The 5.29 Mega Thread!!

I think it’s 35mm. I’m pretty sure the last time I messed with the front diff, me not having a 35mm is why I didn’t disconnect the front CV from the bearing. Lol. I definitely had enough movement from the lower 2 knuckle bolts to make room for the CV to clear the diff though.

 

Assuming you disconnected the tie rod end and the sway bar?

I'm gonna yeet that dang cat shield. I don't live in a high crime area.

 

Sway bar only, for knuckle movement. The tie rod was fine to stay as is.

Yeah, I used to have a MillerCat. Crime appears to have died down, so I got rid of it. It made manual trans fluid changes a total pain. I haven’t missed it, though I’m sure now someone will steal my cat and change my mind, lol.

 

I don’t think I like the OTT tune with the 5.29’s. When I pull my boat anything between 60 and 70 mph sucks. Truck just can’t find the right gear and searches with high rpm’s. Before the tune 65 and 70 mph wasn’t a problem. Probably gonna delete the OTT tune.

 

What gear are you using?

 

Thanks for the tip, got them out (after a lot of banging). The driver's side is a bit in the way, but I think I can strap it up to get a little more room. Passenger side is plenty out of the way. Wiring disconnected and breather bracket is off, so all that remains is getting the cat shield out of the way so I can disconnect the driveshaft. My incorrect 36mm axle nut socket that I don't need arrived, but it looks like my security bits may be delayed until tomorrow.

 

I can send you my VIN locked file to have your tuner flash it. Compare and I think you’ll enjoy what I’ve got much better.

 

Front gears are in, everything works! Thanks for the videos @ClassyTacos. You were right, getting that breather tube back on the front is the worst part of it. Well, maybe behind just getting the diff back in, and about equal to using that hand pump to fill it with gear oil. Surprised the heck out of me when I actually got it on.

Tip if you do this yourself, keep the 2 front diff mounting bolts loose, and you can remove the driver's side bolt completely and let the diff hang forward a bit. It's easier to get your hand and arm up in there.

 

FIFY

 

I'm not entirely sure what you're trying to say here, are you saying the regear has thrown your speedo off? Because it wont affect your speedo.

 

It's the tire size that makes the speedo off. What size tires are you running? AT or MT?

I threw together a spreadsheet to calculate RPM at certain speeds in each gear (Freedom Units). The "615" is rotations per mile for current tire size, which I am running 285/75R16. Based on real-world measurements, it's pretty spot-on. I just did a brief highway run at 70 and it was right at 2200 RPM.

 

It affects the speedo on some 2nd gens. This thread is in the 3rd gen section so not 100% relevant to him…

 

Good catch. Yeah, I guess they used to get the speed from the tranny, so both tire size and gearing would affect the speedo.

 

I’m running 5.29 gears and the OTT with zero issues. Might need reflashed.

 

I can’t speak to the particular details, but I want to say the automatics actually do just run off of wheel speed, so speedo should not be affected there. He probably just has larger tires that are not calibrated for which are affecting the comparison.

I think only the manual transmission 2nd gens run off of a speedo gear measuring driveshaft speed.

Also, if it were from the gears, then his reading would be higher than actual, not lower. But hard to say without more info about the truck.

 

I second this. OTT with my 5.29s is amazing on 33s.

 

I'm finding the stock tune perfectly adequate with the 5.29's. I drive like an old man. I kinda am an old man. Anyway, I'm not seeing any reason to change the tune personally, the gear ratios were the biggest problem. But I could see that if you are already tuned for stock gears, you'd probably want to get an update that takes the new gearing into account.

 

Mine felt as if it drove fine before the 5.29 tune, although I never did get up to freeway speeds to know if there was a limit at 83mph. But I can say I saw a couple mpgs better after the tune. Not sure if it was because of the tune or just coincidental timing. It does feel smoother now though.

I asked what the differences were between the OTT regular tunes and the 5.29 tunes, this is what I got;

"There are shift schedule changes specific to the gearset you've installed, revised speed limiter settings and other small changes."

 

Yeah, I'm not sure I would even want to ever go more than 83mph in this brick anyway, lol. I don't think the ECM takes MPH into account, but I could be wrong. It's more about RPM, TPS, and calculated load that determines when it will actually shift. Anyone that wants to chime in with real details that doesn't want to sell me a tune, I'd be happy to listen to, but I haven't seen a clear explanation of how the stock system works and how a "tune" makes a huge difference.

The limitations seem to mainly be physical -- with stock gearing and tire size, the stock tune is a bit crappy and results in gear hunting due to crossing the load calculation threshold too often, but it's right on the edge. A tune can help with this. But start changing leverage ratios (bigger tires) and adding weight, no amount of tune will overcome that. There are physical limitations of available power vs leverage. You can change available power through supercharging, or change leverage through gearing.

Anyway, just did another few runs and the stock tune behaves great. For me, 5.29's was the answer I needed. The ECM doesn't know I changed the gearing, it's looking at other inputs.