The 4.88 mega thread!!

Best calculator I found to show results. http://www.4ws.com/gear-ratio-rpm-calculator

 

Thanks for the info

 

A little more detail on my gear swap and how I use my truck. My 2016 TRD OR 4x4 is my daily driver, trailer puller and trail explorer. It's about 2 years old and I've got 25k on the truck. I work 48hr shifts and am fairly close to my job so I don't have allot of comuting miles. Most of the trucks time has been spent pulling my camper to the mountains and cruising around the desert.
I'm running 265 75r16 general x3 tires which are just under an inch taller than the stock TRD OR tires so I was definatley concerned about being over geared before taking the plunge.
The 4.88s have made a HUGE difference in towing performance. Overall RPMs are lower due to the ability to hold higher gears and trans temps average much lower as well. Towing MPGs are up too. Be aware that diff temps are probably up little since the diff is now expierencing more revolutions but there is no easy way to monitor that.
Daily driving is IMO an improvement as well. First gear is a bit too low but I'd consider overdrive to be a big improvement as it hardly ever shifts out of 6th gear (driving 75-80 mph). MPG has only slightly improved but I'm overgeard with my tire size.
Off-roading has of course also become allot more fun! The first gear that feels bit to low on the road is just right and the extra torque is phenomenal. I recently spent some time on the Oregon dunes and can say I had a blast driving the truck in sport mode (allot of 2nd and 3rd gear) keeping the RPMs up.
Now as far as metal treatments, and break in goes I opted for the standard break in routine. I called around my area and found cryo treating to cost about as much as the gear sets. I know cryo is a must with monster trucks and rock bouncers but I didn't think it'd be necessary for my 275hp truck on 32s... I didn't rem polish either since it would've delayed my install (which I wanted complete before my last trip) and I would've done a proper break in anyway. Break in is simple, a few heat cycles, 1000 miles easy driving, no highway droning and then a few more heat cycles with your trailer if you plan on towing. I changed my diff oil after about 1100 miles and found it to be in like condition, also found very few very small fragments on the diff magnet.
I had AZ diff specialist do the work. Great shop that does nothing but differentials. I'd say they are Toyota experts but they're also pretty much experts in for any vehicle that has a ring and pinion.

 

Great to hear that you're running 32's with this. I'm running 33's (285/70/17) so my anxiety of being over-geared is diminishing.

 

Dude, due the over drive gears being so high I'm pretty sure most owners would be happy with 4.88s on stock tires!

 

That's why I decided to bite the bullet on this upgrade. My truck is only 5 months old with only 7k miles and it's terrible on long drives, especially when I only average 13 mpgs...

 

Gears definitely make those long road trips infinitely more enjoyable. My truck will be a year old at the end of the month with almost 25k miles. It's seen about have the miles prior to the re gear and can tell you that the second half has been a lot more enjoyable! I am also carrying a lot more weight now as well and yet the truck is so much more fun to drive

 

exactly what my plan is - 4.88 w stock tires. ??? What about breaking in the front differential gears- seems like that should be done but running fwd on dry pavements is not a good thing. ???

 

Thanks for the validation. I'm looking to have a "new" truck again!

Question, though, do you have the Shift sense pro and TSB done as well (only if you have an A/T)

 

I'm sure it's fine in a straight line, but why don't you hit some dirt or forest roads for this?

 

I do not have the Shift Sense and since my truck is a 2017, i haven't had the need for the TSB. Having said that, my truck shifts great, holds gears and I have seriously not had a single issue. I can't say enough how easy the truck is to drive. Even fully loaded, with my RTT, camping gear and whatever else, it just doesn't have to try hard at all to get up to or maintain speed. Definitely one of my favorite mods hands down.

 

?? Do the front pinion gear and ring gear function independently of fwd? i.e. front gears turning but axle not locked until fwd engaged? If so then it would be breaking in too during the same time the rear is. otherwise you would think they would mention breakin for each front and rear. ???

 

I have the SSP and have had all the TSBs done for shifting- things are way better but I think the trans hunts gears too much in the "d" mode. Not much more to be done other than regear - which I think will make the difference. Will report back once all is done.

 

Im set to have 488’s installed while on vacation in Phoenix in a couple weeks. I’m going to be driving it back to Utah after the install. I’ll report back on my gas mileage to and from.

 

That's awesome! Who you having do it?

 

SDHQ

 

Solid choice!!

 

They will also be calibrating the speedo and installing a icon leaf pack in the rear.

 

Hell yeah, gonna be like a whole new truck. The icon leaf pack is amazing. I absolutely love it.. rxt I'm assuming?

 

What is RXT?