The 5.29 Mega Thread!!

4hi must be engaged for the front ring and pinion to turn. Track 4wd mileage for correct break in.

 

What is an acceptable max speed when breaking the front?

I am sure that I will have to treat the front, exactly as I did the rear in regard to heat cycling and keeping my speeds varied.

Just wanted to ask those who run their trucks at speed in 4wd.

 

Can be engaged at speeds 50mph and below. Can drive as fast as you want, or the truck can go in 4hi. I believe the break in procedure says not to go over 55mph during break in for both front and rear.

 

55. interesting. There is no speed limitation on ECGS's break in procedure. i still kept it under 55 during the first 3 cycles but have since been to 65 on some short cycles since i saw no speed limitation posted on their procedure. I'm goin to stick to 65 and under from here on out tho.

 

I think I read that 55 in another break in, maybe nitro or yukon.

 

I drive lots of highway so I hope 65ish is ok because I don’t want to be driving everywhere at 55 for 500 miles.

 

MY SHOP (Mule) limit is 60 mph, for the first 100 miles.

Actual Nitro statement:

"
BREAK-IN PROCEDURE:
In order to prevent damage to differential components it is essential to follow the break-in procedure after installation of a new ring & pinion. New ring & pinions will generate more heat initially after installation and can cause gear oil to break down, leading to premature failure. On your first drive, stop after the first 15 or 20 miles and let the differential cool for 20-25 minutes before proceeding. Drive conservatively for the first 500 miles following installation (avoid hard acceleration & towing). After completing standard break-in, tow for very short distances (less than 15 miles) and let the differential cool before continuing during the first 45 towing miles. Change the gear oil after the first 500 miles. This will remove any metal particles or phosphorus coating that has come from the new ring & pinion.
Premature overloading/overheating will cause gear oil to breakdown, and may result in parts failure."

 

Got about 75 miles in on break in. I’d say my situation has been ideal for break in so far. A bunch of short 5-10 min drives where diffs have fully cooled and maybe two 20 min drives thrown in there. You can definitely hear the gears, nothing too loud or really concerning. Not sure if they’re getting louder or it’s just me listening closer to them lol. Do they quiet down or stay about the same?

 

Hear the gears? Hope it’s not because they were setup incorrectly. Follow up once you get some more miles on them as I’d like to know if they quiet down or get louder.

 

will do. I’ve read a lot of others talking about it, and videos as well and expected it. I feel like I’m listening for it. Once the tires get rolling they over power it but nothing a little music can’t drown out. it’s just a faint ,rolling ,bearing type sound Not very loud but definitely noticeable.

 

I can definitely hear my gears as well. It's not that bad until decel coming off the highway when the gears unload. The installer says it's typical for people like me running stock tires w/5.29's and will almost entirely go away with larger tires. I'm suspicious on how that makes a difference, but we'll see.

 

I've noticed that all of the 8.75" diffs I've regeared, putting the pinion depth shims behind the race has resulted in noisy gears and placing the pinion depth shims between the pinion head and bearing has resulted in zero to very minimal noise.

 

nice! great observation. is that your go to assembly now on the 8.75"?

 

Hmm, good info.

Now to figure out how to suggest this advice to my installer without sounding like one of those guys that says, "Well the internet said this!" haha

Does this in any way effect the performance or durability of the gears long term, or is it just noise that is the negative side-effect of this?

 

Yep - here is the way. Surely any mechanic will ignore you, regardless. And often do the opposite. Don't tell him to place the pinion depth shims between the pinion head and bearing.....tell him behind the bearing......... He'll walk off mumbling...........OK I kid I kid.........just level with the guy and tell him what you want.

 

It doesnt really have an effect long term. 3rd gens have a wierd resonance. I've been using between .81 and .85 shim to get good depth. If using a solid spacer, you may not be able to put the shimming on the pinion head.

 

About 400 miles into my break in. One thing I’ve noticed is how many people I’m pissing off out here on the interstate. If you’re getting middle fingers, flashing highbeams and tailgaters. You’re breaking them in properly! Lol.

So far, 400 miles in 4wd I’ve netted an overall average of about 18mpg. This is about a 60/40 highway city mix but as I said I’ve been really babying it and going about 50-55 out on the interstate.

100 more miles to go then I’ll flush the oils and start pushing up my highway speeds to normal driving.

I think a lot of the gear noise I thought I was hearing and posted about earlier is actually road noise from my tires. I was mistaken on that. I think I have started to now correctly identify some very faint gear noise. Mostly noticed on deceleration at 55 down a highway grade engine braking. Just a faint whir that I think is coming from the front gears.

 

Drained both diffs last night after hitting the 500 mile mark on both front and rear. No big chunks just tons of shavings which is a good sign. New oil in and will prolly do another flush next oil change just to be safe.

here’s the front plug with tons of shavings which was the worse of the two. The front holds a lot less oil so the shavings were more concentrated. At first when I saw this plug I thought those were solid chunks of metal but after clearing them just tons and tons of ultra fine shavings.
what do you guys think? Think this amount of shavings is normal or of any concern?

now time to push the gears. So far I’m really enjoying them and feel I made the correct choice over 4.88’s. Time will tell after I spend more time at freeway speeds but so far, I’m happy!

 

I’m no expert but it looks like a small amount of polishing dust. I would say the break in was successful. Everything is mating perfectly and all the burrs etc are polished out.