Calgary Jeep Association
4x4 Related Groups => Tech Talk => Topic started by: jeeptastic on August 06, 2009, 11:42:35 AM
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Hi Everyone. I am new to this site and very new to 4X4ing. The few times that I have made it out I have had the best time ever and I am really looking forward to going out more. Do you have monthly meetings and is everyone welcome?
My question is my rear differential went on my Jeep last weekend and I have thought about re-gearing my jeep for a couple years now. With the research that I have done I have found that the standard gear ratio in my Jeep is a 373. Now that I have to replace the rear differential I thought I would change the gear ratio too. I am looking at changing to a 410 gear ratio (with trac-locs this seems like a good option to have... do you agree?) both front and rear differentials.
My Jeep is a 1998 TJ with a 4.5 inch Rubicon Express Lift and I have 33" tires on it. I hardly use my fifth gear anymore. So will changing to a 410 ratio help me out?
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yes we have monthly meetings, everyone welcome. just have to check our FAQ section.
some will say 4.10 is enough but most will say not. i had 4.10 on 33 and it wasn't very nice at all, especially with highway and hills.
4.56 seems pretty good driving friends jeep, feels pretty close to my 35's w/ 4.88
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4.10s and 33s is decent but 4.56s would be better and if ever plan to go to a bigger tire, you might want to consider 4.88s. I am guessing you have a D44 in the rear?
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I dont have a D44 in the rear. Everything is stock. Does that matter? Like I say I am new to this and I am learning as I go.
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4:56s and don't look back.
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If I put 456 on the jeep will my rpm's be huge? I use my jeep as a daily driver as well and really enjoy taking it to BC in the summers. Will that matter?
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4.56's would be the way to go if you will stay on 33's for all time. If 35's are being considered down the road, then 4.88's are optimal.
I do a lot of the gear work for the club. PM for info and options.
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If I put 456 on the jeep will my rpm's be huge? I use my jeep as a daily driver as well and really enjoy taking it to BC in the summers. Will that matter?
Here is a gear ratio calculator
http://www.ringpinion.com/Calc_RPM.aspx
Miles per hour.
4.56 and 33's is 2100rpm at 60mph in 5th gear.
Anything between 2100-2700 at highway speeds if favorable for the 4 litre. Lugging them causes frequent shifting and poor mileage.
hth
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If I put 456 on the jeep will my rpm's be huge? I use my jeep as a daily driver as well and really enjoy taking it to BC in the summers. Will that matter?
456 & 33" will be good. I have 4:88 and large size 33" tires RPM in 5th at 100KM is 2700. I like it for towing. Yours should be lower than that. You will like the power for climbing hills.
Are you planing any other upgrades if you are running a Dana 35: truss, upgraded axcel shafts, c-clip eliminator kit? Some things to think about and price out.
Yes, talk to Bnine he can give you all the options. He has my d35 in for an upgrade right now ;D
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I've heard it said that 4:10's are optimal for 33's, but with the heavier weight of aftermarket tires,ie 33's, and rims, plus the other armor we often have on our rigs that 4:56's are better to compensate. Something to think about. Some people who get 4:10's say they wish they would have gotten 4:56's. People with 4:56's will never say they wish they had 4:10's.
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If I put 456 on the jeep will my rpm's be huge? I use my jeep as a daily driver as well and really enjoy taking it to BC in the summers. Will that matter?
think of it this way; right now you have it pinned in 4th on the highway. with 4:10s you'll be around stock. 4:56s will be the same as you are right now, except you'll be in 5th gear instead of 4th, and if you ever put the jeep in 4low and wheel. you will LOVE having the reduction.
i have 4:56s with 36s right now. i wish i had 5.13s.................
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haha I dont think I will ever be one of those guys who wish they had got the gears that give less power.
Are those options and upgrades good things to do while I am down with this differential problem or can I keep them in mind and pick away at them after I pay off this gear upgrade?
After reading all of the comments I called Modern Motors and they told me that for running 33" tires 4:56 is the way to go unless I am planning on going bigger down the road they then suggested 4:88. They also said with 4:56's that I will be running about 500rpm's higher and going with 4:56 I will gain my 5th gear back in the Jeep. They also said with going to 4:56 I will get better city fuel economy. Not much but I will see a difference. Which is always a bonus. haha
So if I do the 4:56 gear ratio and then decide to change to 35" tires down the road I will probably have a lack of power and same poblems that I am having now with 3:73 gear ratio and 33" tires am I right?
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So if I do the 4:56 gear ratio and then decide to change to 35" tires down the road I will probably have a lack of power and same poblems that I am having now with 3:73 gear ratio and 33" tires am I right?
A few years ago 4.56s were the gears to run with 35s but now a lot of people are going as lower as then can because offroading has changed to more crawler type. 35s and 4.56s will work fine. It will be like running 4.10s with 33s.
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Thank you everyone for all of your help.
When I get trac-loc's how does that work? Also is it possible to only have the two rear wheel working or will all four wheels be spinning if I get that trac-loc?
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Dont spend money on trac locs. That is the stock jeep limeted slip, and while its "okay" in a stock vehicle, it isnt something you would spend money on.
Sahara's jeep is at my garage right now getting gears and lockers. Another member has his in this weekend.
If you would like get a rundown on gears and drivetrain from some of the club members, feel free to stop by one night.
Cost you Tims for the crew. Call first and take the coffee order ;)
I will pm you my number.
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I just had my TJ (4.0L, 5 spd, 33's, D30 & D35) at Bnine's for 4.56 gears, Elockers, super 30, super 35, truss & c-clip eliminators.
I think 33's and 4.56 gears are the perfect offroad and/or towing combo. I can actually gain speed in 5th on a slight incline or with a bit of a head wind... whereas before I was either losing speed in 4th or reving like crazy and gaining too much speed in 3rd. Prior to the gear change... I never used 5th at all.
I haven't GPS'd my speed yet... but judging by the flow of traffic... I am about 2400RPM, in fifth gear and doing +/- 110KPH.
As far as modifying your Dana 35 or not... do a Utube search and see what happens when you break an axle on the 35... it's pretty interesting to say the least. I don't want to fear monger ya into spending a bunch of cash or keep ya from wheelin... just be aware of what could happen if you are running a "risky combo" and do "the wrong thing" to your "turdy five". I am sure someone would give ya a lift back to town... but fixing your Jeep in the bush is a whole different deal :o
Anyway... many ways to upgrade and/or change out your D35 (s0me cheap... some not so cheap)... but maybe a quick topic search and/or new thread may be in order first?
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I asked everyone about Gears last week and today I had another question for everybody.
If I am looking at putting ELockers in my front differential what would you recomend putting in the rear differential? Would you put Elockers in the rear as well or would you have the option to put in a Limited Slip in the back?
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If I am looking at putting ELockers in my front differential what would you recomend putting in the rear differential? Would you put Elockers in the rear as well or would you have the option to put in a Limited Slip in the back?
If you are going to the trouble of getting new gears, I would recommend going with a locker instead of a limited slip in the rear. Detroits are good if you don't want to go with a selectable locker, but I like ARBs
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This response is a bit late, but I had built an excel spreadsheet (while dreaming about new driveline parts) that allows you to plug in all the various parameters (transmission ratios, T-Case ratio, Diff Ratio and tire Diameter) so you can view much of the critical info for picking new gear ratios (i.e. crawl ratio, speed at RPM and RPM at 100kph). I'm kinda new, and I'm not sure how or if I can post a file to this Forum thread, but if anyone wants this spreadsheet I can certainley e-mail it.