Birty Dastards Jeep Club
Tech Forum => Workshop => Topic started by: Yakko on February 25, 2015, 10:21:33 AM
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Hi.
I'm confused about gearing, hoping someone can help me make sense of it all.
I've got a 1998 TJ 4.0 manual, according to the build sheet I got from Jeep its got 3.07 rear axle ratio in it currently (D30 front D44 rear).
I've put 31s on it, but wish I'd gone for 33s and am slowely thinking about a regear, I'd like to get back to standard speed to rpm ratio.
All the forums suggest that 4.56 is the right ratio for 33s, but if I look at a gearing calculator (e.g. http://www.jeep4x4center.com/calculators/index.htm) it looks like 4.56 is way too high and that 3.77ish is closer to factory.
This feels right as 4.56 is nearly 50% higher than 3.07, but the wheels are only 14% taller.
What have I missed?
I know I could just accept the advice of the various forums, but I'd like to understand it myself!
Thanks
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Ahhh, it's just hit me. Is it because 3.07 is particually tall gearing for a Jeep and that people are recommending 4.56 to get back to factory ratios for Jeeps that left the factory on shorter gearing?
In which case, why did Jeep put 3.07s in my Jeep when others are much shorter geared?
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Yakko, you have just made me think to check what ratios I have on my 97 :icon_winkle: Runs well on 31's though!
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Mine drives ok on 31s, but is noticeably less perky than it was on the 28.8s it came out of the factory on. Most noticeable climbing hills in 4th.
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The diameter / circumference of the new tyres is one thing but normally on modified Jeeps there is a combination effect of bigger tyres, higher suspension, more weight and the result of more drag. This means the lower gears (higher numbers) is what works best / feels best.
As most Jeeps are great at high motorway speeds over the speed limit and the engines are actually quite happy to rev a bit then no harm really comes from going a bit low with the gears.
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Tis weight and drag.....
Mathematically 4.56 is OK for 35s......
I had 33s and it was great ...it did what it should, went up to 80 if you really wanted and would go down to 30 in 5th......
I then put 35s on and was a slug.....ll60 was OK any more and you knew you were just pissing fuel out the back..... Below 45 50 it was gagging fora down change.......
Was great off road though :icon_twisted:
Now I've got 40's and 5.38 in the axle .......but although mathematically correct I bet the weight would be against it if it ever went on road :hysterical:
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33s and 4.56 is the way to go but
If you've gone up to 31s but wish you went to 33s why not do a proper job and go 35s and 4.88?
I'm on 37s and 5.38 but not driven it yet, not stock axles either :strum:
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Thanks for all the quick replies all.
Ezz, I'd heard that the standard axles didn't really like 35s? Also, I don't really want to lift much more than 3.5 inches otherwise it looks like it becomes a bit of a ballache.
Thought 33s were a good compromise of size, ease of install and ability to keep using the car as Dog transport (which is how I justified it to the Mrs in the first place!)
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Hmm. This is starting to sound like it's going to be more expensive than I'd hoped.
Am I right in thinking that if I can find a 2.5L TJ, the diffs from that are 4.10s and should just drop straight into my axles? Does it matter that the 2.5s won't have Dana 44 rear axles?
Err, I guess what I'm saying is that I haven't got a clue. What's the cheapest way of getting my axles OK for 33s? I think 4.10s would be OK.
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I thought all the TJ,s over here came with d44 rear and d30 front not just the 4.0L, if I am wrong no doubt someone will come along and shoot me :wave-fingersmiely:
On the Gearing front I have 4.88 on 33,s, next set of tyres will be 35" but still think if you use your TJ more onroad than off 4.56 and 35" would be fine. if you can get a pair of 4.10 Cheap and could do it yourselve saving money it would make a difference and 33" would be tolerable but 33,s on 3.07 is awful, what ever you end up doing you also have to order a speedo drive cog for your gearing and tyre size to correct the speedo.
Have fun and if I have learned one thing, the words Jeep TJ and Cheap rarely end up in the same sentence. :banghead:
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All UK spec TJs have D44 rear axles. 4.11 is OK for 33s, to be honest, I find 4.56 is a liitle low for street use anyway. If you can find a decent pair from a 2.5TJ, it's a good low cost option.
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OK, thanks chaps, that's really useful.
Awaiting a quote from someone to fit 4.56s. In the meantime, someone sell me some 4.10 diffs!
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33" tyres and 4.56 gears work in manual gear box - one must also consider automatic, so 4.11 works equally well...END OF !!!
