whose running 33's with 3.55 gears?

seems everyone is mentioning their setups, so just curios, i got the 5 speed and 3.07s. I am running some no name ATs right now, 30x9.50, and it feels fine, but im looking into upgrading to 31x11 thornbirds or even 31x12.50 thornbirds. I know that this will dramaticly hurt performance, paticularly with the 12.50s, but has anyone had experience with a similar setup? I plan on upgrading to a 3.55 front/rear end over the summer, or if possible 3.77s or something aorund there, but I dont have the funds to do it now, nor do i have the time.
 
My '97 XJ 4.0 w/ 5-speed and 31x10.5 Dunlop RV's was a dog with the 3.07's, could only use 5th gear going downhill. When I regeared to 3.73 it was much better. Now my '87 MJ 4.0 w/ 5-speed worked just fine with 31's and 3.55 gears (swapped axles from the original 3.07 gearing,) I'm curious to see how it works with the 33's I just installed.
 
themangeraaad said:
I am running some no name ATs right now, 30x9.50, and it feels fine, but im looking into upgrading to 31x11 thornbirds or even 31x12.50 thornbirds. I know that this will dramaticly hurt performance, paticularly with the 12.50s, but has anyone had experience with a similar setup?
Click to expand...

the thornbirds will be the biggest performance loss...

people cant even give thoes tires away...
 
any tire recomendations, I mean, im looking in the 31x11 to 31x12.50 range, and i need pretty decent highway drive. I mean, looking around I found that the thornbirds are claimed to be decent for highway drive, but are still agressive, granted those are mostly from dealerships, but i found several reviews that praised them. Any recomendations that woudnt kill my perfomance too much for now, until I can upgrade to 3.55s or something? I know anything will hurt performance, but its running great and 5th gear is fine (a little doggy in 5th uphill, but htats expected) with the 30x9.50s I am running now.
 
Hm, based on everything here, 33s and 3.55s come across as pretty much the end of the world. I was near convinced to regear when I get my 33s, but I just rode today with a friend in his XJ with 33 BFG ATs / 3.55s and it seems fine. The reason I wanted to take a spin in his was to merely see how bad it was and if the hype is true. For me, it's definitely not. He could still do burn-outs with them and it cruised fine, keeping power no problem. It seemed to barely struggle with them if it did at all. The only weak area seemed to be brakes. Now, as far as hills are concerned, it will probably be less than great, and the gas mileage will surely take a hit, but as far as drivability goes, it's definitely do-able. I'll most likely buy his tires from him and then gear later. I can always go to the salvage yard and get a set of 4.10 axles from a 5 speed.

Just my $0.02...
 
I recommend staying with the 30" size until you can upgrade the gears, but that's just my opinion. I absolutely hate the sluggishness that comes with big tires and stock gears. Guys have been known to get a pair of junkyard axles for less than the cost of a set of tires. Heck, some have bought entire Jeeps for under $300 (I have twice now). try car-part.com or hit the phone book for pull-your-part 'yards.

As to 3.55s and 33s, the automatic trans will partially mask the difference, but the trans is working extra hard and will wear out sooner than it should. At the very least, an aftermarket tranny cooler should be seriously contemplated. I never truely understood why owners hesitate doing gears. Not only is it the right thing to do, the extra oomph is just awesome! Single best mod you can do in my opnion.
Jeep on!
--Pete
 
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im running 3.55's with the 4.0 HO auto tranny, 33x10.5's i just got them on today, its not as bad as i thought, its livable but i would like to go 4.56 once i get the cash. for now it keeps me goin the speed limit
 
LoneRanger said:
I finaly looked to see what I have in the jeep and the sticker on the axle tube says I've got 3.55's now with 31's but I would like to go to 33's~


whose runnin 33's with the 3.55 ratio? I would like to go 4.88's and 35's but that aint happenin.



L.R.
Click to expand...
What rear end is in it?
If it's a Chryco 8.25 you're not putting 4.88s in anything.
 
i run 33x12.50's on the stock 3.55's and yeah it kind of sucks in town but i an't afford to do gears right now and it's driveable. what i want to know is what mpg people are getting w/ 4.56's
 
1990 XJ
Tired 4.0 165K overheated once by GF to point of Sieze, no smoke :)
Leaky rear main seal, 13mpg avg. 3.55's w/31x10.5's on D30/35 open/open.

Handled everything I pointed it at up at Trask in TSF just fine.

