Is converting to manual possible?

Joanna · August 14

I am wondering if it’s possible to convert the 14 gmc to a manual transmission? My truck has 150,000 miles currently. And my transmission is acting up again. This will be the 5 th transmission in this truck. 6L80E is the biggest piece of junk ever made.

CamGTP · August 14

Not knowing the history on who is putting in these transmissions and how you drive the truck, some of this could be self inflicted. Like if you put in used transmission or you had a "shop" do rebuilds for you. Always use a GM transmissions or buy a built transmission from a company with skin in the game. Also never run the stock 6L80e converter again, get a billet torque converter that won't break like the stock units do.

And to answer the manual question. Sure, anything is possible but good luck making it work. You can convert it to manual but you're going to spend way more money, way more time and you better know what you are doing. These trucks never came with a manual, so nothing exists as far as swap in and go parts. You'd be piecing it all together from various manual transmissions from cars. Then you have to figure out how to make the truck happy now that it doesn't have an automatic transmission anymore. Can't really just tune it when that combo never existed, so you can't just change the calibration file to make it work.

Grumpy Bear · August 14

7 hours ago, CamGTP said:

Not knowing the history on who is putting in these transmissions and how you drive the truck, some of this could be self inflicted. Like if you put in used transmission or you had a "shop" do rebuilds for you. Always use a GM transmissions or buy a built transmission from a company with skin in the game. Also never run the stock 6L80e converter again, get a billet torque converter that won't break like the stock units do.

And to answer the manual question. Sure, anything is possible but good luck making it work. You can convert it to manual but you're going to spend way more money, way more time and you better know what you are doing. These trucks never came with a manual, so nothing exists as far as swap in and go parts. You'd be piecing it all together from various manual transmissions from cars. Then you have to figure out how to make the truck happy now that it doesn't have an automatic transmission anymore. Can't really just tune it when that combo never existed, so you can't just change the calibration file to make it work.

Was not the manual transmission an option in Mexico in early K2's?

KARNUT · August 14

Yes it’s possible. But you have to either be ok with high labor costs to have someone else do it. Or do it yourself. As far as the automatic transmission problems. There’s rebuilders out there that warranty their work. With the amount of problems stated with the miles presented. Indicates to be the problem is with the process not the product.

Grumpy Bear · August 14

5 hours ago, KARNUT said:

Yes it’s possible. But you have to either be ok with high labor costs to have someone else do it. Or do it yourself. As far as the automatic transmission problems. There’s rebuilders out there that warranty their work. With the amount of problems stated with the miles presented. Indicates to be the problem is with the process not the product.

I had a TH700-R that would fail about twice a year for two years running. Dealership rebuilds. I found a guy who drag raced a roadster that used one. I let him rebuild it. BINGO. Ran to the grave with that build a decade later and over 300K on the vehicle. Agreed. Not always the parts.

CamGTP · August 14

If a K2 truck did, it was probably a 4.3 truck and not a V8 truck but that would need research.

A US calibration file likely still doesn't exist and if it's for a 4.3 and not a V8, it still wouldn't work. I'm sure there are work arounds like using a Camaro operating system but then other things in the truck won't jive with a car OS and things like that.

Joanna · August 19

On 8/14/2024 at 12:02 AM, CamGTP said:

Not knowing the history on who is putting in these transmissions and how you drive the truck, some of this could be self inflicted. Like if you put in used transmission or you had a "shop" do rebuilds for you. Always use a GM transmissions or buy a built transmission from a company with skin in the game. Also never run the stock 6L80e converter again, get a billet torque converter that won't break like the stock units do.

And to answer the manual question. Sure, anything is possible but good luck making it work. You can convert it to manual but you're going to spend way more money, way more time and you better know what you are doing. These trucks never came with a manual, so nothing exists as far as swap in and go parts. You'd be piecing it all together from various manual transmissions from cars. Then you have to figure out how to make the truck happy now that it doesn't have an automatic transmission anymore. Can't really just tune it when that combo never existed, so you can't just change the calibration file to make it work.

