Installing 392 8 speed trans into 5.7 with 8 speed

[james1595]

I am swapping out my old 8 speed transmission with a 8 speed from a 1320 392. Is there anything I need to do for the swap? I was told I may need to flash the tcm. If so how would I do that?

[LilSick]

i would not do anything to it...

i would bolt it in and buy another 4 credits.


then i would get Don to tune it for you : )

[LilSick]

*did you get the convertor too?

might wanna consider buying a 3400 since the trans is going to be removed anyways?

tuned right you can roll into it and it will pull away from a stop like it did stock

stab it and there better be traction available : )

i might be able get you a lil break on one

[james1595]

It came with the stock 1320 convertor. So I don't have to change anything? Just bolt it up and flash a tune

[LilSick]

A HP70 is a HP70

Where do you want to shift?

[james1595]

Ok. I've been told I had to flash the tcm. And not sure, depends where it makes power. Right now it's 6600, but I may go higher

[LilSick]

Someone with a stock 5.7 would have to recalibrate

You are already shifting yours at 6600

Or trying to : )

Stock 5.7 would run into the limiter long before that

That’s why the PCM has to be tuned simultaneously with the TCM

[james1595]

Ok. It shifts at 6600 2nd threw 5th. But, I figured for the price, I got a 1320 convertor and a lower milage trans

[LilSick]

if you just bolt it in it should shift at 6200 to 6400

depending on the mode...

and maybe the mood ha.


whoever said you would have to flash it was prolly referring to the glitch

most 1320's have a 2-3 glitch with the stock tune

its intermittent

some 15-17 scat packs have it too

seems like it comes from trying to have the controller offer such soft minimal throttle shifts

i can usually get rid of it with a trans tune

[james1595]

Ok, thanks for the info