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Got 4.10 on 31's in an Auto TJ, its only 3 speed & needs it for downhill control
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Don't know why I didn't consider 4.10s before, just done the gearing calculator (http://www.grimmjeeper.com/gears.html - bloody good) and that looks like it'll be spot on.
Anybody got a bottomless pile of 4.10 diffs? Or know where I could get hold of some?
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Might have found some complete axles off a 2.5 TJ. Are the axles a straight swap? Assume the swap is pretty easy? Basically had the axles off to fit my lift anyway.
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TJ to TJ should be a straight swap.....
You'll also end up with useful trail spares like the rear half shafts and the front drive shafts with the UJs already there for when you have an Offroad redmist moment. :icon_twisted:
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I have a TJ with 33's on it was awful on the standard 3.07, I couldn't use 5th at all. I went for a Cherokee 2.5 hpd30 in the front and changed the rear diff and r&p to match, so it's now running 4.1 ratio. I love it, will do 80 on the motorway no problem and will pull 30 in 5th now. It's the cheapest way to change gearing I could find.
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Thanks for your continuing advice all.
Now I just have to justify to myself that its worth it all to go from 31s to 33s.
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With 33s you have a wide choice.....
Apart from the many tread patterns......some suitable only for road and some only for mud and Off road, you then have the choice of width...... Super skinny 9.50 that used to be popular with mud lovers and the staple of the Jeep community the 12.50
Add to that the 10.50 that's been around a few years that allows fitment without the need for wider arches and is lighter so giving better acceleration and mpg
So much choice :icon_twisted:
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Even 16s / 17s and metric tyres as there are quite a few 32/33" ones to choose from.
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Right, pair of 2.5 TJ axles on their way.
I've also bought a pair of Aussie Lockers, they were surprisingly cheap and I figured it'd be easier to put them in while I had the axles off the car. They seem a little marmite on the forums, but I've experience driving rear wheel drive cars with brutal LSDs, so I'll see how it goes. Can always take the rear out if it's a pain.
Getting them delivered when the Mrs is out as the honeymoon fund just took a hit.
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Good work :icon_super:
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Sounds like fun - I'd be interested how you get on in case we go down that route :)
Might have to pop over and take a look some time :icon_biggrin:
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Want to sell me your d44 rear?
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Want to sell me your d44 rear?
With the 3.07 in? Assuming I get the new one in and working ok, sure.
I'll PM you when it's done.
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Before I changed my Axles I had a powertrax locker in the back, it made for an interesting drive in the wet lol, It just didnt want to unlock. it did get better as time went on but knew it was going to be a nightmare in the snow and skitty conditions as its my daily. Offroad though what a piece of kit.
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Yeah, I'm hoping it won't be too much of a handful in the snow as that's when I enjoy my car the most!
Someone summed it up as Can't Control Where You're Going, But You Won't Get Stuck Getting There.
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try an aussie locker in the front in the snow........ or rather dont. It made it for an "interesting" ride.....
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Understeery?
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No steery :003:
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oh crappy more like
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My 2000 2.5 TJ had 3.73 gears...not 4.10 from the factory. D30 front and D44 rear with LSD.
Then bubba kindly re geared it to 4.56 for me.
I thought it was only the 2.5 Cherokee that had 4.10 as standard....
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Hmmm. That's worrying, because I don't want 3.73s to turn up at my door!
Is it an auto?
Edit: Yeah, according to http://www.quadratec.com/jeep_knowledgebase/article-91.htm 3.73 was on the autos.
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Mines a manual. Never seen a 2.5 auto TJ in the UK.
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No 2.5 autos over here.
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Hmmm. No idea why you got 3.73s then. Fingers crossed that when mine turn up they are 4.10s.
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Fingers crossed for you too!
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I have requested a build sheet from Jeep and will post results shortly....
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Was wondering if there was a towing option to reduce the gearing, but seems unlikely on the 4 cylinder.
I found the build sheet really interesting - was impressed that they had records for all the cars going back that far. 18 years!
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Want to sell me your d44 rear?
With the 3.07 in? Assuming I get the new one in and working ok, sure.
I'll PM you when it's done.
Yes the one in your wrangler now with the 3.07. Thanks, I hope the swap goes well.
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Did the D44 in 2500cc cars come with the TrakLok LSD?
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D44 came in all TJs ......we were lucky. Don't think they had LSD, and if they did it was the clutch type that was prone to wear out......so by now it will be worse than useless .......time for a locker when the jar of 5p coins have increased some more :icon_super:
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Ta. I'm actually thinking about whether or not the carrier will take a lunchbox locker. As far as I know all UK 4L TJs got the TrakLok LSD in their D44s, I'm wondering if the 2.5Ls did too.
