Thread: Ecotuning the TD6 gearbox

Been following this too, I had the TCU reprogammed in our other car earlier this year, massive improvement, wanting to do the Rangie now at some stage, been waiting for few extra 'testers'....

I have just read this article and it is exactly what I need. The question is what is the mod and how is it done? Jim

Jim, it is an exchange Transmission Computer (with updated software). Pay your money + bond, they send you a modified ECU, swap it over and send your old one back. They then refund the bond.

The trans ECU cannot be updated via the OBD2 port like the engine ECU. Has to boot directly through the chip. They are only playing with the torque converter pressures (partial lockups) and full lockup, all shift mappings remain unchanged.

I think you should do it and report back

Don't want to put a damper on your enthusiasm, but I believe the main concern with these gearboxes seems that it is:
Underrated for the engine. TD6 is 390Nm; 5L40E is 340Nm. (BMW wisdom?)
Wear of valve blocks.
200,000km??? life.
By lowering/changing the TC slippage and lockup speeds, surely this will only put MORE load on the gearbox components.
BUT if you always drive with a light right foot, then your box may not be overloaded.

I think you will find the main issue with the valves is the soft material the factory made the bits from. If like me you have your box rebuilt with a Sonnax kit and other parts refurbished/replaced/upgraded then this should pose no problem and may improve the gearbox life with less slippage and therefore less heat.

Adrian

I thought that the valve body was part of the housing. Does the sonax kit overcome the wear in the valves?

Originally Posted by jx2mad

I thought that the valve body was part of the housing. Does the sonax kit overcome the wear in the valves?

Yes, the Sonnax kit includes resleeving the valve bores and installing different seals. Tooling up to do the resleeving is the expensive part, which is why it has taken some time to start to see these become available.

I could be wrong, but this may mean you can use different fluid in the trans.

Looking at other car makers who use the GM 5L40/50E's.
GMH/Commodores- Dextron 6, mineral
GM/Cadillac- Dextron 6, mineral or synthetic.
BMW- Dextron 6 Synthetic.

I've just changed the tranny fluid in my TD6 with Nulon ATF Synthetic- meets Dextron 6 specs.
It WAS in a very poor state; clogged filter; brown oil ( not burnt though) and high mileage, 250,000km; no history available, but I suspect not changed for quite some time! Has jerky downshifts, particularly if using the "manual" changes, high T/C stall, high lockup speed.