Anybody running 4.88’s with 33’s? (1 Viewer)

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I’m needing to rebuild my diffs, as after 370k I’m starting to get a pinion growl. I tow about 2k pounds worth of off road trailer when I’m headed out on trail. I’m not interested in any tire bigger than 33’s, I’m not doing rocks. I’m torn between 4.56 and 4.88 for gears. I’d love to hear what kind of mileage and rpms folks are getting on 4.88’s. I’m supercharged and have about 70gal of fuel capacity, so unless the mileage drops bellow 12mpg, then I’m thinking the lower gears and 70mph cap would be about it?
lmk your experiencea please
thanks
Maynster
 
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Damn! I couldn’t imagine 4.56 or even 4.88 on an SC rig. I’m rolling stock gears on 35’s and I’m enjoying the rubber overdrive. It does fine in the mountains as most people here drive like crap anyway and have no clue what a gas pedal does.

My rig is N/A and lives on flat land at low elevation, so YMMV
 

zonker

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I have exactly the setup you are thinking about.. 4:88s and 33’s. Personally I love the setup. RPM at 70 is not concerning nor is the sound harsh to my ears. Generally stick around 65 tho. Fuel,mileage went up slightly.. I don’t remember exactly how much. Maybe a .5 mile to the gallon. Uphill grades not as much work for the engine. Ever decide I need 35’s.. gearing would be close to original. Would I do it again.. YEP.
 
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I'm running 4.88s on 33's - but I have a 3fe rig.

It runs at 2700 RPM on the highway at 70mph.

In my opinion 33's and 4.88s are an acceptable solution - BUT there's so many variables. How do you drive? How much highway? Are there hills where you live? Is 70mph fast enough for you? What's your weight? Do you tow?

For me, doing very little highway, and living in a hilly environment 4.88's work. I also like the idea of having a little margin left in my gearing if I decide to go larger. 35's with 4.56's just won't work for my rig.
 
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My cruiser weighs in about 6400 pounds. Bumpers, swing out, winch, and extra fuel. Anytime I head east, which is where any trails are for me, I’m towing over a mountain range, and I’m looking into a cargo trailer conversion as well. Weight weight and more weight.
thanks for your replies and info!
Maynster
 
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I’m over-geared a bit. I don’t tow or have a bunch of extra weight. It’s overkill for the city, but I head up the mountains a lot and live at 6,000.... So I’m happy with it. I can easily maintain 60moh going up to 10,000’ plus.
 

LINUS

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If it’s anything like 5.29’s & 315’s (34.5”) - at sea level my limiting factor was not wanting to run over 65-70m-h max due to extended RPM range on motor.

But I don’t know/ have the chart for equiv’s - I know my LX450 had 4.56’s for awhile & the PO / my friend went to 4.88’s due to 4.56’s not being an appreciable ‘jump’ from the stock 4.11’s.

That was his opinion & he wasn’t on here much, but that same sentiment has been echo’d plenty here.

I’ve never driven a 4.56’ed 80, so I have no personal seat time as a driver - I rode in the LX450 just twice before he went to the 5.29’s & eventually I bought it from him as that.
 
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That’s kinda my concerned about running about higher rpms. The 4.56 would still be 6 or so percent lower than stock with the 33’s. I don’t wanna spend this chunk of change again. Lol. I tried running in 3rd gear about 2600-2700, it runs smooth and actually quieter? Dunno
 

LINUS

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Just a thought here, but what about just R&R the pinion bearing, and maybe research those lower transfer case gears?

I’m loosely sure some vendor made a set that lowered both the hi & lo ratio TC gearing - I know the lo only is real familiar, but maybe someone here can jog my memory about the kit that addressed both hi & lo range.

Not like 33’s are going to make you torque & strip the pinion, if you were doing 37’s or 40’s & tried to make ratio all in the TC then yeah - that’d be an issue.

Doing just a pinion bearing & if you even paid to do the TC gears, that’s still probably cheaper & works for your useage.

:meh: - Just lobbing an idea your way.

