As always, which transmission? Either option, it won't be 4.56. 37s are questionable with stock axles on a couple fronts.
I run Motive gears and have had no problems. But if you are needing 5.13, then you are looking at Revolution or Yukon.
Should I stay with 4.56 gears?
- Thread starter Lilbomb
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As always, which transmission? Either option, it won't be 4.56. 37s are questionable with stock axles on a couple fronts.
I run Motive gears and have had no problems. But if you are needing 5.13, then you are looking at Revolution or Yukon.
Doing the 'math' usually means finding the ratio restore the engine rpms back to what they were with the smaller tires. That produces misleading results, 4.23 would have produced insufficient rpms to restore the power loss from 35" tires. It takes more rpms to turn larger diameter tires than it did to turn smaller tires. It takes bigger muscles to lift bigger weights. 4.88 is what you want, 4.56 would produce frustrating results that would force you to constantly be downshifting from 5th to 4th to keep up with traffic or even get up very minor grades that shouldn't normally require downshifting.
Doing the 'math' usually means finding the ratio restore the engine rpms back to what they were with the smaller tires. That produces misleading results, 4.23 would have produced insufficient rpms to restore the power loss from 35" tires. It takes more rpms to turn larger diameter tires than it did to turn smaller tires. It takes bigger muscles to lift bigger weights. 4.88 is what you want, 4.56 would produce frustrating results that would force you to constantly be downshifting from 5th to 4th to keep up with traffic or even get up very minor grades that shouldn't normally require downshifting.
Thank you Jerry, I always see you adding comments on here and have much respect for your input!
I'm in an automatic 4.0 with the Over Drive button. My cousin has similar set up (XJ) with 4.56's minus the OD button and suggested 4.88's because hills are a little tough for him. I was leaning towards the 4.88's but thought I'd get your guys opinion first.
These are two different transmissions. For 35s on the 42rle, you want 5.38. but your Dana 30 front will only allow 5.13.
It's also debatable if 4.88 would be deep enough on your cousin's XJ.
Whoops I thought you had a 5-speed manual transmission. Ignore my advice to regear to 4.88.
Your 4-speed automatic with the Overdrive button is a completely different beast, 4.88 is NOT enough gear for 35's. Your transmission's .69 Overdrive ratio drops the highway cruising rpms way too much for 4.88 to work well enough that you'd be happy with it. If you had a Rubicon I'd suggest 5.38 but since your front axle is a Dana 30 that means 5.13 is as low of a ratio as you can regear to. That's what I strongly suggest. Definitely go 5.13.
I bought my present '04 Rubicon with the same 4-speed automatic transmission used with 35" tires with 4.88 gears. It was an absolute dog on the highway, the engine lugged constantly. Mpg never even made it to 12 mpg. I was able to regear it to 5.38 last year and holy smoke, it fixed all the highway lugging issues and the mpg went up into the mid-14's. Make sure to go 5.13, don't make the mistake of only regearing to 4.88 as my TJ's previous owner did.
Thanks Jerry, I really appreciate the reply. It's a perspective I never really thought about. You all just saved me from a costly mistake!Doing the 'math' usually means finding the ratio restore the engine rpms back to what they were with the smaller tires. That produces misleading results, 4.23 would have produced insufficient rpms to restore the power loss from 35" tires. It takes more rpms to turn larger diameter tires than it did to turn smaller tires. It takes bigger muscles to lift bigger weights. 4.88 is what you want, 4.56 would produce frustrating results that would force you to constantly be downshifting from 5th to 4th to keep up with traffic or even get up very minor grades that shouldn't normally require downshifting.
Wow, I never even considered 5.13's. Most people said 4.56 and some 4.88 but you and JJVW would be the first to suggest 5.13. Someone told me 4.88's would not help MPG and my rpms's would be a little high. Thank you guys
So glad you posted this question, good luck with the build
It really doesn't matter. Pick the supplier with the best customer service and best warranty.
