Hi Guys,

I do not own a bonneville but I am using the 4T80E in my engine swap and I cant seem to find what controls the transmission. Does the 4T80E in the bonneville have a tcm (transmission control module) or is it controlled by a different module? If so, what module?

Thank you for your assistance.

The 4t80 transmission is not really my area, but looking threw my service manual for that transmission I do not see a separate control unit for the trans. So it should be controlled by the PCM that also controls the engine.

Well, then what would be the best method of controlling the transmission.

I am pairing a 3800 (n/a Series 3) and a 4T80E (yes I know they arent an exact fit - but all but one bolt lines up and I will make a bracket connector for that one bolt and the hard parts on this trans are more durable than a performance built 4T65E and the 4T80E has a better chain).

Because of the swap; I will have to use a series 2 pcm and a series 2 wiring harness from the 3800 along with the throttle body from a series 2 because I have to have a cable controlled throttle body.

Can I run the engine with the series 2 pcm and the transmission with the stock pcm in the bonneville? ... Little confused as to how to get it working in terms of electrical and computers.

the 4T80 may run on the S2 PCM but you will have to have the gear ratio changed in the PCM from what ever it is now to the 3.42 or 3.73 gear ratio of the 4T80. do you already have the 4T80?

No, I do not have the 4T80E yet; I plan on purchasing a low mileage (under 20k) transmission from a gxp bonneville from a junkyard. I believe the bonneville used a 3.71? Someone please confirm if you know. I am not sure of the gear ratio of the series 2 grand prix but I am assuming whomever I have tune my car would easily be able to define the new gear ratio?

If I'm not mistaken a GP trans is 2.93 gear ratio. Another option for the 4t80 is manual control, it'* a bit pricey, but might work for you. http://www.e-transcontrol.com/mcu-0806.htm

Thank you, the g6 I drive has this functionality. However, with the g6 it has a "m" mode where you select the gears by moving the shifter up or down. And when it is in D it drives completely automatic.

With a module like that; will it allow completely automatic and then driver shift control? How to you "engage" dsc?

The 4T80E has an internal TCM. Not a tranny guy but google, is your best friend.

Theses guys sell controllers for it.

http://www.black-ridge.com/wiring-and-harnesses.htm

Dan has some great info, John pulls out a link to info... To contribute in this thread, the bar is pretty high.

Here'* a members thread about using the 4T80 with a 3800, hopefully that helps to answer some of the questions and maybe see how someone else solved the issues.
https://www.gmforum.com/showthread.p...highlight=4t80

Yep, he'* the one that pointed out that link to me. He'* had some crazy projects.