1988 Bonneville Transmission Problem?

A few weeks ago I was driving my 1988 Bonneville when all of a sudden it shifted into 2nd gear. How it only stays in 2nd even when I put it into 3rd or overdrive. I've never had a shifting or slipping problem until this happened.

The local tranny shop says I need a complete overall, but I think it's some other problem. Could the 1-2 shift piston need replacement? Or does this transmission have a Shift solenoid? I believe the transmission is a TH440. Thank you.

no electronic controls on this, more than likely it will have to come apart.

A few weeks ago I was driving my 1988 Bonneville when all of a sudden it shifted into 2nd gear. How it only stays in 2nd even when I put it into 3rd or overdrive. I've never had a shifting or slipping problem until this happened.

The local tranny shop says I need a complete overall, but I think it's some other problem. Could the 1-2 shift piston need replacement? Or does this transmission have a Shift solenoid? I believe the transmission is a TH440. Thank you.


This is usually due to a broken band inside the transmission. It happened alot on the THM 200 & THM 700's.

This is usually due to a broken band inside the transmission. It happened alot on the THM 200 & THM 700's.

This for the reply to my inquiry. Before I take it into the tranny shop for rebuilt, is there anyway to check to make sure the shift solenoid is working? or does the 1988 Bonneville even have a shift piston or solenoid?

This for the reply to my inquiry. Before I take it into the tranny shop for rebuilt, is there anyway to check to make sure the shift solenoid is working? or does the 1988 Bonneville even have a shift piston or solenoid?
As stated above there is no shift solenoid this is not an electronic controlled trans.