Topic: Gearing Opinions

[Jeffy]

but i dont have an OD. honestly the problem im running into is most ppl have a 5spd and the option is 4.88s for 33s. i searched online and found a few 2.5 autos with 4.88s (some were running 35s though) but i dont know if they are daily driving their rigs. It seems like every time i settle on a ratio someone brings up a opinion which has me doubting mine...and i def appreciate all the input. Jeffy, do you think 4.56 would be good for a DD jeep. i wheel whenever i can so id like to get some power out of this upgrade..

Hard to say really.  I would run all of the numbers though the gear calculator on www.jeeptech.com at the bottom of the site.  You'll get a graph of each gear and an RPM for any given speed for each gear.  Then decide for yourself.

Personally, I'd probably gear lower and live with the higher RPM at highway speeds.  4.56's in 1:1 and 35's is still a bit too high for my taste.  Although I try to keep under 70MPH and probably around 60-65 MPH most of the time.  If I was going to stick with 55-60 MPH then I'd definitely go lower.  I still catch myself going over 70 MPH but it's usually since the powerband starts coming back.  When I regear I'll probably go with 5.38's or maybe even 5.89's if I stick with 35's and the 5-speed.

If you're not crawling then you can go with high gears.  I'd probably go with a minimum of 4.56's with 33's and still consider 4.88's.

[chardrc]

i wouldn't be worried about runnign at 3200rpm on the highway. if you ask me the 2.5l doesn't make power tell 2500-2800 and 3200 gives you some extra ump to overcome some extra resistance of a headwind or hill or whatnot. if i was to regear it would be 4:88..

[Bounty Hunter]

You are over-thinking the situation, don't worry about the 5spds having an overdrive, the 5spd's 4th gear is 1:1 just the same as your setup in Drive.

Stock tires are not 29", at the most they're sometimes 28" unless the jeep came with the 30" tire package (and I believe that option was most common with the 4.0L engine).  Most 4bangers will be 27" or 28" I believe.

3200 is not screaming for the 2.5L, it's very happy in that range.  3200 is screaming for the 4.0L engine.

[Jeffy]

3200 RPM is good enough to pass people still.

Probably 80% of 2.5L started off with 205/75R15's (27") stock or 215/75R15's (28") optional.

If you're worried, run the stock specs through the gear calculator then run your existing setup and then see what 4.88's will give you.

[Torch_Ind]

Going with 4.88 will only raise your RPM's by 200 over stock tires and stock gearing, and it's best to go slightly lower on gearing when dropping that kind of coin.  It also helps compensate for the large increase in rotating mass, as regearing to 4.56 would only help compensate for the increased tire diameter.  You will be able to get the heavier tires moving much easier with 4.88 gears.

For 33" tires beneath a 4banger, you should regear to 4.88 if an auto and (ideally) 5.13 if a 5spd.  Unfortunately 4.88 is as deep as the stock axles allow.

GO 4.88'S I have 33's and want 5.13 or bigger but have to find axles first with my 5speed stick!!

[Bounty Hunter]

For those with YJ's looking for deep gears, the Waggy D44 front and Isuzu D44 rear are a pretty simple install.  Love my 5.38 gears.

[Torch_Ind]

For those with YJ's looking for deep gears, the Waggy D44 front and Isuzu D44 rear are a pretty simple install.  Love my 5.38 gears.

good to know I have been trying to find a d44 front bronco axle and a rear d44 out of a Cherokee with tow package locally

Are they wide axles or narrowed like the yj?

[chardrc]

ford bronco d44 in our garage is about 59.5" drum to drum (wheel mounting surface)

[Bounty Hunter]

The Waggy and 'Zu Dana44's are approximately the same width as the stock YJ axles, they're both 6lug and discs at all 4 corners.

[Jeffy]

ford bronco d44 in our garage is about 59.5" drum to drum (wheel mounting surface)

Early Bronco axles used to be a common swap.  They are 31 spline small bearing 9's though.  The D44 is more centered and can be a problem if you don't have enough lift or an auto.  The brackets on the housing are also a PITA to remove as well.

[chardrc]

ya we have the accompany 9 inch also...main problem being the willys it was supposed to go into is passenger side drop...   

[Jeffy]

ya we have the accompany 9 inch also...main problem being the willys it was supposed to go into is passenger side drop...   

I would look for narrow track SJ axles for the Willy's.  Pre '84 should be pass side drop front D44. and you can either get an offser rear or a centered one.

[stan98tj]

thanks for all the responses guys! this is going to have to take some good thinking. i dont wanna drop the cash and not be happy with the results. By the way, would there be a loss in mpgs for between 4.56 and 4.88s?

[Jeffy]

thanks for all the responses guys! this is going to have to take some good thinking. i dont wanna drop the cash and not be happy with the results. By the way, would there be a loss in mpgs for between 4.56 and 4.88s?

200-300RPM increase isn't going to make any difference that you can measure.

[Bounty Hunter]

Like I mentioned previously, I think you will see slightly better mileage with the 4.88.  It's a myth that lower gears automatically means worse fuel mileage.  Quite the contrary can be true, as it all has to do with how efficiently the power can get to the ground.  4.88 for you will keep the 2.5L more in it's power band, accelerating and maintaining speed easier, saving fuel in the long run.

I run 5.38 gears with 35" tires and average about 15mpg.  I've been up past 17mpg at times.