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Newbies read this first before you post. And if you have a question, read this again. Not that I don’t like you or don’t like helping you but with hundreds of repeat threads on here, it burys the new questions. Thanks and enjoy.

This is in random order so bear with me.

First off when I and others say stock truck we mean stock engine stock turbo stock injectors, stock that. Programmers exhausts intakes, trannys and other little things are still part of what I consider a stock truck.

Does your duramax tick or knock?? It is normal to some extent. It can be fairly audible and on a fairly stock truck it will be normal, on a modded truck you will know that it sounds different and we can help you from there.

Here is a thread with all of the juicy details.Does Your Duramax Tick/Knock?? Read First.

Next on this list. If you are experiencing any of these symptoms on your LB7 yes your injectors could be bad.

Smoking at idle
Rough idle
Raw diesel smell
Poor MPG
Reduced power
Knocking sound.
Fuel in oil

If you suspect that your injectors are bad first perform a balance rate test. There are a couple of aftermarket canned tuners that do this. Canned tuners are tunes that are not custom so anything besides EFI Live or HP tuners. EFI live will also perform this test as will other scan tools and of course a Tech II.

To perform the test get it up to operating temperature then when at idle in park if any of the balance rates are +/- 4 then you have something going on in that cylinder. You can also do this in drive with the park brake on. If it is +/- 6 then you have something going on. And when you hit the throttle they will all go to 0 this is normal.

If you have a balance rate out of spec, it means either a compression loss or bad injectors. On a stock truck its usually injectors or possibly an unseated injector cup. Take it to the dealer and have a return rate test performed. They should know what to do. If it is on a modded truck (big turbo ETC) it could be and unseated injector cup, bent rod or cracked piston.

The injector service policy is just that, and injector service policy. Its not a warrenty therefore it does not follow typical warrenty procedures. Your injectors are covered for 7 years or 200,000 miles from the delivery date.

In order for your truck to qualify it must fail the return rate test, balance rates mean nothing. If you think the dealer is screwing you ask for a printout of the results. Then show them to us and we canhelp you.

If your truck qualifys, the dealer is to replace all 8 injectors at no cost to you, not even the $100 warrenty fee because it is not a warrenty.

Now many dealers are also retards and will either try to screw you or they are just dumb. If you think one dealer was wrong, get a few other opinions from other dealers.

Now if your truck is out of the limits for the special service policy you have three options.

1. Get raped by the dealer $4,000-$5,000
2. Have a reputable shop do them
3. Do them yourself, its really not that hard and Bosch Remans from Pensacola diesel are only $206.50 each. Make sure you use Bosch remans others have been failing.

So why do these injectors fail? Ball seat erosion or cracked bodies. The exact causes of the failure of these two areas are still up for debate.

What happens if you keep driving with bad injectors? Well if they are leaking fuel into the oil, you can cause premature wear or even failure of a lot of the bearings in your engine. So just don’t do it.

Does this happen on other engines, yes duh, injectors go bad. But nothing at the scale of the LB7s. Its uncommon on other models.

Now for you guys with a 5spd, which is everybody with a truck built prior to 2006, you cant do anything to your transmission except a full rebuild with a performance kit. A bully dog shift kit is junk and a transjo Jr wont do anything. A Full transgo will, but you have to disassemble a lot of the transmission, which by then you might as well do a full kit.

Now for the 6spd guys a transgo jr will help a little, but not a ton, still worth the price though. Bully dog kits are junk, stay away.

Will a deep pan help? Looks maybe, cooling NO. It just keeps the fluid colder longer, but once its warm its warm. But the mag hytec has cooling fins, still doesn’t do much of anything. And it becomes nearly the lowest point on the truck making loading it on a trailer a BITCH. If you want a cooler tranny buy a larger cooler.

