D40 5th gear jumps out after clutch replaced

[Besty]

Afternoon all. I have just had the clutch replaced in my 2008 D40 6 speed. Now it keeps jumping out of 5th gear. The machanic tells me that isnt from the clutch being replaced but it didnt jump out before the clutch was replaced. Machanic has checked that the gear leaver boot isnt interfering. When under power it stays in 5th, but when there is no throttle, just coasting 70km/hr and above it jumps out of gear.
Has anyone heard of this happening before & if so what is the cure?

 

[4 naving]

If it wasn't doing it before it must be something interfering with the selector. How many K,s have you done?
if its not the lever boot or trans tunnel I would look at the gearbox and engine mounts. if they are broken or worn it could of moved forward when the box was pushed back on. worth a look before blaming the gears, as the boxes in the d40 are pretty good unless you have very high K's....

 

[4 naving]

Oh and did you go the single mass flywheel? the extra vibration could of exposed a pre existing worn gear....

 

[Besty]

Has only done 91000km. Has dual mass fly wheel and a single plate clutch.

 

[4 naving]

How did you go with this....

 

[Filthy]

Same with my d40

Iv just put a smf in mine and is now doing same thing 5th gear only when I back off if any1 nos more let me no also ....

 

[seventies47]

Poor gearbox alignment will cause this issue, normally the box gets jammed on the locating dowels when fitted putting the input shaft slightly out of line. Seen this on a few vehicles now. Loosen all the bell-housing bolts and align properly, then retorque.