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The tags on the axle will answer that question, bit wire brush and you should be able to read them.
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Or look inside to see the bits.
Got a feeling you need and empty IE non LSD carrier to then put a Lockrite aussie locker or Detroit in.
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Did the D44 in 2500cc cars come with the TrakLok LSD?
Mine had the traklok LSD. Put an open carrier and gears in when it was re geared. So much nicer on the road and not had an issue off road yet.
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Thanks Graham.
Guess I'll open it up and find out when the axles arrive. If it's got a Trak-Loc, i'll go with that (and stick new clutches in at some point if required). If it's open, i'll try a lunchbox (Aussie) locker and see how that goes.
Did you get your build sheet back from Chrysler?
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Whatever you do don't put anything in the front.......I did :jpshakehead:
Took me on a very expensive journey of Free Wheeling Hubs and stuff...... Lots it shake shimmy and wobble.......
And at the last moment I went ARB.......
Bliss. Should have done that in the first place.....
Traction when you need it and turning tight off road also....... Worth saving up for...... :icon_super:
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Indeed, ARB in the front is the way-to-go.
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True Tracs front & rear are probably the best compromise for on & off road IMHO :icon_winkle:
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Still waiting for the build sheet....
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True Tracs front & rear are probably the best compromise for on & off road IMHO :icon_winkle:
When you are ready for long trousers the Short Tracks will be soooooo last year.
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True Tracs front & rear are probably the best compromise for on & off road IMHO :icon_winkle:
When you are ready for long trousers the Short Tracks will be soooooo last year.
Not lockers I'll grant you but very capable & still makes the Jeep usable on the road, it aint no trailer queen princess :hysterical: :hysterical:
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I removed my LSD as it was like 80% of others and didnt work and fitted a powertrax locker, you can get them for the LSD carrier and the open diff carrier.
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Well, that was frsustrating.
New axles (4.10s) were supposed to be delivered, so left the Mrs in the house to sign for them. TNT turn up, knock on the door, driver says he's got the axles, but no way of getting them off the truck, so he just left. :011:
I phoned up and had a rant, they're coming back tomorrow with a truck with a tail lift.
TNT think that the weight for 2 TJ axles is 245kg! That can't be right, I've moved English axles (Land Rovers) around on my own, and I'm no weight lifter!
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I can sympathise, I had 1500 slate roof tiles delivered and the guy just turned up with them in 3 crates in the back of a truck expecting me to have a telehandler or something.
A few phones calls and you'll get it sorted :violence:
I wouldn't be surprised if the front is 100kg if it's got shafts, brakes etc, not sure about a rear one as I haven't moved one recently.
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With all its bits a front dana30 is an unpleasant struggle by yourself maybe 200lbs
The rear less so.......150lbs
At least that's what they seemed like to me.
My 1 tonne axles were painful and dangerous to lift with two of us :hysterical:
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Here's a question. Going to start this first thing tomorrow morning. I use my TJ as my runabout as it's miles more fun around town than my daily driver Volvo.
If I get one axle done, I can still use the car, even though the axles will be different ratios as long as I don't put it into 4WD? The front axle will just be free-wheeling, right?
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Leave the front prop off!
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Good point!
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You can leave the prop on, just Dont put it into 4 wheel drive. drove mine for a couple of weeks with front 4.88 and rear 3.07
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Need some opinions Birtys.
Axles turned up today - predictably they're 3.73s instead of 4.10s. (No tags on the axles, but if I turn a rear shaft once, the prop goes round about 3 and 3 quarter turns).
Spoke to the seller who says he'll take them back.
OR do I just go with 3.73s instead? I've done the gearing calcs, there's not much in it (only 10% difference between the two ratios). Can't see me ever going over 33s to be honest. Seller is looking round the yard (they're a Jeep breaker) for some 4.10 axles, but I'm not very confident.
I thought I'd go with plan A and get my 3.07s geared to 4.56 but I'd need new carriers for that anyway, as my 3.07 carriers won't take 4.56s.
What do you think?
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Your well and truly fooooked, send the shiet back if you can.
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3.73 will be spot on for 31s and you will notice a definite difference. IF you can get a full refund it makes the decision more tricky. I think I'd end up fitting them and just saving for repeat and lockers at a later date.
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Thanks, but it's 33s I want to run.
Gearing calculator suggests that 33s on 3.73s will actually be better than 31s on the 3.07s (which is my current set up), this ignores the extra weight and wind resistance of the larger tyre though.
Yes, can get a full refund, but can't find 4.10 axles anywhere.
