Bill Reinhardt

Can't drive too fast where I live, it's also pretty flat. Seems like the 2.7L is a good fit, now do I wait for the 2022 refresh?

Thanks for the insight! Yea I figured I cant go wrong with either for what I need. The 2.7L certainly intrigues me with being a newer design. Glad to hear that you have no lag or delay when shifting.

Got a few questions for those with the 2.7L, hopefully you guys can help me out. I'm interested in the 2021 Elevation models. Having a hard time deciding between the 5.3 and the 2.7 for my use. For how I use a truck, payload is key. It will be my primary means of transport as well (75% city/25% highway). With that said, it seems like the 2.7L is right up my alley as the payload is north of 1800 lbs and gets the best city mileage of the lineup. However, it seems like there are comments of turbo or transmission lag when passing on the highway. Wondering if these comments are justified? From some of the video reviews I've seen, the reviewer will give it some juice to represent a pass, the engine will rev up, then the reviewer will count 1 or 2 seconds until the truck actually spools/shifts, then finally accelerates. Does not appear to have that issue from a stop. If anyone could share their experience, that'd be appreciated. If the lag is real, it would probably annoy the hell out of me. I also have to ask if the issue goes away with the 5.3L, or if it's an 8-speed problem (or both). My local dealerships are getting a few more trucks in over the coming weeks that I can go and drive to find out for myself, but just wondering what the tribal knowledge is on this topic before hand.

Ever get this resolved?

You are correct, much more goes on than just that! However, we are trying to figure out if the OP's truck is tuned and if so, by what. The Diablo tunes do this, it's a measurable trait that the OP can go and test to rule out a Diablo tune. These are also relatively cheap tunes, so I'm not surprised. Email from Diablew attached below. I don't think OP bought a truck tuned with a Diablo tune because not only would the transmission have a particular and unique shift behavior, but also the speedometer does not seem to be calibrated for the tires (which is just as easy to adjust as disabling V4 with the Diablo. The options are right next to each other). It's entirely possible that the previous owner bought a used Diablo, disabled V4, then sold the unit or did not do anything else with it. Unlikely as there are far simpler and cheaper methods to only disable this one feature and not apply a tune.

Anything plugged into the OBDII port underneath the steering wheel? I think they sell V4 deletes that sit in there... Unlikely, but throwing it out there

14 mpg is normal for short commutes in cold weather on average. V4 may not engage unless certain conditions are met, such as engine/transmission fluid temperatures. I noticed you said you have a short commute, as do I. Before I got a tune, mine would not engage unless I drive it for a while and only when everything is up to operating temperatures... took 10-15 minutes of driving at least just to hit those temperatures. With a 7 mile commute, V4 never turned on for me, even on the highway. Have you tried a long highway run at normal operating temps? Light throttle at 60 mph for as long as possible? Also, I'd still suggest finding out the minimum speed from 1->2 to rule out Diablo/Lew tuning: I have an email from Lew stating that all the Diablew tunes do to increase shift points is to bump up the upshift points by 2 mph, the canned tunes bump it up by 4 or more. Stock 1->2 is at 12mph, Diablew 1->2 is at 14mph, canned is at around 16mph. Obviously there is more going on to change the shift quality and speed, however, the truck will REFUSE to shift any earlier than 14-16 mph if the TCM is tuned with a Diablo tuner, even downhill, no matter the temperature or circumstances. Your digital cluster should have a digital speedometer option to help identify the speed. If V4 refuses to come on at normal operating temperatures on the highway and your shift points are set by mph, its most likely a Diablo tune.

Shifts from 1st to 2nd at around 2500 rpm? Sounds like the canned Diablo firm shift tune. Stock transmission tune on my truck shifted from 1st to 2nd at 12mph (~2k rpm), but the diablo TCM tune shifted at around 17 mph (~2500rpm). The other gears shifted a little later, but on the 1->2 was noticeably different. You can test this by driving very slowly with minimal pedal input. Record the absolute earliest speed that the truck shifts from 1->2. The custom tunes will calibrate shift points by speed rather than RPM I'm assuming you have the 6 speed with a 5.3L?

That's great! All the way up past 80mph? Also, how much does a dealership charge for a driveshaft rebalance? Or was it covered under warranty?

So what do you think it was? Driveshaft or tires? Also, what specifically did they do to your driveshaft? Balance? New from factory?

I got a new TCM tune from Diablew that has nearly eliminated the engine brake feel during downshifts as the truck comes to a stop. So with the Diablo tuner and a custom tune, it can be fixed. I'd assume the same with Blackbear. However, the occasional driveline "clunk" is still present. I think this is more of a driveline slack problem rather than a transmission problem. Worn parts are most likely the culprit for me.

I changed the verbiage in my original statement to say a "less aggressive engine brake" as I felt that there was nothing soft about it, lol

There are a few comments suggesting a TCM tune. With the problem as you describe it, I'd like to point out that a tune, for me at least, exasperated the downshift problem as-described. To me, it feels like a less aggressive "engine brake" that cannot be disabled. The TCM tune I received from Diablew, while great on the upshifts and around-town driving, did NOT help with the downshift feel while braking. Since the shift pressure was increased, it only increased the feel of the downshifts. I will contact Lew and see if there is something that can be done to change that, but with how many of these trucks he has tuned, I'm surprised it's not a part of the default package.

Tuning it out is good enough

Work truck, as vanilla as it gets 2014 5.3L 4x4 w/ 50,000 mi