Weird Auto Box Question (definitely not the Governor Computer)

["jamesrguk" <James_rg@xxxx>]

Hi all, 

I recently had my auto box Computer changed for a custom made new 
one here in the UK which has brought the car back to life after a 
long spell of being stuck in 2nd or 3rd. Anyway the problem I now 
have I am sure is not related to the CG unit, when I drive the car 
on the motor way and I am overtaking someone I often find that 3rd 
just hasn't got enough acceleration. At kick down the box shifts 
from 2nd to 3rd at approx. 4000 rpm, but there is still more 
acceleration in 2nd than 3rd up to about 4700 rpm.
I.e. When I overtake on the motor way, and I know it is safe, I will 
manually shift the lever from 3rd to 2nd and overtake. However after 
approximately 20 mins of driving I loose the ability to manually 
shift the gears until the car has sat and cooled off (I CAN move the 
stick but the gears won't change). During the period where I can not 
shift manually the box will still kick down and shift correctly 
using all 3 gears.

So it would appear to be a temperature related issue.

Any Ideas?

Thanks in advance


James RG