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I would get the refund and sit on YA wedge.......
The cheaper alternative would be XJ a cherokee 2.5 petrol axles ....also 4.10:1
Front will fit no prob......the rear had leaf springs but you can get all the bits to weld on. :icon_twisted:
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I drove my TJ on 4:10 with 35" tyres and it was horrible
I'd guess 3:73 and 33s would be similar
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I drove my TJ on 4:10 with 35" tyres and it was horrible
I'd guess 3:73 and 33s would be similar
Indeed...
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I wish I'd have spotted the post earlier. I'm pretty sure the only TJ with 4:10 was the rubicon (although the rubi was also D44 front)
I believe the 2.5 XJ had 4:10s and I think it crept into myth that the baby TJ did too.
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I drove my TJ on 4:10 with 35" tyres and it was horrible
I'd guess 3:73 and 33s would be similar
Yes, pretty much bang on the same according to the gear calcs, although both better than the 31s on 3.07 I have now apparently.
I wish I'd have spotted the post earlier. I'm pretty sure the only TJ with 4:10 was the rubicon (although the rubi was also D44 front)
I believe the 2.5 XJ had 4:10s and I think it crept into myth that the baby TJ did too.
I'm not sure that's right, everything I've read says the 4 cylinder TJs got 4.10s.
E.g. http://www.fourwheeler.com/project-vehicles/154-1001-jeep-wrangler-tj-buyers-guide/
I don't know why some got 3.73s. (That said, your 4 cylinder was 3.73s, and I've got 3.73 axles here, so evidence suggests otherwise).
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What did I think about / spend money on before I got my Jeep!?
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If they didn't cost a fortune, stick them on, you'll notice a considerable improvement. Keep your others for later when you can rebuild them at your leisure if you still feel the need. Remember you're getting 4 spare halfhafts, hubs etc. as well as the axles in case you need them.
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Is the Axle ratio difference from what you read not just USA spec and not Uk spec, after all we got the dana44 across the range where they got the 35 .
If they were cheap enough sling them on and do the changes to your current axls as you go along, yes its not the jump in gearing you wanted but you could prob live with it on 33,s till you sort the others at you leisure.
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Yeah, could be a US vs Export spec thing.
Thanks for the opinions chaps - this is a great forum. :icon_super:
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fit them and send your old ones for regear to 4.56
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Want to sell me your d44 rear?
BisleyWrangler, have sent you a PM.
Bisley gets first dibs, if he passes up on it, anyone else want to buy a D44? 3.07, Trakloc, done 90k. Is a complete rear end. Has axle shafts, hubs, rear brakes etc all still attached.
Was thinking £250 plus delivery. But no real idea what it's worth other than I paid 350 for my 3.73 rear. Please let me know if this is ridiculously high/low. Could do with a quick sale.
Will give Bisley a couple of days to confirm before offering it out to everyone else. If you want it though, let me know and I'll give you a shout if Bisley isn't interested.
The D30 is also up for grabs. I'm taking the axle shafts and UJs, but the rest is free to whoever can collect. If no interest it'll go to the scrap man, as I've no where to keep it and the Mrs is moaning.
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Finally!! Got the build sheet for the TJ
Vehicle Description
Model Year 2000
Body Model TJ U H 77
Color PYHA- Solar Yellow Clear Coat
ISD 11/09/2000
Open Recalls No
Engine EPE- 2.5L I4 Power Tech Engine
Transmission DDQ- 5-Speed Manual Transmission
Selling Dealer 13589
Warranty Covg. Code 188
*K5 Cloth High-Back Bucket Seats
-AZ Agate