The truck I bought used from a Chevy dealership, they informed me the transmission had been replaced, well 3 months later I had to pay a transmission shop to rebuild it. With a new converter. 7 months later it went out again. I bought a new transmission with converter. It’s lasted about 30,000 miles. I was informed the torque converter is only guaranteed for 12,000 miles or 12 months. So if it fails after warranty. Then the transmission is not covered. Due to failure being torque converter. So it’s a catch 22 to say.

but to convert I understand it’s going to be some what of a challenge. If the ecu and Bcm can not be reprogrammed. Then a stand alone fuel system would need to be installed, and gauge clusters would need to changed along with redoing the wiring to control the modules on the bcm. Fabrication of the clutch pedal and a shifter would be the easiest part. Just need to find a manual that will allow the transfer case to bolt too. Or do I need to find a divorce transfer case. I am aware of the work I have restored many of vehicles. And have degrees in mechanics and metal fabrication, and other processes too. And also a lab assistant in the automotive courses at a college I work at.

CamGTP · August 19

If possible when getting a rebuilt transmission, always use an aftermarket converter with a billet parts, that way it can't fail again.

And yeah, to my knowledge there is no operating system for a truck with a V8 manual in a K2 truck. I have yet to see a build and never seen anyone on the HP Tuner forums get a file that exists for a swap like that. I still think it's possible with a Camaro operating system but again some things will not function anymore in the truck because the PCM/BCM and ABS systems would be able to talk with each correctly anymore.

I know for sure you can run a Holley System to control the engine and have a new dash with that. But making the auto 4X4 and brake stuff work is going to be a task and might not even be possible.

Edited August 20 by CamGTP

Joanna · August 22

On 8/19/2024 at 6:51 PM, CamGTP said:

If possible when getting a rebuilt transmission, always use an aftermarket converter with a billet parts, that way it can't fail again.

And yeah, to my knowledge there is no operating system for a truck with a V8 manual in a K2 truck. I have yet to see a build and never seen anyone on the HP Tuner forums get a file that exists for a swap like that. I still think it's possible with a Camaro operating system but again some things will not function anymore in the truck because the PCM/BCM and ABS systems would be able to talk with each correctly anymore.

I know for sure you can run a Holley System to control the engine and have a new dash with that. But making the auto 4X4 and brake stuff work is going to be a task and might not even be possible.

Getting the fuel system to run the engine isn’t that big of an issue. ABS not that big of a concern really either, if there isn’t away to get abs to work no big deal. Transfer case can be possible put on a separate electrical system. Not having auto 4x4 is no big deal. I have never ever used auto 4x4. I switch it when I need it. And if the transfer case won’t work. It’s no big deal to install a manual transfer case. The only concern is which manual transmission will fit what transfer cases. It’s also possible I can make a lot of the systems to work with a donor wiring harness and pcm and bcm.

MikeBMW · August 22

You want a manual? Just put it in tow mode and run up and down the gears of the butons on the shifter?
I, mean, unless you're really into three pedal driving, go for it! I'd like to see more!

Edited August 23 by MikeBMW

Joanna · August 23

On 8/22/2024 at 12:12 AM, MikeBMW said:

You want a manual? Just put it in tow mode and run up and down the gears of the butons on the shifter?
I, mean, unless you're really into three pedal driving, go for it! I'd like to see more!

I love 3 pedals. Drove a semi for a few decades. But my main reasons in changing to a manual, is the constant transmission failures in this truck. To replace it again will the 5th transmission so far with a 150,000 miles. The last transmission lasted about 28,000 miles, the one before it was less than 10,000 and the shop would not stand behind their work. And since I don’t know when it was replaced before I bought the truck. All I know is the dealer said the transmission was replaced before. But the transmission went out 3 months of me owning the truck and the dealer wanted 8000.00 to fix it. So I had it rebuild at a local shop which did not last, for 3400.00. So no I am not a fan of automatic.

Homewrecker007 · August 24

4 hours ago, Joanna said:

I love 3 pedals. Drove a semi for a few decades. But my main reasons in changing to a manual, is the constant transmission failures in this truck. To replace it again will the 5th transmission so far with a 150,000 miles. The last transmission lasted about 28,000 miles, the one before it was less than 10,000 and the shop would not stand behind their work. And since I don’t know when it was replaced before I bought the truck. All I know is the dealer said the transmission was replaced before. But the transmission went out 3 months of me owning the truck and the dealer wanted 8000.00 to fix it. So I had it rebuild at a local shop which did not last, for 3400.00. So no I am not a fan of automatic.

The shift lever might have a few zig zags in it to come out in the right place.