MG TF gear stick gets stuck

[mgtf160p4lcw]

MG TF 160, gear stick gets stuck after 10 to 20 miles, on 3rd 4th 5th checked gear box levels, clutch levels, this happens when car runs at normal temperature, very smooth through all the gears before that, including reverse, no managements lights come on, advice welcome, cheers,

[mgtfnut]

When you say stuck, do you means the gear lever locks up and won't move about at all, or possibly you find it difficult/impossible to engage a gear and the gear lever moves between selection positions?
The car is of an age that engine management lights are not on the menu - except for oil pressure, coolant temperature etc!!
Does it start off ok first thing and then develop, or is it totally at random? You say it is ok to start with, but is the clutch action smooth and quiet, or stiff and sticky? Is gear selection possible with engine off without any sensation of stiffness or reluctance to engage gear?
First thought is clutch operation, possibly the old sticking clutch operating lever in the bell housing problem. It could be limited clutch action is preventing gear engagement by the syncro cones blocking the gear change.

[mgtf160p4lcw]

When you say stuck, do you means the gear lever locks up and won't move about at all, or possibly you find it difficult/impossible to engage a gear and the gear lever moves between selection positions?
The car is of an age that engine management lights are not on the menu - except for oil pressure, coolant temperature etc!!
Does it start off ok first thing and then develop, or is it totally at random? You say it is ok to start with, but is the clutch action smooth and quiet, or stiff and sticky? Is gear selection possible with engine off without any sensation of stiffness or reluctance to engage gear?
First thought is clutch operation, possibly the old sticking clutch operating lever in the bell housing problem. It could be limited clutch action is preventing gear engagement by the syncro cones blocking the gear change.

Starts no problem, up through the gears and down, also reverse ok, very smoothly then after 10 to 20 miles it can lock in the gear I might be in say 3rd trying to go up or down the same happens on 4th and 5th, pressing the clutch all the way down and up a few times, makes no difference, so I depress the clutch down and coast for a time, say sometimes 5 seconds to 10, and the gearstick frees up for me to choose the next gear I need, say up or down, All gears are free when engine is turned off, I will be looking at various things in the next couple of day's, Hopefully all will be sorted for Silverstone,

[mgtfnut]

If it were me, I'd take the engine hatch off and get someone to press the clutch pedal and you watch the slave cylinder pushrod movement.
Might be some seal wear and leakage in either or both the master cylinder and slave cylinder.
The temperature effect could be differential expansion of the ali bell housing and the steel shaft as it warms up. Lack of lubrication is normally the problem, hence the profusion of greaseable replacement steel shafts. In some cases they have totally seized up.
My money would be in this area But I could be completely wrong
You could check the run and location of the two gear change cables and possibly get under the car while another person shifts gears to see if there is any obvious malfunction.

[EllsoJo]

mgtf160p4lcw
You mentioned:
"so I depress the clutch down and coast for a time, say sometimes 5 seconds to 10, and the gearstick frees up for me to choose the next gear I need, say up or down, All gears are free when engine is turned off"

That seems to indicate that either the gear selector shaft, OR some linkage inside the gearbox is jamming once the engine has been running AND GEARBOX have been rotating for a while and warmed-up.

Have you tried changing gearbox oil.

It would be interesting to know how much oil is in your gearbox. Drain into a container and measure?