QuestionHi, I have a 1969 MG Midget that jumps out of 2nd gear on a trailing throttle. All other ratios are good and 2nd is no problem as long as you keep power on.
Any advice on a fix, is this feasible for the home mechanic or is an exchange box the only answer?
Cheers
Jon
AnswerHi Jon,
There are several possible causes for this.
The easiest and cheapest to repair is a shift lever can foul in the shift tower cover when the engine or trans mounts are a problem, thus on deceleration, the engine and trans moves enough to kick the shift lever out of gear. To test this, remove the shift tower cover and drive the car.
The other possible causes that I have run across are inside the gearbox and require that the transmission be disassembled.
One is loose lateral play in the main shaft (for what ever reason) and the other is the spline teeth that actually engage 2nd gear get worn at an angle and "walk" out of gear. The angle they are worn determines if it jumps out of gear on acceleration or on deceleration. The cause is either a driver who "speed shifts" (in either direction up or down) And/Or drives the car for an extended period of time with a dragging clutch.
Improper down shifting is also a contributing factor. With syncros as good as they are in most gear boxes, down shifting is a lost art. Read my "Tech Tip" on how to make a straight stick gear box last.
http://mg-tri-jag.net/tech4.htm
Most DIY mechanics can change a gear box by removing the engine and box together. You should first purchase a repair manual.
Howard