What is limp mode? Limp mode is a protection mode for the Allison, basically when it senses slip it will default to 3rd gear and keep the converter unlocked. You can still back up go into nuetral and use park, but in drive 3rd 2nd and 1st you will be in 3rd no matter what. You will also get a CEL, you will most commonly get a P0700 and P0735. The 700 just means that the TCM requested a CEL, the 735 means 5th gear incorrect ratio or slip. Is this bad, yes. How do you fix it, turn your programmer down and quit beating on it or drop the coin on a performance kit.

Can you flush an Allison, yes and no. you cant flush it like a normal transmission but there is the hoot method of flushing it.

How often should you change your spin on 10-12,000 miles. And make sure you use good filters. NAPA, Allison and ATP I know are good filters. Good meaning the magnet does not block the holes in the filter. Make sure you remember to clean that magnet and reinstall it.

What fluid does your allison use? Dex III for 5spds and Dex VI for 6spds. Does Dex III work in 6spds, no. Does Dex VI work is 5spds kind of. The seals are not made for it, and overall Dex VI is not a very good fluid anyways, as it has been known to freeze in frigid temps.

Does your 5spd Allison not shift right and blink Range Shift inhibited? You may have a bad NSBU switch.

What fluid does your transfer case use? ATF. But doesn’t it use Auto Trac, no just ½ tons. Can you overfill it with 5w30, sure do whatever you want. ATF is what is supposed to be in there.

What is pump rub. it’s a hole wore in the rear housing from the pump in the T case. Why does this happen, because the pump only contacts in 2 places. How do you fix it? With a pump rub kit from Adapt-A-Case (cheap way) or Merchant automotoive (more expensive) both ways work. Is it hard to install, not really. Should you do it, absolutely.

Do you need a tranny temp gauge, no your factory temp gauge is the most accurate.

Are you scared you are overevving your truck? don’t be. Unless you Modified the tuning you wont be able to over rev it past the fueling limit. When coasting the truck may downshift and cause the RPMs to climb into the red, but the red really isn’t the red, coasting redline is 4500 or 4800 cant remember. The 06+ trucks have an updated tach that shows the new redline so people don’t get scared.

Is your truck running hot? No the coolant temp gauge lies but about 20* give or take 20* that’s how accurate it is.

Do your gauges randomly not work or flutter? Then yopuy have bad stepper motors GM covers these somewhat but good luck, if you are good with electronics you can replace them yourself or get a new gauge cluster from GM for a couple hundred bucks.

When should you use two/haul? Whenever you want. What does tow/haul do? Locks the torque converter in every gear above 1st and uses adaptive grade braking to slow you down.

Do you need tie rod sleeves? Absolutely. Where do youy get them? Any shop, they all have them, they are as common as oil filters these days. Why do you need these? Because Honda Civics have bigger tie rods, and yours will break eventually under high loads in 4x4.

Do you need a straight centerlink? Only if you are building a competition only vehicle, they suck for street use, you can strap your centerlink or buy braces for it for a street truck. Why do you need this? Because the stock one is curved on both ends and when under force in 4x4 it will twist and pull the tires in causing CV shaft breakage.

How do you change your fuel filter? Click on the link below. Do you need special tools, NO. Do you need the WIF sensor wrench, no. Ive changed tons of these and still don’t have one.

How To: Change The Fuel filter

Does your steering wheel fell loose and kind of knock when you are turning? Then you probably have a bad Intermediate steering shaft. These are $53 from parts zone online and don’t take long to put in.

What types of tuners are there for your truck? Tons. Boxes, Modules, Programmers, Downloaders, but no chips. Please refrain from that term or you will be harassed by other members. Chips go into the ECM, we don’t have that option.

What is EFI Live, custom tuning software. Is it hard to use, sort of. Does it take long to learn, yes. Will it break parts, if you want it to. Should you get it, up to you.

