4.56's are in!!!!

Jacoby · March 30, 2019

And theyre GREAT!!!! Best mod to date and worth every penny. Back ground on my truck. Its a 17 CC 1500 LT 5.3L 3.42 gears. Ive got a 7" lift and 35" M/Ts. I have an S&B intake, MBRP exhaust and custom Diablew tune. The truck ran well with all that but I do a lot of towing and needed the extra grunt so a gear swap was in order. After searching forums and looking over multiple calculators I decided on 4.56's. After driving it for a little bit I think I made the right decision. The truck just go's with little throttle input. It will hold 6th gear now with no issues where as before it would down shift on the smallest of inclines. Im having to baby it for 500 miles so I haven't towed with it yet but look forward to it and will post my impressions after I do. I suspect it will be a breeze and a much more enjoyable experience. Im having to work out a few kinks with calibrating my tuner for the new ratio. For some reason every time I get to the screen to adjust tire size and gear ratio it freezes up. I've got an email out to Lew and Diablo. I know the gear ratio can be changed in the tune file on their end so even if I have an issue with the unit itself I should be able to get that corrected so my speedo is more accurate. At the time being running 75mph verified with GPS my speedo says 93mph. I restored my factory tune and hoped maybe starting with a fresh install of my custom tune would work but it doesn't. I have to admit though now driving with the oem tune is a much more pleasant experience then before. I actually like the way it shifts better then before with my TCM tune from Lew. It was short shifting like crazy last night with the Lew tune and my guess is just because the ecm didnt recognize the new ratio. Driving around on hwy and backstreets it will stay in V4 mode a lot longer than it did when I got the truck. The slightest throttle input would kick it into V8 but now you have to give it quite a bit more throttle to make it go to v8. That's good news for the folks that want to keep the AFM on. Once I get the tune fixed I'll be turning mine back off. Gas mileage is already going way up. While running 75mph (93mph on speedo) I was hovering right around 18mpg according to the gauge thing with the blue bar that moves. That's pretty damn good especially when the ECU thinks Im really going 93mph. Before the gears I was lucky if I could get 15mpg going down hill with the wind at my back. I know some guys were curious about rpms and what not. Running 70mph im right at 2000rpm and 75mph puts me right at 2200rpm. For you guys that already have a droney exhaust you may not like that high of an rpm. With my exhaust I don't mind it at all. I like being up in those higher cruising rpms though because throttle input is minimal and the power just comes on. That's all I can think of for now. I'll update when I get the tuning fixed and reach my 500 mile mark. Then I'll be able to get out there and give er hell and see what the real improvements are.

So as of now its nothing but positives. As I said just a couple of tuning kinks to work out but nothing big.

flyingfool · March 30, 2019

can't read your post without some breaks in the paragraph and commas.. i can filter out bad spelling but this gets tiring to read on our forums, these days it seems everyone needs a remedial English class.

next upgrade... forged axles , snap snap...

Edited March 30, 2019 by flyingfool

kennerz · March 30, 2019

I had a similar problem with my diablew tune when I tried to make a modification for tire size. It's not lew's tune it's the order you call up the custom tune/modify tune screen. You have to load the custom tune selection, then go into modify tune. I was going straight to modify tune since the tune was already loaded. Doesn't work like that. You can change the gear ratio in his custom tune yourself.

Thanks for sharing on the gear update, I would think anyone with larger/heavier tires would be interested.

Edited March 30, 2019 by kennerz

SierraHD17 · March 30, 2019

I try and tell guys this but they never listen lol. I run smaller tires (34") and wouldn't trade my 4.56s for anything. Actually helped with my exhaust as it was annoying at that 1700 rpm mark and quiets right out above 2000 rpm where it is now. Even if I dropped back to stock tires on my truck I wouldn't change gearing.

Jacoby · March 30, 2019

1 hour ago, flyingfool said:

can't read your post without some breaks in the paragraph and commas.. i can filter out bad spelling but this gets tiring to read on our forums, these days it seems everyone needs a remedial English class.

next upgrade... forged axles , snap snap...

Go eat a dick

1 hour ago, kennerz said:

I had a similar problem with my diablew tune when I tried to make a modification for tire size. It's not lew's tune it's the order you call up the custom tune/modify tune screen. You have to load the custom tune selection, then go into modify tune. I was going straight to modify tune since the tune was already loaded. Doesn't work like that. You can change the gear ratio in his custom tune yourself.

Thanks for sharing on the gear update, I would think anyone with larger/heavier tires would be interested.

That makes sense. Since I’m on my oem tune now I’ll try this when I get back home. So modify my custom tune before I load it instead of modifying it after it’s loaded. Thanks for the tip

Jacoby · March 30, 2019

2 hours ago, kennerz said:

I had a similar problem with my diablew tune when I tried to make a modification for tire size. It's not lew's tune it's the order you call up the custom tune/modify tune screen. You have to load the custom tune selection, then go into modify tune. I was going straight to modify tune since the tune was already loaded. Doesn't work like that. You can change the gear ratio in his custom tune yourself.

Thanks for sharing on the gear update, I would think anyone with larger/heavier tires would be interested.

That worked!!! Thanks for the tip. I was able to go in and modify gear ratio and tire size prior to uploading the custom tune. Now Im only off 1-2 mph on the speedo compared to gps. So nice when someone actually helps work the problem instead of offering up a grammar lesson

kennerz · March 30, 2019

Glad I could help. Once you get the ratio and the tire size correct and it re=learns after a tank of gas or so you will notice a huge difference and the power will come back. My computer seems to take about two to three tanks of gas before I get normal mileage and all the power after I flash it (AF ratio settles in)..

Your truck should drive real nice compared to how it was. OEM tune is very lacking.

Jacoby · March 30, 2019

1 hour ago, kennerz said:

Glad I could help. Once you get the ratio and the tire size correct and it re=learns after a tank of gas or so you will notice a huge difference and the power will come back. My computer seems to take about two to three tanks of gas before I get normal mileage and all the power after I flash it (AF ratio settles in)..

Your truck should drive real nice compared to how it was. OEM tune is very lacking.

Yeah it’s all weird now. Running Lews tune with no gears to running oem tune with gears now back to Lews tune with gears. I’ll give everything a few days to settle in

tyler.frost92 · April 2, 2019

On 3/30/2019 at 2:04 PM, Jacoby said:

Go eat a dick

That makes sense. Since I’m on my oem tune now I’ll try this when I get back home. So modify my custom tune before I load it instead of modifying it after it’s loaded. Thanks for the tip

lmao, im pretty sure thats the same guy that made a post about always running into peoples vehicles in parking lots. Who is he to judge?