— still not sure who did those TC gears though.
 
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I have looked into that. They’re said to be a bit noisier than stock? That’s subjective of course. I’ve a spare set of diffs, and it’s the right time to re gear and set some e lockers in. I’m looking to do the 25% reduction in the transfer case low gear probably next tax season.
the cost for both done in the case is about equal if you drop third members off to be done.
 
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I'm running 4.56 gears on 33s and very happy with it. I can easily cruise at 90 on the hwy if I want to. For me, it's a perfect balance between low and top end. I'm not SC'd or turbo'd. Not sure what RPM I'm pulling at 70 but it's not high or loud. My tach has gone wonky and no longer reads accurately so I can't measure.
 
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Just a thought here, but what about just R&R the pinion bearing, and maybe research those lower transfer case gears?

I’m loosely sure some vendor made a set that lowered both the hi & lo ratio TC gearing - I know the lo only is real familiar, but maybe someone here can jog my memory about the kit that addressed both hi & lo range.

Not like 33’s are going to make you torque & strip the pinion, if you were doing 37’s or 40’s & tried to make ratio all in the TC then yeah - that’d be an issue.

Doing just a pinion bearing & if you even paid to do the TC gears, that’s still probably cheaper & works for your useage.

:meh: - Just lobbing an idea your way.

— still not sure who did those TC gears though.
I think you're referring to the T-case gears by Sumo.
 

LINUS

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I have looked into that. They’re said to be a bit noisier than stock? That’s subjective of course. I’ve a spare set of diffs, and it’s the right time to re gear and set some e lockers in. I’m looking to do the 25% reduction in the transfer case low gear probably next tax season.
the cost for both done in the case is about equal if you drop third members off to be done.

Cool, if tou explored the cost then you lnow more than me.

My 4.88’s / 315’s are about like stock in the black 80.


I had e-lockers to retrofit & sage wisdom on regearing those was to just pay a pro like Zuk or Just Differentials - it’s more complicated than aftermarket lockers in open diffs / K292’s as was told to me.

I’d done 2 Ford 9” prior, and a Cheb 10 bolt - was still told to “cut a check, get a milage warranty“.
 

flintknapper

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I’m needing to rebuild my diffs, as after 370k I’m starting to get a pinion growl. I tow about 2k pounds worth of off road trailer when I’m headed out on trail. I’m not interested in any tire bigger than 33’s, I’m not doing rocks. I’m torn between 4.56 and 4.88 for gears. I’d love to hear what kind of mileage and rpms folks are getting on 4.88’s. I’m supercharged and have about 70gal of fuel capacity, so unless the mileage drops bellow 12mpg, then I’m thinking the lower gears and 70mph cap would be about it?
lmk your experiencea please
thanks
Maynster

Lots of things to consider here I suppose. IF your Cruiser is used only for recreation and you don't travel hundreds of miles to get to your destinations....then I'd say 4.88's might be the way to go.

IF you also use your Cruiser to daily drive or use it often without pulling a trailer (extra fuel, etc) then I'd be content with 4.56 gearing. You are already SC'd which is primarily an advantage in High Range. Unladen.....I expect you are satisfied with the power you have now (on 4.11's). Going to 4.56 would give you an extra margin of torque without putting you at the upper end of the flat spot in the torque curve.

The 1FZ-FE has a very nice torque curve between about 1800 rpm and 2600rpm. Personally...I have found 2000-2200 to be the 'sweet spot'.

If you can achieve the power you want/need at 2200 rpm (highway speed) why spin the engine faster for no noticeable gain? IF you really, truly will NEVER go larger than a 33" tire, you don't rock crawl and you use your Cruiser for purposes other than off-roading....then carefully consider 4.56.

Either gear set (at highway speeds) will have you in the 'flat part' of the torque curve (which is amazing with this engine). Being SC'd only helps with this. So bottom line is: What type of driving do you do and under what conditions. Forget about off-road, you'll be in Low Range for anything serious there.

1FZ-FE-torque-HP.jpg
 

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