old mechanic
01-06-2004, 06:22 PM
hi ,ive had this problem with overdrive on 250 th locking up off and on constantly for about 2 yrs,very eratic , i just found the cure by accident ,i looked up an old tech bullitine and it says greese speedo cable and reposition end towards trans so there are no sharp turns ,also replace vehicle speed sensor behind instrument panel, my wires were cut almost in have from factory by sharp brace ,sensor is till avalible from gm ,sensor is a pain in the b-tt to get too but remember computer has to know what speed and close or open loop to ingage o.d ,it worked for me