ABBA European Equipment Group
ABES Export Equipment Group
ABUA United Kingdom Equipment Group
ADC Convenience Group
APAS Monotone Paint
A28P 2.5L Engine(EPE)/5Spd M/T AS72(DDQ)
BAHS 81 Amp Alternator
BCDS 500 Amp Maintenance Free Battery
BGAS Power Front Disc/Rear Drum Brakes
CADP High Back Bucket Seats
CDBS Reclining Front Seats
CFMS Rear Folding Seat
CGGS Traveling Inboard Seat Belt Buckle
CGWS Next Generation Front Air Bags**
CKES Front Seat Area Carpet
CKFS Rear Seat/Wheelhouse/Cargo Carpet
CKTS Cargo Tie Down Loops
CLCS Front Floor Mats
CLSS Sport Bar w/Rear Padding
CSAP Spare Tire Cover
CUFS Full Length Floor Console
DBBC All Manual Transmissions
DDQ 5-Speed Manual Transmission
DHNS Command-Trac Part Time 4WD System
DJJS Dana 30/186MM Front Axle
DMES 3.73 Rear Axle Ratio
DRKS Heavy Duty Dana 44 Rear Axle
DSAP Trac-Lok Differential Rear Axle
EAAC All Engines
EPE 2.5L I4 Power Tech Engine
GBBS Tinted Windshield Glass
GCBP Light Tint Front Door Windows
GCF Full Metal Doors w/Roll-up Windows
GREP Left Mirror
GSEP Right Mirror
GTES Manual Mirrors
GVAC All Vehicles W/O Power Mirrors
GXXS Sentry Key Theft Deterrent System
HCDS Heater w/Instrument Pnl Ventilation
JAYS Instrument Cluster w/Tach
JCKP 110 MPH Primary Speedometer
JHAP Var Intermittent Windshield Wipers
JJAS Cigar Lighter
JJHS Single High Note Horn
JJJS 12V Auxiliary Power Outlet
JKAS Locking Glove Box
JKLA Headlamp Leveling System
KFRS Dark Silver Metallic - Badge - Sport
KWRS DARK SILVER Metallic - Badge - Jeep,
KXRS DARK SILVER Metallic - Badge - Wrang
K5ZS EXTERIOR COMPONENT COLOR
LBBP Courtesy Lamps
LDAP Underhood Lamp
LMJS Halogen ECE Headlamps
LPGS Rear Fog Lamps
LPSS CHMSL Lamp
MBAS Black Front Bumper
MB5S Black Rear Bumper
MCHS Bumper Extensions
MFPS Chrome Headlamp Bezels
MFRS Black Front Frame Overlay
MFTS Body Color Grille
MWBS Sport Bar w/Side Padding
NAC European II Emissions
NBKS EVAP Control System
NF1S 19 Gallon Fuel Tank
PYHA Solar Yellow Clear Coat
QYHS Solar Yellow Clear Coat
RA8S Delete Radio
RCDS 4 Speakers
RDDS Fixed Long Mast Antenna
SBAS Power Steering
SCES 2-Spoke Soft Feel Steering Wheel
SDAS Normal Duty Suspension
SHAS Front Stabilizer Bar
SHCS Rear Stabilizer Bar
SUAP Tilt Steering Column
TBBS Full Size Spare Tire
TBRS Outside Tire Carrier
TMSS P215/75R15 RBL Wrangler AT Tires
TZAS Goodyear Brand Tires
VJXA Black Easy Folding Soft Top
WJ5S 15X7.0 Full-Face Steel Wheels
WKBP Matching Spare Wheel
WLYC All Steel Wheels
XCYS Upgraded OBD-II Connectors
XEES Fuel Tank Skid Plate Shield
XEFS Transfer Case Skid Plate Shield
XEVS Tow Eye Brackets
XJFS Tethered Fuel Filler Cap
XPFS Protective Coating and Remover
YABS Build To Export Mkt. Specifications
YG7A 2 Additional Gallons of Gas
ZAVP Spring - Left Rear
ZBDP Spring - Left Front
ZNVP Spring - Right Rear
ZPEP Spring - Right Front
Z5BS GVW Rating - 4450#
0Z8A FAM: TJ TRACKING: 90726J05 MY:2000
00BA FAM: TJ TRACKING: 90915J05 MY:2000
00KA FAM: TJ TRACKING: 91217J10 MY:2000
1AUS Export Homologated
106S Zone 06-Export
2TDA Customer Preferred Package 2TD
23D Customer Preferred Package 23D
3D2A Intl. Price Protection B
3HGA Coso Wt. & D.M.
3HMA Coso Spbr Not Required
3HQA Market Homologation
3HWA Export Ocean Freight
3HZA Export Insurance
4ALA 1NTL 37 DAY SCHEDULE
4HB Special Scheduling Condition II
4HC Special Scheduling Condition III
4XTA Delete Domestic Warranty Manual
4YBA Export Option Requirements
5I9S Right Hand Drive (RHD)
6CTP Certificate of Conformance
6EMP European E Mark Label
6MPP Manufacturer Body Plate
6Z2 Paint Order Code
8CNA United Kingdom Country Code
895A EMEA Region (Europe)
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That confirms 3.73s for UK 2.5 TJs then. I wonder why they got 4.10s in the U. S?
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Maybe the spec of your,2000 engine,produced,more,torque,than the earlier version with 1 coil not later plug on coil and they were chasing the mpg ?????
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1997 2.5 tj had 3.73 as well.
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Build sheet for my 2003 4.0 TJ says 3.07...