6MT + 4.88 + 35s; anyone do it?

[AustinL911]

Anyone done it?

I'm considering doing it when I get a JTR but wanted to see if anyone had any experience with it.

I realize it's a little shorter than usual for 35s, but, I have several random thoughts in regards to this:

1. ~4.33 would be about the correct ratio to bring it back to 'stock'
2. 4.33 doesn't account for the power loss from the additional rolling mass, so it would probably be under powered.
3. The 3.6L likes to rev anyways.
4. I'd be OK losing a bit of fuel mileage in exchange for more torque
5. I figure 4.56 would get it back to about where it was in regards to stock power/feel
6. If I went to 4.88, it would give me a slight bump in low end torque.
7. It would certainly make 6th gear more usable.
8. It would be pulling ~2500rpm @ 75mph in 6th, which is about as fast as I ever go locally, save for a cross country trip where I might be doing 85-90, where it would be around 3000rpm.


Anyways, I'm just brainstorming for the future. Anyone have any thoughts on my random thoughts?

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[LostWoods]

Honestly, people ran similar with the 6MT Tacoma with 33's and were fine. You'll spin higher RPMs clearly but that's no worse than the old days.

 

[hjdca]

Anyone done it?

I'm considering doing it when I get a JTR but wanted to see if anyone had any experience with it.

I realize it's a little shorter than usual for 35s, but, I have several random thoughts in regards to this:

1. ~4.33 would be about the correct ratio to bring it back to 'stock'
2. 4.33 doesn't account for the power loss from the additional rolling mass, so it would probably be under powered.
3. The 3.6L likes to rev anyways.
4. I'd be OK losing a bit of fuel mileage in exchange for more torque
5. I figure 4.56 would get it back to about where it was in regards to stock power/feel
6. If I went to 4.88, it would give me a slight bump in low end torque.
7. It would certainly make 6th gear more usable.
8. It would be pulling ~2500rpm @ 75mph in 6th, which is about as fast as I ever go locally, save for a cross country trip where I might be doing 85-90, where it would be around 3000rpm.


Anyways, I'm just brainstorming for the future. Anyone have any thoughts on my random thoughts?

I think I am going the same direction as you. 35s with 4:88.... Right now, with 4:10s, stock Rubicon manual transmission, stock Falken MTs, I get 2450 rpm at 80 mph in 6th. This is a nice sweet spot. Some really good power at 2400, 2500 rpm.... Seems like I get some good acceleration going from 80 mph to 85 mph.

 

[@californiajeeping]

I have done this before and with a 6 speed I would go 5.13s. you'll end up on 37s eventually and it would make since to prepare for it. The rpm difference at 65 is minimal but the torque gain in the lower gears will be huge.

Heck my 84 scrambler has a old efi 4.0l engine 32" tires and 4.88 gears. Runs 2700rpm at 68mph and feels " right". I am in 5th by 45mph and ride it out from there very minimal downshifting engine noise is up there but not bad.

I've had a 6 speed 3.6l jk and it really really likes low gears. Lower the better honestly.

 

[3-pedal-Rub]

6th gear is an old dog, as we all have noticed. Might as well gear it to make it work right! 4.88's sounds ideal to me.

 

[Ericshere03]

Not Yet, i am flipping and flopping in my head about whether to go 4.88 or 5.13. I have 35" KO2s and have no desire to ever go larger, 6 speed manual and I actually want to tow, 5500lb trailer to mexico a few times a year and a up in the mountains another few times per year. I am leaning 4.88, but I have had 5.13 gears in my old LJ rubicon and 35's and loved that setup.

35 + 6speed + 5.13 + 80MPH = only 3000rpm and 4th at 65 is about 3300 (towing gear).

either way 4.88 and 5.13 arent really that far apart. BTW: Dana Spicer makes gears all the way down to 5.38, i do not think strength is an issue.

 

[Ericshere03]

I'm going with 488's on my 8Auto with 35's. Get full use of my 8 speeds on the highway, and be ready for 37's if I ever choose to do so.

I wish this thread would stay 6 speed specific as we are by far the minority and almost forgotten about. like sport fender flares, seems everyone talking tire clearance has rubicon fender flares...

 

[wvyankee2]

Deleted.

I wish this thread would stay 6 speed specific as we are by far the minority and almost forgotten about. like sport fender flares, seems everyone talking tire clearance has rubicon fender flares...

 

[RodRecket]

I was debating between 4.56 and 4.88 on my sport. 33s now but planning on 35s. I would like to add a truetrack but there are no signs that they are being manufactured so considering arb lockers too. Would like to get all the diff stuff done in one shot

 

[Ericshere03]

Finally got my 35’s installed ... a little disappointed in the power ... Haven’t changed gears yet, factory 3.73 installed ... but I’m still 95% 4.88 but crunching numbers for 5.13. I had 5.13 and 35’s on an JL Rubicon years ago and it was wonderful ... this engine is a sprinter and in my mind more build for higher gears. To me 3000rpm at 80 doesn’t scare me and Neither is having 1st as a seldom used granny gear.

Anyone afraid of RPM try driving an old chevy. these engines are so efficient in internal friction and breathing the 3.6 would be like silk . But I never really drive 80 either.
Just thinking aloud, I’ll report back with my decision and review .

 

[AustinL911]

Upon running the numbers, I'll probably go with 5.13 when I do it. I have a sneaky suspicion that running the 3.6 at a bit higher RPM won't absolutely kill the fuel economy and may in fact help it due to being more efficient. We shall see.

 

[Ericshere03]

Upon running the numbers, I'll probably go with 5.13 when I do it. I have a sneaky suspicion that running the 3.6 at a bit higher RPM won't absolutely kill the fuel economy and may in fact help it due to being more efficient. We shall see.

The only think to be aware is the 2 stage oil pump, I wouldn’t want to cruise with the oil pump on the high pressure stage, but I think that happens at 3500rpm.

I drove to California recently with the 35’s and spent some time on the highway in 4th, which I think was 70-75mph (adjusted) with the stock 3.73 ... in the city I stay in 4th as well, even with stock tires I usually stayed in 4th.

Please report back with the 5.13 and 35’s ... that really aggressive, but I think great if you tow (I am saving pennies for a travel trailer). If the ratio is truly terrible, 37s can help with that.

 

[Food2000]

Reviving an old thread here however i just drove gold mountain - big bear and man.. it was tough to crawl given my set up.

6speed manual
3.73 gears
35's with mopar 2' lift.

I am budgeting and planning on adding lockers and regearing 5.13.

I am hoping to use my 6th gear more and most importantly.. be able to maintain a slower rpm/speed without stalling while in 4L.

Any all suggestions or advice is of course welcomed

Pic below from the weekend (meet a gladiator (white) and watching me climb... his suggestions were re-gear).

 

[HONCHO]

yes 5:13 are needed with the manual if you use it, off road or on .

 

[TheHops]

I haven't tried to climb anything particularly heinous yet, but mine seemed to crawl just fine in 4-lo. It just walked itself uphill in first gear. Am I missing something?

Rubicon, manual, 35" ridge grapplers. I run right around 2,000 RPM at 70mph in 6th gear.

Edit: I'm fairly new to regearing, as I've never had to do so before. 35" is the largest I typically go. I know it's probably been asked 10,000 times, but while we're here and on the subject: What would 5.13s do for me on my current setup?

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