Thread: Discovery 2 with new gearbox playing up

Hi guys,

Just finished replacing the gearbox on my TD5 automatic Discovery 2 after the old gearbox overheated and died on the beach. The new gearbox is an Ashcroft Stage 2 ZF 4HP22, with a V8 torque converter (to support the output of my tuned engine).
A few days after I started driving again, the car started playing up when taking off at intersections. The problem seems to be random, some days it doesn't happen, others it's quite bad, and it doesn't seem to correlate with speed or engine temp.
It feels like it's in one of the higher gears and accelerates very slowly, before finally changing into 1st jumping forward as normal. Previous gearboxes have also had this issue, but have had a spike of revs between changing gears and a big thud when it goes into 1st. The new gearbox however changes smoothly, just not at the right time. Manually selecting 1st doesn't fix the issue either.
I have checked for faults with the Nanocom, and nothing comes up. I also spoke to a transmission mechanic in Acacia Ridge that thinks it may be an issue with how the ECU/GCU may be communicating with the box.
Does anyone have any suggestions for what else I can do to diagnose or fix this? Don't want to be damaging the new gearbox by driving it around for too long with the issue.

Thanks in advance

Sorry for late response.

I've checked fluid level, and it was both full and clean. Problem is happening less often at the moment, but still pops up from time to time.
My father thinks it may be turbo lag because of the V8 torque converter. I feel like it's too severe when it happens, but thought I would get an opinion from you guys too.
Have been consistently checking for problems with the Nanocom, will try resetting adaptive values tonight.

Thanks for all the help so far,
-Redford