On an LB7 is the PPE boost valve worth the money, definitely. What is the max boost it will let you go to. 32-33psi sometimes with higher spikes on big tunes. Should you also install and Banks big head, no. One or the other. What is the max safe boost range on an LB7 turbo, about 30-33psi. Anything over is hard on it and is just hot air. What brand turbo is the LB7 turbo, IHI. Who are they? A big turbo company.

What turbo is on the other duramaxes, VVT Garretts. Are they all the same, no.

Do LLY trucks have injector issues, not usually. Why not? Different injector location, and different injectors. Are they still Bosch, yes. What issues do they have with injectors, the #2 and #7 injector wiring harnesses. What happens when these go bad? Your truck sounds like a power joke. Is it expensive to fix, no.

Do LBZ pistons crack? Yes at high power levels. Why do they crack, because they are cheap crappy pistons. Why don’t the LB7 and LLY pistons crack, because they are nicer MAHLE pistons.

Do you need bigger injectors, probably not. On an LB7 they will flow anything your stock motor can handle, other motors will benefit some, but up to you.

Does your radio swallow Cds? Don’t worry its common, buy a new radio and a new CD and away you go.

Where do you put the pyrometer probe? In the exhaust manifold. Where is the exhaust manifold? On the side of the motor, big rusty looking thing. Which side do you tap? Passenger side? Why that side, easiest to get at. Which side runs hottest, drivers side. Why not tap that one, Biotch to get at. O, okay. How do you tap it? Drill an 11/32” hole then tap with an 1/8” NPT tap checking for fitment along the way, don’t tap it all at once. What about those metal shavings. You have three options, one is hold a vacuum there to catch them, the other is to do it with the engine running (wear safety glasses). The last one is to just run them through the turbo, it doesn’t do much to it. Never put grease on the tap or drill bit, makes things worse. You can also magnetize the bits to catch the filings if you really have no friends and are bored.

Where do you tap the boost gauge. On LB7s in the wastegate line, how do you do that. Splice a T into it and connect your line to the T. Wht about if you have a Boost increase valve? Put the T before the valve. Where do you put it on other motors, on the EGR intake manifold bridge dealio. Remove it then drill it and tap it with the same procedure as the pyro.

Where do you tap for a power for your gauges? A keyed power source capable of running the gauges. I like to use the sunroof fuse. What do you tap it with, cheap fuse taps or a better way is to use TAPA-Fuse deals from NAPA or other stores, more pricey but the right way.

What about for a lighting source? Tap into the trailer lights. Why not the dimmer switch? Because they have been known to burn out due to the load.

When you try to put your truck into 4lo it just blinks and doesn’t go in? Read the owners manual, you have to put the trans in nuetral.

Is it safe to shift into 4hi while cruising down the road? Yes just don’t do it with your foot to the floor.

Does your truck jerk when you come to a stop? Check the driveshaft slip yoke. Try regreasing it otherwise install the updated yoke.

How do you grease your U-joints? You don’t they are greased for life (factory ones on most trucks).

Do you think your wheel bearing is out? If your truck is humming while going down the road one of the probably is. Lift it up and grab the top and bottom of the tire and try to rock them back and forth. If it has any movement it is bad. Can your just replace the bearing, unless you are superman, NO. You have to replace the whole hub, but that’s expensive, too bad.

Do you want a smoke tune? Too bad nobody will give you one. But smokes cool right? No its not, it has its place at the strip and the pulling track, but on the streets it is ruining our industry, and if you bring it up you will get flamed for it.

Will aftermarket modifications void your warrenty? Depends on the service writer? But what about the magnuson vs. moss act? Many loop holes, really only works for K&N filters which suck.

Do you need an aftermarket intake on your truck? No not with a stock turbo.

Can you delete the DPF, yes. Is it illegal, yes. Do you need a tuner to delete it, yes.

More later Im sick of typing.
That was a great write up i loved it, What do you you think of the recall to lower the temp on the DEF that when yo do it it lower your mpg by 5 mpg
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