95 Blazer 4x4 trans problem

i have a 95 blazer 4x4 there is something wrong with the transmission, it will go into gear and move about 20 - 30 feet going forward or reverse but then it wont go any farther its like all of a sudden the tranmission isnt engaged any more. can anyone help me diagnose this?

Mileage?

Service history?

Trans model?


Codes?

the mileage is around 160xxx im not sure of service history (its my buddys truck) , its a 4l60-e trans and when i scanned for codes all it pulled up was an engine knock sensor malfunctioning

I have a 95 jimmy. It has the 4L60E as well. My transmission was acting up too. A filter and fluid change with a quart of Lucas transmission lube cured mine. My problems started around 180000 miles. Converter chattering, no reverse. sluggish forward gears. I ran the Seafoam Automatic transmission additive in it first to clean the valve body then changed the filter and fluid. I have over 200K on it right now and it shifts and runs great. This might be a good fix if you don't want to do an overhaul on it. It cost less than $100.00 if you do it yourself.