VE 5 speed auto to 6 speed auto conversion.

[J_D 2.0]

Hi All.

Im looking at converting my SV6 from the 5 speed auto box to a 6 speed auto box. I know your thinking “why would you possibly want to do that” to which I would say the 5 speeds are rare as rocking horse sh1t and expensive af whereas the 6 speeds are a dime a dozen.

The box that’s in it is on the way out and a reco 5 speed box is 4k, a good second hand one (if you can find one) is nearly 3k from what I can see. If I’m into the SV6 for the long haul (and I am) I’m better off changing to a gearbox that is more common.

I suspect that not too much mechanically would need to be changed but how would the electronics be dealt with? Can you just get an ecu from a VE S2 and use that? Would you reprogram the existing ecu?

On the cost differentials alone if I can do the conversion for 1500-2000 plus the cost of the gearbox at around 1000-1500 I’m ahead and get the bonus of an extra gear plus easier servicing/replacement down the track.

 

[Fu Manchu]

Will watch carefully. My $3k rebuilt 5speed gearbox just **** itself after 2 years and the workshop that did it has closed down.

I’d be most interested in hearing if the ECM can be reprogrammed to run the 6 speed.

 

[Lex]

I’d be most interested in hearing if the ECM can be reprogrammed to run the 6 speed.

I don't actually know the answer to this question.
But, my uneducated guess would be yes.
Or when buying the 6l50, also buy the harness & ecm that matches your motor & the 6l50. The matched set. Then when everything is installed, then link everything that needs linking?

 

[Fu Manchu]

Those ECMs run a direct injection system and a totally different motor from an engine management position. May as well be running a V6 using an LS1 ECM.

I think the only way would be a tuning guru to weave some magic with the existing modules.

 

[Lex]

Those ECMs run a direct injection system and a totally different motor from an engine management position. May as well be running a V6 using an LS1 ECM.

I think the only way would be a tuning guru to weave some magic with the existing modules.

Maybe l just used the wrong word. He has a sv6. I imagine there are motors that are the same as his, but with a 6 speed auto?

 

[Fu Manchu]

No. If it had a 5 speed, they were only offered at that time with 5 speed and the LY7.

The 5 speed LY7 powered series 1’s had a “Sports mode” feature that livened things up a little.

This feature was not required with the 6speed and deleted from high end models.

There was a series 1.5 that introduced a 6 speed and the newer direct injection motor.

Series 2 had visual differences and the 6 speed with the newer engine.

 

[J_D 2.0]

Will watch carefully. My $3k rebuilt 5speed gearbox just **** itself after 2 years and the workshop that did it has closed down.

I’d be most interested in hearing if the ECM can be reprogrammed to run the 6 speed.

I’ve contacted a company in the states who makes a computer/harness to run the 6L50 box. They reckon if your Holden Commodore is post 2007 it can run the 6L50 with the GM ECM (response below). They didn’t elaborate on if programming is required so I’ve asked the Q. Will let you know the response.


“The TCM2650 will get it working, but if you have a 2007 or newer Holden and are running the GM ECM you do not need the TCM2650“.

 

[J_D 2.0]

Thinking out loud I would hazard a guess that there cant be too much difference between ECMs from the beginning of the VE series in 2006 up until the VF was introduced. ECMs are quite complex and I can’t see GM making bespoke ECMs to suit each variant of the VE.

They would probably have one ECM and just modify the inputs/outputs (and wiring) accordingly. Which should mean a suitably qualified programmer would be able to make the stock ECM work with any other stock component from the same vehicle model line. Worst case scenario should be some extra wiring and programming.

If I have to pay someone a couple of grand to rewire and reprogram I’m still ahead. If its just plug and play and a bit of programming it’s a no brainer and more than could be hoped for.

 

[J_D 2.0]

Those ECMs run a direct injection system and a totally different motor from an engine management position. May as well be running a V6 using an LS1 ECM.

I think the only way would be a tuning guru to weave some magic with the existing modules.

I don’t think there would be that much difference between port injection and direct injection from a computer standpoint. The sensors would be the same, just the injection pulse timing and duration would vary between port and direct injection.

 

[Lex]

I don’t think there would be that much difference between port injection and direct injection from a computer standpoint. The sensors would be the same, just the injection pulse timing and duration would vary between port and direct injection.

These electronic transmissions work of tps & rpm. Then a heap of other stuff.