R10 Overdrive Issue

[fredv]

I have rebuilt a R10 overdrive and having an issue regarding the engagement of the OD. When the OD is not engaged with the control handle pulled out, the transmission works fine.
When the control handle is pulled in and when the car reach the speed the OD is supposed to engage, there is a noise which seems to be pinions clash in the OD unit.
The whole transmission have been rebuilt with NOS parts and all electral componants are new, except the solenoid (good used). The wiring is also new and follows the original electric control system.
The relay, kickdown switch, governor and solenoid are working when tested.
All the mechanical and electrical tests described in the shop manual have been successfully performed (OD lever position check, pawl engagement check, governor circuit check, solenoid circuit check, interrupter circuit check).
Note that the transmission has been not tested on the road, but with the car raised on stands.
One more thing, the oil capacity of the transmission is supposed to be 4 pints, but it seems that when I filled it, only 3 pints were sufficient (I filled from the top OD plug until the oil reach the top plug of the transmission case).
I hope there will be some OD experts here to help me to solve this problem.
Thank you for your help