chalou88

Hey guys, hope this is posted in the right area since it's regarding about three different things.

Just did a 209/217 .550/.550 112lsa cam swap in an lm7 5.3 half ton 2wd truck and a 4.11 gear swap with new bearings at the same time.

The guy who was going to do the tune said to fire the truck up, if it's drivable then bring it out (about 15 miles away) -- So I did and it runs good and is totally drivable on the stock tune. Idle is rough once it's warmed up but thats it. No codes or anything either.

The directions on the rear end gears said three 10 mile trips with 30 minute cool downs and that was it. Well i just called the manufacturer and they said wait 500 miles before any wide open passes.

So now it's short notice but I dont wanna take any chances on my new rear end. My question is, is a base tune really necessary given the truck seems to run fine, and also not going to hammer on it. In other words is it safe to do the 500 miles on the stock tune to break in the rear end and then wait for a dyno tune? Or should I still go out tomorrow and get a base tune? Just not educated enough on tuning and pcms and what not. Kind of my understanding at the moment that a base tune is required in more radical cam swaps just to get the vehicle to run and idle and what not to get out to the dyno but I kind of screwed myself by doing the cam and gears at the same time.

G Atsma

If I were you I would do the base tune, if only to be sure things will be closer to where they should be. Then you can break in the gears safe in the knowledge the engine is tuned better than originally.

chalou88

Thanks G Atsma for the good advice as always. Waiting to hear from my tuner, local guy with a solid reputation but hard to get a hold of. I wish Motive was a little more specific on break in instructions but at least im not a day late. Just dont wanna take any chances

00pooterSS

iTrader: (40)

I've never broken in gears 10 miles at a time. I just was easy on them for a bit.

The last set I had done up lasted about 10 miles before I hammered the **** out of it. But the car had street tires that broke loose with ease so it wasn't real hard on the gears. I wasn't very nice to it after that either and they were fine.

I'd drive it the 15 miles to the tuner. Let it set a bit. Then go tune it. Then let it sit a bit. Drive it home. Let it cool. Then plan to do some cruising over the next week then let it eat.

The base tune is more important than the super soft gear break in in my opinion.

Just be nice to it is really the main thing here. But the base tune being far enough off could cause some serious engine issues, so I'd make the base tune a big priority.

gagliano7

I wonder if that break in goes for new cars and trucks also? When i bought my 2018 sierra 6.2 within the first 10 miles i was beating the snot out of it. Every new car i ever had gets floored and redlined right off the bat. Never had a problem. I had an engine guy tell me if it is going to break its gonna break whether you take it easy or beat the snot out of it.

chalou88

Thanks guys, i drove it out and got a base tune last night. It seems to run really good. We are gonna put it on the dyno after i get some more miles in. I feel that if i follow the manufacturers instructions and then something happens at least i cant blame myself.

00pooterSS

iTrader: (40)

Let us know what it puts down, I'm curious how that cam does. Truck should rip with the cam and gears.

00pooterSS

iTrader: (40)

Oh and in the future, a LM7 is a gen 3 and this is the gen 5 section. No big deal just an FYI. Also the gen 3 section moves faster so if you want quick info the gen 3 section is usually where you'll get it.

G Atsma

I KNEW there was something off key about this.... lol

chalou88

Oh damn good to know, thanks. And i will definitely let you guys know what i get for numbers.

LilJayV10

iTrader: (39)

drive it to the tuner. let it cool down. strap it down and send it.