The 5.29 Mega Thread!!

What brand gears did you use? Go to their website for very specific break in instructions.

 

Are they warrantying the parts or the labor? If they aren't warrantying the parts then I would follow the manufacturer's recommendations. If they are warrantying the parts then maybe they know better. But I probably wouldn't take that bet.

 

Honestly lots of old school guys don’t preach the break in period as much. My guy has been working on diffs for over 50 years (maybe 60) and said if it was more of a personal decision than a must. I did mine anyways and gear oil was literally perfect.

 

My shop told me I didn't need to. Their logic was that the factory gears don't get their oil changed till 30k miles in, so why do it to your aftermarket gears?

I did it anyways.

 

Nitro 5.29 gears...I’ve called their shop & of coarse they highly recommend doing so. I’m most likely going to...just so I know I got the bit of metal shavings out from the break in

 

The shop I had do the job is a very reputable shop & the tech is very well known for his work so I do take his word for it. But in my own head I’d sleep better knowing that it’s fresh clean oil in there with the shavings out from the break in.

 

What rpms are you around going 75-80 with this wheel tire combo?

 

The break in period is really for heat. During that time your gears are grinding against each other and wearing off any imperfections in the manufacturing process which causes heat spikes in the oil. This is why you typically have 3 heat cycles after installation.

The gear oil is changed at around 500 because it’s been significantly degraded from heat and to remove the items that were ground off.

 

Why'd ya go and put science behind the break in period?

All jokes aside, you are dead right on this.

It would be nice if this logic was mentioned at the same time that the break in procedure is given to the customer to follow.

 

I've got the same tires and took a bunch of pictures of my gauge cluster on my commute yesterday. Take my RPM readings with a grain of salt because it's pretty hard to discern actual RPMs based off the gauge. I've attached images of the key speeds though.





I don't usually commute in my truck but I have twice this week for gear break-in miles. I'm averaging over 17 mpg on this tank, which is about 2 mpg better than I was getting before doing the gears. Granted, I'm driving like a granny, but staying out of 3rd gear on the hills seems to be helping a ton too. This truck really likes to cruise in the 60-64 mph indicated range which is fine for where I live.

 

@tacomarin thanks I appreciate it! Out in Cali everyone drives 75-80, so I’m trying to get an idea.

 

Lies! I'm in NorCal. But north of SF people don't tend to drive very fast.

 

Question. I’m getting nitro 5:29s installed right now. My shop said I have to do the 500 and change only the rear dif oil. They said I don’t have to break in 4wd. Is this true? I’m going to Potts mountain Jeep trail right after I change gear oil should I be breaking in 4wd?

 

Front is same as rear, you should absolutely break it in.

 

The shop that did mine told me to run in 4wd for 15/20 minutes and then let cool for 30 minutes three times just like with the rears.

 

Hi all, I didn't take the time to read the whole post but did read pretty far in to find that it is mostly a mod for big tires and off roading. Has anybody posted anything on towing with 529’s? I use my truck to work out of primarily. Tools as well as hauling fire wood, etc. I don’t have a full size truck because I am not climbing in and out of it to gather anything that I am loading or unloading. I do tow a travel trailer loaded to 6k a dozen times per year around the Appalachian mountains and am currently doing it with stock gearing and an AT, tires are 265/70/17. (Please don’t roast me, my mind is made up) It handles it well at 4K-4500 on 65-70 mph in third gear Appalachian highway hills. Same revs at 45-50mph in second on the two lane back road hills. These are not pedal to the metal, I manually shift and basically drive it in auto stick mode. I cruise up to speed from a stop, not just floor it and hope for the best. My issue comes when I am forced to lose momentum with traffic. Are 5.29 gears the answer or would the 4.88’s be better?

 

5:29s imo

 

I’ve read & seen different options/opinions for the differential oil after the 500m break in. 80w-140, 85w-140 etc...is there a specific reason for either? I’ll be hitting my 500m mark this week. So I need to flush mine out this coming weekend.

 

W stands for winter so the oils you mentioned are the same viscosity when at operating temperature. The only difference is when cold, and it’s likely a typo anyway.

 

I'm re-gearing to 5.29 specifically to help when towing our 19ft TT, currently running 265/75/16's with future plans to add skids, sliders, a CMC and 285's.

After reading this whole thread, watching countless videos on YT, the swap to new gears is both warranted and needed. I've been clocking mileage and hill rpm's during trips to Flagstaff from North Phoenix, and am curious to see exactly how the new gears will respond in similar climbing situations.

Appointment for install is 10/28...first tow trip is in December 2020, keep you posted.