Going to trim for 33x10.5's and wait till can afford D44's to go to 35's

I have a chance to pick up 4.10 ring/pinions for the D30 and D35 for 125 bucks.
I'm thinking these would help, without having me over-reving on climbs......

Primary use is on roads just to and from trail runs till can setup a towbar and drag it around behind my '98XJ.

Does this seem like a good idea or.......?
Would 125 for those be a reasonable deal or should I walk away?

Thanks much!
 
Do you know how to set up the gears?
 
JT_Law said:
1990 XJ
Tired 4.0 165K overheated once by GF to point of Sieze, no smoke :)
Leaky rear main seal, 13mpg avg. 3.55's w/31x10.5's on D30/35 open/open.

Handled everything I pointed it at up at Trask in TSF just fine.

Going to trim for 33x10.5's and wait till can afford D44's to go to 35's

I have a chance to pick up 4.10 ring/pinions for the D30 and D35 for 125 bucks.
I'm thinking these would help, without having me over-reving on climbs......

Primary use is on roads just to and from trail runs till can setup a towbar and drag it around behind my '98XJ.

Does this seem like a good idea or.......?
Would 125 for those be a reasonable deal or should I walk away?

Thanks much!
Click to expand...

rustys off road has a set front and rear complete kits for less than 400 bucks, i think thats a good deal, look into it
 
Labor is expensive. Might be cheaper to get junkyard axles. This is especially appealing if you can use the opportunity to upgrade the axles at the same time. If you have a CAD or the smaller ujoints up front, you can grab a 94+ 2.5L XJ front axle and take care of both problems. Out back you can hunt down an XJ 8.25 or Ford Explorer 8.8 with 4.10s and posi and even disks for 97+ Explorers. car-part.com can help you track them down. Stay away from the other 8.8s. Rangers, cars, vans and trucks use either inferior versions or they are too wide. At least upgrade the rear. I wouldn't sink a dime into a Dana 35.
Jeep on!
--Pete
 
regarding installing a ford 8.8 rear end.. how well do they match up for width, and paticularly, how well does the rear yoke match up for the U-joints... does the 8.25 rear end and the ford 8.8 rear end have a comparable rear u-joint size or how would the mating of the rear driveshaft to the ford rear end work out, just curious before I get myself into trouble dropping money into a rear end that requires more money and mods to fit properly, and also, is there any problem actually bolting it up to the leafs, I have replaced my rear end already but that was with a stock unit, so I am not sure what will mate up properly (in terms of both Ujoints and actually fitting in to be bolted up).

Also, anyone know how the 5 speed 6 cyl will run with 4.10s in it and 31' tires, paticularly for mileage, I know 4.10 should be plenty to keep the power I need for off road, but how well would it drive for mileage and such in general?
 
No problemo, CAD stands for Central Axle Disconnect and is a shifting mechanism located inside the passenger side axle tube. It'll be the large blob of cast steel halfway between the pumpkin and passenger side knuckle with a couple vaccum lines running to it. When the t-case lever is shifted into 4wd, a vacuum switch sends vacuum to the diaphram on the CAD which pulls on a fork which shifts the collor that connects the 2 halfs of the axleshaft. It came with the part-time t-cases from 84 to like 93. If you have full-time awd, then you won't have it and you will have a 1 piece shaft on the passenger side. The CAD was designed to decrease drag and improve mileage, but it really didn't do anything significant enough for Jeep and it was dumped. When it works, it works fine, but lots of things can and will go wrong with it (especially since our Jeeps are so old).
As to the u-joints, if I understand this right, the ABS equipped Jeeps in the late 80s and early 90s got the bigger joints (Dana 44 size). After 93, all Jeeps got them.
Jeep on!
--Pete

126875786.jpg
 
Pete M said:
, the ABS equipped Jeeps in the late 80s and early 90s got the bigger joints (Dana 44 size). After 93, all Jeeps got them.
Click to expand...
it was after 95 or 96
 
Is it that late? Oh well, look for an ABS one then I guess.

The 8.8 is, what, like 5/8" more narrow on each side? It's really close. The 8.25 should bolt right up with the 8.25's hardware that you grabbed from the junkyard. The 8.8 is a conversion to a different brand of vehicle and will require new pads welded on. Make sure you grab the flange-to-Ubolt adapter and the U-bolts/plates with the axle from the junkyard.
A search should bring up more XJ/8.8 info.
The smile that 4.10s put on your face will far outweigh any adverse effects :D , but no, I don't believe you'll have any problems.
Jeep on!
--Pete
 
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