Gearbox Change

[RollaDriver]

Hi 

Has anyone attempted to change a T25 (2005) Avensis D4D 5 speed gear box to a 6 speed?

Is this possible?  Does anyone know if the bolt pattern on the flange and the dimensions on the spline are the same and if it can be fitted?

 

Thanks in advance

[Konrad C]

I would say no! I two Google searches for images showing gearboxes for the 1CD engine which is 5 speed, and the AD series that use 6 speed. The bell housing pattern is different, and the starter and drive shaft location are different. The drive shafts may/will need to be replaced. 
I watched a YouTube video from Boggit and Leggit, where he replaced the gearbox from an Avensis to a Verso. Both use a similar gearbox, but he had to make a lot of minor changes to make it fit! 
If you have to replace the gearbox, just use the same from the same model.   

[RollaDriver]

Thank you.  The main reason is I have an issue with the fifth gear on the gearbox where it doesn't stay in gear while driving.  As soon as I shift the gear stick into 5th Gear it forcefully pushes it out.  I am not able to keep it in with my hand.

What could be the issue?  The mechanic doesn't want to open the gearbox as he thinks its a synchro issue.

[Konrad C]

 

[furtula]

5th gear is not used that often, as opposed to 1,2,3, so i would check the cables, as mentioned above.

Usually the slack is under the bonnet, have someone move the shifter and check for any obvious slack. 

Also, have them engage 5th gear, and then when you see which selector moves, try to push it a bit more by hand.

 

[RollaDriver]

I will have them check it.  Unfortunately mine is mostly Motorway mileage so 5th gear got used alot.

Thanks

[furtula]

Yeah, but synchro is in use only when you shift into 5th. 

If it's a synchro issue, you might also expect some noise when trying to switch into gear, grinding, or some resistance in the shift lever.

If you still think that's it, you might try to change the oil in the gearbox 1st, cheaper than replacing the whole box.

[HS78]

43 minutes ago, furtula said:

If it's a synchro issue, you might also expect some noise when trying to switch into gear, grinding, or some resistance in the shift lever.

Not necessarily- My first car was a Corolla Gt-i16. It had an issue with jumping out of 5th gear - this is a well documented issue with these cars. The 5th gear synchro mesh was worn and had to be replaced by a specialist. 

[RollaDriver]

Do you guys know where I can buy the 5th gear and synchro from?

[stefgtir]

Hi I have a 2007 avensis 1.8 and the 5sp gearbox needs replacing as it jumps out of 3rd 4th and 5th gear but finding a straight replacement is proving difficult  so could I replace it with a 6sp,obviously I would also need the gearchange mechanism and cables but would the driveshafts and clutch etc be the same,thanks