Rockrz

I have a 2009 Chevrolet Colorado with the 5.3L 4 speed auto that I'm on a tweak seek to get better overall performance / efficiency without breaking the bank... and the thought came up concerning adding a 6 speed auto tranny, but after reading this thread, it seems to be very expensive - https://ls1tech.com/forums/automatic...auto-swap.html

So, what do you guys think about bolt on gears like the folks here offer?
http://www.gearvendors.com/hrgm4s.html

I didn't read all of it, but it sounds like this setup would bolt on to the back of your existing tranny... if this is a workable solution, would a lot of re-tuning of the ECM or BCM been needed?

Just wanted to see what the consensus is on this type of setup, or if I should be looking at other options?


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mrvedit

I don't think adding a Gearvendors overdrive to your existing setup would give you anything of value, much less satisfy you. Considering the unit and all the mods needed, you are likely looking at $4000+. Your stock ECM/TCM would not support it in any way. I thought people only bought those as overdrive for e.g. their TH400 so that you could have overdrive. And then activated by a push-button on the dash. As least in the old day, perhaps there are aftermarket TCM that support it now (and cost another $1000).

Installing a 6 speed manual trans would be less expensive and you ECM likely can be tuned to support it. Assuming you want a manual trans.

At these prices, you find an engine swap to be the best solution. E.g. a 6.2l crate engine. If you just want better performance, bolt-ons can often give you a 25% boost in power; some bolt-ons will likely make you fail an emission test if you have them, but others should pass. Of course being in Michigan I know nutin about emission tests.

Rockrz

I wouldn't want to swap engines just to get a couple of extra gears in the automatic tranny (wouldn't want a manual at all)

Someone was telling me on another board that the 4L80 may fit physically in my truck and my ECM may support it with a re-program.

That would be great news if that worked out cause I'd like to have a couple of higher gears for better highway drivability and fuel efficiency like the full size pickups.

mrvedit

Yes, a 4L80E will fit, but it will give you worse gas mileage for several reasons.
1. Overdrive in a 4L80E is .75 versus .70 for a 4L60E. In other words with a 4L80E your engine will rev higher on the hwy and likely use more gas.
2. The 4L80E wastes about 5HP more than a 4L60E.
3. A 4L80E weighs about 50 lbs more than a 4L60E.

A 4L80E has tighter gear ratios which are desirable in a lighter weight car and the tighter ratios often make it faster on a drag strip despite the extra weight and 5HP loss.

GM had a strong incentive to make your truck as fuel efficient as possible. You are unlikely to improve on it without either spending mega bucks and/or flunking an emissions test.

BTW - Your truck might have a 4L70E or 4L75E trans; it doesn't matter 4L60E, 4L65E and 4L70E are all basically the same trans with the same case and gear ratios.

Rockrz

I was just looking at a print out the original owner gave me when I bought this truck at 6400 miles (I'm the second owner) and it says the transmission is an "M30 Automatic Transmission" but I don't know if that was the original equipment list printout before the original owner made some special order requests or not.

Yeah, I guess I should really consider the fact the GM knew what they were doing when they decided on the components of this truck.

I just hear about the newer ones coming with 6 speed automatics and thought since they are doing that now there may be some advantages.

Never hurts to open up a thread and see what the views of others are on a subject...

I'll just stick with my original plan of getting it tuned to tweak it that way a little and then drive it till I leave the planet!