need serious help on this tranny prob.

snooper0069 · April 26, 2004

i have a G.M.C. Sierra 1/2 ton 1500 series. it has the 4l60-E tranny i believe , anyway it is computor controlled. the engine is the 5.7 throttle body. my tranny has been serviced regularly since new . it curently has 143,000 on her now , but performs flawless. it had been 30,000 since the fluid and filter change so i put her in the shop to get this done. i picked it up from the shop and immediatly saw that it now doesnt downshift to first and does not go into overdrive. i called the shop and they told me to disconnect the positive side of the battery for 20 minutes to reset the computer. i did this and still the same thing no 1st and no overdrive. it was perfect until i put it in the shop. anyone who can help me or ran into this problem please give me some idea's. the shop said they would take a look at her again to see if they can locate the problem.

teamjnz · April 26, 2004

I had a shifting problem with my 2000 Silverado and it was the iginition switch. This my not be your problem but you never know.

teamjnz

my post

Frank S · April 26, 2004

Since they changed the filter and it didn't do it before you took it in I'd say something is restricting fluid flow to the valve body and not allowing it to perform properly.

Take it back and tell them because they should fix it up for you.

frdfandc · April 27, 2004

More than likely what has happened is when the old fluid and filter is changed, the clutch material that has worn off the clutches, has now gone down the drain (literally). When the New fluid and filter is added, this further dillutes the "clutch material" that was left in the trans. This sounds like what happened to your trans.