The dirty little secret in the Jeep TJ Wrangler aftermarket chromoly axle industry is that with the sole exception of the more expensive Revolution Gear & Axle "made in U.S.A." axle shafts for the Dana 30 and Dana 44, all TJ Wrangler aftermarket chromoly axles are sourced from the same short list of foundries in India.
My advice for re-gearing and axle replacement is to let the shop that is doing the work supply the parts. Trying to save a dollar or two by purchasing direct from some online source is a false economy. If the shop is willing to install customer supplied parts at all, and most good shops won't, there will be no warranty on the labor to replace any part that turns out to be defective.
I’m getting new gears this week ....if I didn’t trust the shop to supply the right gears , I wouldn’t trust them to do the work.
These guys set rigs up ready for battle. They will put Spicer gears in.
I’m a contractor, and I turn down jobs fast when people buy material that is problematic or not complete , like tile without trim pieces.
I’d at least have get the shops ok ahead .
If you are re gearing yourself, none of that matters ....,knowing how does though.
These guys set rigs up ready for battle. They will put Spicer gears in.
I’m a contractor, and I turn down jobs fast when people buy material that is problematic or not complete , like tile without trim pieces.
I’d at least have get the shops ok ahead .
If you are re gearing yourself, none of that matters ....,knowing how does though.
Thanks for the input, I’m not sure who’s going to do them yet. I’m still thinking about the 5.13 recommendation.
You are on the right track and you are smart to make sure you get the ratio where it needs to be.
In my opinion gears are just an absolute must.... Far too many people don't want to face the reality of what the engine is capable of doing and what the oversized tires do..
People will spend countless dollars on all kinds of modifications and accessories and ignore the one thing that makes the Jeep more capable... And in my opinion it even makes the Jeep safer because you're able to contend with traffic at the speed you should be able to.
Since you will have a shop install your new gears, make sure to let them provide ALL of the parts required. Gears, master install kits, and the lubricants. If you provide the parts and something goes wrong during or after the gear installation, guess what's going to be blamed... the parts you provided. And the shop's warranty would only cover their labor, not the parts you provided. You'd be stuck in the middle with the shop blaming the parts you provided and the dealer you bought the parts from blaming the installer. And when there are problems during or after a gear installation, it's usually the installer's fault... not the parts. And trust me, not all gear installations go right the first time.
You can request they use a certain brand of gear but if they balk and want to use a brand they're more comfortable with, go along with them. My personal first choice of gear brand is Revolution Gear since their gears are guaranteed made by Circle K in S. Korea who currently makes the very best quality gears. Some other gear companies often use Circle K too but not always like Revolution Gear does.
You can request they use a certain brand of gear but if they balk and want to use a brand they're more comfortable with, go along with them. My personal first choice of gear brand is Revolution Gear since their gears are guaranteed made by Circle K in S. Korea who currently makes the very best quality gears. Some other gear companies often use Circle K too but not always like Revolution Gear does.
Thank you guys, I’ve got some quotes from shops but not inquired about
You're right, theres so many other mods I still want to do. But I figured gearing it right and spending the money will put less stress on the engine and I plan on keeping it for a long time. I've had over 40 vehicles titled (not a dealer) in my name but this is the first one that I've dumped serious money into and longest vehicle I've ever owned. What set up are you running?
You're right, theres so many other mods I still want to do. But I figured gearing it right and spending the money will put less stress on the engine and I plan on keeping it for a long time. I've had over 40 vehicles titled (not a dealer) in my name but this is the first one that I've dumped serious money into and longest vehicle I've ever owned. What set up are you running?
Actually Jerry, I've got some quotes from shops and have a buddy that took it to a guy in his club who did it in the garage. My buddy trusted him so I'm considering going that route too.
To give you guys an idea, Brothers 4x4 in Montclair told me $1600, Savvy Offload in Corona $1300. This is labor and 4.88 gears. So, I'm still shopping around.
Talk to Allen at Allen's Off-Road. He can get you Revolution gears and I'm sure at a better deal shipped.