TD-W8901G and TD-W8960 use different chipset from different manufacturer.
The bridge function of them are not compatible with each other.

flying snow wrote

TD-W8901G and TD-W8960 use different chipset from different manufacturer.
The bridge function of them are not compatible with each other.

many thanks , I didn't think of the chipset difference.

I guess my TD-8840T and the Billion 8800NL have the same chipset as the W8901

How did you setup the TD-W8960N to bridge mode?
It has no compatible issue if you use wired Ethernet to bridge them.
Normally, just need to turn off the DHCP server on TD-W8960N and plug the TD-W8910G to one of the lan ports of TD-W8960N.

it's the TD W8901G that's in bridge mode.

it's worked fine with a wired connection with 3 different main modem / routers over the years

the DCHP is disabled and ip address set outside the DCHP range of the main router.

the new TD W8960N will connect briefly to the 8901 but the LAN looses connection or freezes,

sorry, misunderstood your question.
Is the TD-W8960N connected behind to the TD-W8901G and working as a wireless router?

flying snow wrote

sorry, misunderstood your question.
Is the TD-W8960N connected behind to the TD-W8901G and working as a wireless router?

the 8960 is connected to the 8901 via cable

the 8960 is connected to the internet but I disable the wireless.

the 8960 is connected to the main computer via cable.

the 8960 has a cable going to the 8901 in a different part of the house which is set up in bridge mode to provide wireless to the rest of the house.

wish I could draw a diagram , this is hard work !

in the past I have had 3 different modem / routers connecting to the 8901 with no problem
there is no updated firmware for the v7 8960 , so it looks like a refund , either a bug or fault.

To locate the problem, better to plug a PC to the cable which 8901 is connected to.
Sometimes, if the cable is too long, it will affect the quality of data transferring.