The 4.88 mega thread!!

Do you know if they did the master kit on yours or just gears. That's the difference in price. My truck has 600 miles on it so i'm not worried about reusing the bearings but would like all seals replaced.

 

+1 to this.

I had my 4.88s installed December 2019. The change was dramatic with 4.88s, but there was still some erratic shifting at highways speeds. Overall I've been pretty happy for the last nine months.

That said, I finally added OVtune this week. The combination of gears and ovt makes this truck an absolute joy to drive. Do both, you absolutely won't regret it.

 

No i did not use the master kit my truck was new less then 8000 miles on it. You wont need it. I had the master kit just in case but martin said they are to new to need to replace!

 

I don't mean to bother you but what about the pinion seals and axle seals? They need replaced.
Did you watch them?

 

You better check with Martin on that i cant remember if he did or not on those seals.

 

Love what im reading in the reviews of these 4.88 gears. Im in a 2019, AT with a bedrack, sliders, RTT and 33's. So sounds like these are right for me. I was quoted $1,650 from AZ Differential in town using Yukon gears i believe. So looking to get this done soon. Any comments or advice is greatly appreciated.

 

4.88’s will work. I truly think you should consider 5.29’s I’m on heavy 33’s 64lbs ea. And about 300lb total added weight (sliders, Full alum skids, some gear in bed) and truck feels perfect.

 

I would go 4.88 for sure. People also need to be mindful of the fact that 5.29 gears limit your top speed to 83-85 ish mph, 4.88 will limit to about 93-95 mph unless you have that tuned out.Not that you’re going to be doing 80 with all that gear but who knows. I consistently drive 80mph here in SoCal so 5.29 was not going to work for me.

 

I went with 5.29's as well, Love them. Night and Day over stock.

Im on 35's with sliders, armor, bumpers, winch, rack and tent.

 

I drive 80 mph a lot with my truck. 5.29’s and 33” I’m limited at 89mph with my speedo corrected for tires. But there is a new test OVtune with a fix being tested right now.

 

That’s not bad. I’ve heard of others limited to 83-85 mph range. But how is your mileage at that speed? I know at 80 mph mine sucks ass with 4.88 vs with the stock gears. If I’m at 65-70 it’s decent but that too slow for me unless I’m rolling with my Jeep crew.

 

my mileage is pretty bad. But I wasn’t expecting great mileage going with 64lb e load tires. On average around town I get about 14-15mpg. Best I’ve ever got with new setup is about 17mpg all highway. Where I live there’s a lot of hills tho. If it was flatter I’d expect those numbers to be 1-2mpg higher. I usually cruise highway at 65-70mph.

Completely stock I was averaging 15mpg around town but was able to hit 21mpg highway.

 

4.88MT get 19mpg around town, 22-23-24+ on highway, 30 when feathering.....

 

My tires are pretty heavy as well and I’m getting pretty close to the same mileage.

 

what's your setup like, that's extremely impressive mileage

 

Im not sure I believe that. I can barley get 24-28 mpg coming down the cajon pass with the wind at my back and I don’t even need to hit the gas for a good while. Best I’ve seen on the street is 14-16.

 

He would have to be very light and going no more then 60 on flat highways!

 

I get the 22-24 mpg is possible. But 30 even on a stock truck is kinda BS considering my wife’s corolla barley gets that kind of mileage. Maybe downhill but considering what it would take to go up that hill overall mileage would be far less. When I head up to bigbear which is weekly I get crap mileage going up and great mileage coming down so I average like 16-18 but that’s coasting most the way down the hill.

 

30mpg is NOT like get that on a full tank, just saying I can get that down hill, etc pretty normal. But sure, made that up if I said my truck gets 30 mpg. It doesn't.

OTH I can do my normal commute to work, 12 miles at 4AM and get 20 mpg, NO FREEWAY. Just 35-40 MPH back roads. Coming home, some construction stops, traffic 19mpg

Right NOW dollars to donuts my trip MPG is reading either 18.7 or 18.9. Because I idled a bit this tank, dump runs, lumber yard and such with no true freeway driving.

Guys - I am not making this shit up.

I am running OVT latest MT tune, I don't punch it like I did at first. I carry no weight normal, just bikes and like I said some dump runs and lumber runs. What I do, is get it into 5th or 6th ASAP. Use the low end power for the taller gears. Downshift to 4 for hills, corners in 3rd.

Now I guarantee my MPG will drop when cold weather and cold weather gas come on.

 

Glad you cleared that up that’s for sure doable. While taking it easy I could probably get close to the same in similar conditions.