forward gears and the reverse drum is on top of it and that completely encases the forward drum. at the bottom of that shell there is a collar that is about one quarter of an inch long that rides on a gear set called planetarys. those have a problem with breaking and cause no reverse and driving in neutral. that is the link between the front and rear shaft of the transmission and the weak link. for that to be repaired it has to be removed from the truck and taken apart. It is highly recommended that it be completly rebuilt not just patched due to all of the metal that is sent through the transmission.

SOURCE: lincoln ls shifts hard into reverse

You will have to have the solenoid body replaced in the tranny and have the PCM reprogrammed.

Harvey N Tawatao

• 3854 Answers
• Posted on May 26, 2009

SOURCE: 4L60E Shifts fine in 1st, 2nd, & 3rd but will not shift into OD

The EMC detected and problem so it's in limp mode, As long as it's in limp mode the 4th and OD will not activate. Take care not to burn up the transmission by running it hard while your in the limp mode.
Your going to have to get the truck scanned to clear any codes and why there are DTC codes. Auto Zone scan for free and most auto shops charge $10.00 to $20.00 to scan sine they want the business.
If you want to clear the codes your self you can put the ignition to the run position and pull the ECM (Batt) fuse out for 20 sec and place it back in then start the truck. It may stall but let it, just start it again and this would have cleared all the DTC code history.
The transmission should be running fine unless there is a problem and the service engine light will be on again and you'll be in limp mode still with an updated DTC in the ECM.
Good luck and hope this helps.

SOURCE: automatic transmission will only shift manually

This is a sensor issue. It can be from a couple of different sensors. The VSS, or vehicle speed sensor is the main one. Loose or faulty wiring can cause it, a faulty PCM can cause it, or the Throttle Position Sensor can cause it.