That's because you have the old 3-speed auto which is much less picky. Ideally you'd want 4.10 but it would still do fine with 3.73, just like you said.
Is 33s on a stock 2006 TJ with 3.73 gears asking for trouble?
- Thread starter CMTJ
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That's because you have the old 3-speed auto which is much less picky. Ideally you'd want 4.10 but it would still do fine with 3.73, just like you said.
The OP could run 33's with 3.73 and leave it out of overdrive, that would make his trans mimic the old 32RH gearing. His hwy speeds would be around 2000rpm at 50mph, 2400 at 60, and 2800 at 70. Totally doable and Florida is flat as can be anyways. But forget about using overdrive, even at 70 it would only be at 1900rpm, that's really lugging the engine.
I have the old 32RH and regeared to 4.10 and it's really spinning some high rpm's on the hwy, over 3000 at 70. Kinda wished I had gone with 3.73 instead.
I have the old 32RH and regeared to 4.10 and it's really spinning some high rpm's on the hwy, over 3000 at 70. Kinda wished I had gone with 3.73 instead.
It don't get much flatter than here in South Fla. Guess thats why my 33's and 3.73 can hold their own around town.
I'm happy with my '06 with 33's, 6 speed manual and 3" lift.
They seem to work well together. Since it's manual I get to choose my shift points...keeping the rpm's where I want them.
05 LJ 3.73 auto 33s. No problems or complaints. I recommend installing a transmission cooler regardless of tire size.
Highway gas mileage. My sons JKU with 3.21s gets 25-30mpg. My old YJ with 3.07s and 33s got 25mpg on the Interstate, 4th gear. My TJR, even with a new motor only just hits 19mpg if I stay under 60mph and drive barefoot. If you expect great responsive power in top gear yeah you need deep gearing. Me, I just drop a gear or two.
yeah, most of us keep quiet about wanting tall gears. Some of you guys can be pretty rude when someone expresses that choice.
Hmm...that's something to think about. I just thought there was optimal gearing for certain engine, transmission and tire size combinations. I have the 3.73 with a 6-speed and 31's but am going to get 33's next time.
How you actually USE it is what counts. A pure trailer transported rock crawler yeah start with 4.88s or deeper. But if you commute and off road.... just not going stupid on the waterfalls.... 3.73 is a great all round ratio... most of us daily drivers call 3.73 with 33s the best all round combination.
Back in the 70s my first Trans Am, a '70 had 4.10s and the 455SD. Lay rubber shifting into 2nd. But go 10 miles on the interstate and you needed ear plugs. TA number 2 was a '75 400 automatic with 2.73? rear end. 90mph all day and feeling fresh when you got out of the car. There is no 1 gear which is right for any tranny, tire, engine combo. End use is what determines the best gearing.
The Audi S8 hits 150mph in 5th gear. It loses top end in 6th, 7th and 8th gears but that is what makes it clean, efficient and comfortable.... Hard to find a more comfortable performance sedan than an S8.
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Yes & No.
If I drop to 5th, if guys with a 5speed drop to 4th, if you drop to 3rd or of an old TJ Automatic stays in drive, we are all in the same spot. Direct. But I agree that 4speed OD is plain silly.
I've had my 42RLE with 33s for a couple of years now, and I'm not hating it. I live in the hills, and don't run the highway much. Oddly enough, I leave overdrive on when in the hills because it seems to have different shift points, than if you turn OD off. I typically only turn the OD off when I hit the highway, or driving over 50mph for any length of time.
This hasn't been the case for me at all. I have personally never known anyone to get 25 mpg in a Jeep (you're in Canada so maybe you're calculating it different than me?). Regardless, about the max gas mileage I've ever seen from a 4.0 or 4.2 (in reference to your YJ) in the US is about 18-19 mpg. Most get less than that, and most of those guys getting less are running 3.07, 3.55, or 3.73.
I used to have 3.55 with 31's. This is a '94 YJ 4.0 with an AX15. I didn't enjoy it. Before I knew better, I used to use 5th gear on flat ground because I figured it was good for it. At about 65 mph, I'd be turning about 1900 rpm. In 4th gear, I'd turn 2500. Keep in mind, this is on flat ground so it's not struggling to keep speed with either of the gears. I got better gas mileage in 4th. 17.5 compared to 15. I compared on multiple long hour trips. Low rpm doesn't equate better gas mileage.
I'll give another example. Now, I have 4.10 on 31's. Same YJ. I took a trip for 6 hours just the other day. I was driving at 70-75 mph for most of it at about 2750 rpm average. It's a range of about 2650-2850 at those speeds. Whenever I reached the 55-65 mph speed limits, I kept it in 4th which generated anywhere from 2500-3000 rpm. For a straight hour I was running 3000 rpm at 65. I managed to get 17.8 mpg that day.
I will be going with 4.88 and 33's next time around. It'll put my rpm right at 2900 at 70. I don't expect my gas mileage to get worse at all. I expect the performance will be great and the gas mileage still acceptable.
Good plan.
This actually took me by surprise, Jerry. Usually, you suggest 4.56 for 33's with the 4.0 5-speed combo. Regardless, I've run the numbers countless times and driven the setup once and I loved it, I look forward to getting it in the near future.