anyone running 31s with 3.55 gears?

E

ericz

NAXJA Lifetime Member
NAXJA Member
Location
CT
I will need new tires soon. Current set up is @ 2.5" lift with 30s. I noticed no difference when I went to the 30s. Spedo was fine too.

Anyone running 31s with 3.55 gears? How is it?
I'm not sure I want to spend any money to regear the Dana 30.
I'm not sure I can buy new tires, wheels and dana 44s all at the same time either.

I quess there are worse problems to have.
The 30s have worked for what I have done thus far - except I want to do more.

Thanks
Eric

:patriot:
 
31's are liveable. It's not like running 33's on 3.55 :P

You'll see it on the hwy more than anything. Don't sweat it... everyone has to upgrade slowly... well.. most of us.
 
I had 31's on the wife's and 33's MTR's on mine, both with 3:55. I will never drive my XJ to Moab again until it's regeared!! Yup 31's are fine but 33's/35's.puke
 
I run 32's on 3.55's w/auto tranny with no problem. Will regear when I get my trailer though.
 
I'm runnin' 32's with no problem. Only drops down a gear when going up hill on the highway a little more than before. No biggie. I also pull a small pop-up camper with it. You'll be fine.
 
32's with 3.55s very liveable I did it for a year while I prepped everything else.

I have brag about my new 4.56 geared spooled d44...fun in parking lots
(Finished install This morning)
If you regear I recommend 4.56 you won't need another regear until 35 or 36s
(4.0 auto only/I cannot say anything about a stick)
 
My heart goes out to all the auto tranny's that are turning 31" tires or larger with 3:55's. Heat is the #1 cause for tranny failure. I know people do it all the time, but IMO you should just regear the Dana 30 to 4:56's. With 4:56's you can always install 32's or 33's in the future if you want, giving you more options. Keep in mind the bug might bite you to want bigger tires. It happens to most of us :laugh3: You only want to regear once, so do your homework. Plus the lower gears will keep your engine in it's power range, thus keeping your tranny happy, so your not shifting out of OD on every hill. You payed for a 4 speed Auto, might as well use all four.

If your only going to be running 31's, I see no reason why you need to install Dana 44's unless you drive like a maniac. The Dana 35/30 set up is'nt bad if you know how to drive and don't push them extremely hard. You can only climb so much with 31's. The 35/30 set up seams to be good up to 35's if driven correctly (personally I would'nt run that big a tire on 27 splines). Dana 44's seam to come in on 33" plus tires and more extreme terrain.

Regearing is far cheaper than swapping two axles. The money you save can be spent on more upgrades :sunshine: .
 
I hope this doesn't end up being one of those extreeeeeeeemly long threads that end up going into the wee hours of the night like the last one I started! :wierd:
 
31's and 3.55's are fine. I went to 4.10's a few months back and noticed I could now peel out. :guitar: Just like someone mentioned above, you'll feel it mostly on the inclines and if there is a slight headwind while driving at highway speeds.
 
Mojo Troll said:
My heart goes out to all the auto tranny's that are turning 31" tires or larger with 3:55's. Heat is the #1 cause for tranny failure.
Click to expand...

Guess I should have added I do run a tranny cooler. First thing I put on when I bought the rig. One mod that gets easily overlooked. Also change the fluid/filter religously.
 
3.55s on 32x11.50s blow. I want my gasmileage back and the pep it had before. going to 4:10s soon.
 
I'm running 30.2" tires (ProComp calls them 31" :laugh: ). I went from 225 x 70 x 16 (27.25") to this and it did affect my performance quite a bit, my gas milage? :passgas: :tear: It dropped from 20 mpg avg. to 15.5 mpg avg. :puke: .
Yes, do install a tranny cooler and consider running around town in 3rd gear. A good headwind will blow me out of OD @ 70mph on the freeway. I'm in the process of re-gearing (4.10's) and installing new 8.8 axle in my 2000XJ.
It will probably be like getting a new Jeep :woohoo:
I'm gonna look into some new rims and (REAL)31"s next summer.
BLUTO :)
 
3.55's with 31's on d30/35 combo isn't bad at all unless you do as stated above and push it, LIKE I DID, if you drive with sense and some caution you will have a joyace jeeping life. Not to say you have to wimp out all the time just be causious. I shredded my front ring and pinion in my 30 with 3.55's but i was pushing HARD....good luck
 
ericz said:
I will need new tires soon. Current set up is @ 2.5" lift with 30s. I noticed no difference when I went to the 30s. Spedo was fine too.

Anyone running 31s with 3.55 gears? How is it?
I'm not sure I want to spend any money to regear the Dana 30.
I'm not sure I can buy new tires, wheels and dana 44s all at the same time either.

I quess there are worse problems to have.
The 30s have worked for what I have done thus far - except I want to do more.

Thanks
Eric

:patriot:
Click to expand...


I have a 99 XJ with an automatic, and I ran 31's for a short period on the 3.55's. Didn't effect me too much do to my short ride to work, but as soon as I could I changed to 4.10's and upgraded my Dana 30 and 35 with Superior axle's 30 spline shafts and ARB air lockers, all this made a strong package and very reliable.
 
I used 33s w/3.55 on the highway for a while (3k), no probs. Even did some very heavy towing for a long distance(1500miles) in mountainous areas, no problem. Dunno about 'froadin with that setup though.

XJguy
 
I've been using this setup with my 4 inch lift now for almost two years, and I can't believe I've gone this long like this. I think it really depends on what part of the country you're in and what the terrain is like, and how fast you drive. I roll along at 75-80 on the highway, and on relatively level ground it pulls without a problem. But, throw a long grade or a strong headwind or pull a sled trailer, and you're gonna be hunting between 3rd and 4th gear a lot. Gets very annoying. The mileage really sucks, too, but the funny thing is that I get the same mileage at 65 that I do going 80, probably cause the engine is closer to it's torque peak at 80, and working more efficiently. I'm planning on going to 4.10's this spring, since I'm not going bigger than 31's ever, and 4.10 is appx 10% higher than needed to regain stock gearing.

As far as heat is concerned with the AW4, it's true that around town there will be more heat generated from converter slippage, but anything over 40mph, the converter is locked and there's almost no slippage. Anything under 55mph and I keep the tranny in 3rd gear with the converter locked and the engine is very relaxed.

Gearing DOES seem to be the way to go ultimately, but you can get by for a while with the 3.55's...
 
Aloha365 said:
I have a 99 XJ with an automatic, and I ran 31's for a short period on the 3.55's. Didn't effect me too much do to my short ride to work, but as soon as I could I changed to 4.10's and upgraded my Dana 30 and 35 with Superior axle's 30 spline shafts and ARB air lockers, all this made a strong package and very reliable.
Click to expand...

That sounds like a good plan for the axles, although I have a chrysler rear.

I was figuring I would go with the tires first, then next month do the gears.
How much lift do you have?
 
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