ECODIESEL DIFF RE-GEARING

[AC77]

Hello, everyone, has anyone upgraded their diff's ? how does it feel ?
any daily drivers that can chime in ? do you feel a bit more torque from stop to take off ?

4.10's ? for daily some light trailing/off roading , no rock crawling
thanks

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[Adv_aw8s]

We regeared to 4.56's on 37's. I think it's perfect and glad we did it. We also live at elevation in Colorado and tow a trailer pretty frequently. I was on stock gearing for prob 10k miles, lifted on 37's before the regear. I know a lot of people say no regear is needed but I'd always recommend a regear, diesel or not!

 

[AC77]

We regeared to 4.56's on 37's. I think it's perfect and glad we did it. We also live at elevation in Colorado and tow a trailer pretty frequently. I was on stock gearing for prob 10k miles, lifted on 37's before the regear. I know a lot of people say no regear is needed but I'd always recommend a regear, diesel or not!

i see why you did it, and i agree with you , im in Los Angeles, lots of freeway and street driving, only uphill is the freeway i take to and from work and its a 15 mile uphill , torque is fine on the Diesel, im happy with it, i think ive gotten used to the power/feel lol .. and i know Diesels in general like to stay low on the RPM range, they are not meant to be high revving , but wanted to see if anyone has done one step above the stock 3.73 's ... thanks for your input on this

 

[grimmjeeper]

Going from 3.73 to 4.10 is a less than 10% difference. You won't notice it as much as you think you will. Still, 4.10 is probably the best ratio for 37s in the diesel.

Having gone from 35s (best size with 3.73 gears and the diesel) to 37s, I did notice a slight change but not enough to want to spend the money to swap out gears. Even living at 6000 feet and Jeeping at 10,000+.

If I hadn't already done some upgrades on my axles, I would look for some 4.10 Rubicon take offs and swap them in, then sell my axles to someone else. That would be a lot cheaper than regearing in the end.

If I was towing, I would swap to 4.56 and live with being slightly over geared.

 

[AC77]

Going from 3.73 to 4.10 is a less than 10% difference. You won't notice it as much as you think you will. Still, 4.10 is probably the best ratio for 37s in the diesel.

Having gone from 35s (best size with 3.73 gears and the diesel) to 37s, I did notice a slight change but not enough to want to spend the money to swap out gears. Even living at 6000 feet and Jeeping at 10,000+.

If I hadn't already done some upgrades on my axles, I would look for some 4.10 Rubicon take offs and swap them in, then sell my axles to someone else. That would be a lot cheaper than regearing in the end.

If I was towing, I would swap to 4.56 and live with being slightly over geared.

Ok. Nice. And good idea on the Rubicons. Still simmering Thanks bro

 

[Ratbert]

What size tires? That's a somewhat critical detail that's missing.

4.56s feel about right to me with 37s and lots of weight. I can't really tell you how it'll differ since that's basically (4.63s actually) what it came with new.

 

[AC77]

What size tires? That's a somewhat critical detail that's missing.

4.56s feel about right to me with 37s and lots of weight. I can't really tell you how it'll differ since that's basically (4.63s actually) what it came with new.

I’m on 20x33. Will be going to 35’s once tires are do. Next year

 

[grimmjeeper]

I’m on 20x33. Will be going to 35’s once tires are do. Next year

Honestly, 3.73 is best for 35s.

It's my guess the only reason they didn't put 3.45s in the diesel was because the front M210 doesn't have them available. And the M186 isn't capable of handling the torque.

I ran 35s with the stock 3.73s for a couple of years and was very happy with the combo. I'd say try the bigger tires for a while before swapping gears. See how you like it before spending all the money.

The low end torque of the diesel makes a lot of difference. The lack of low end torque on the 3.6, especially when paired with the manual, makes for significantly different gearing choices.

 

[Max Headroom]

Hello, everyone, has anyone upgraded their diff's ? how does it feel ?
any daily drivers that can chime in ? do you feel a bit more torque from stop to take off ?

4.10's ? for daily some light trailing/off roading , no rock crawling
thanks

I'm daily driving on 35's with stock gearing, at about 5,000 ft altitude, and find the factory ecodiesel gearing just about right.

 

[Mr. Curti]

I have to agree with the previous comments. If you are going to go from 33 to 35’s, I would leave the gear ratio at the 3.73’s.

If you feel that you need a little more punch, consider a Banks pedalmonster. Or whatever throttle system you feel comfortable with. I recommend Banks because I have it and it works perfectly for my application.

Also get the Z Automotive Tazer. Now if you do not plan on doing anything beyond the 35’s, the Lite version will serve you well and save you a couple bucks. But if you plan on doing more than just 35’s, get the Mini version because it’s set up for more modifications when that time comes.

 

[Duc Hunter]

I don't disagree with the consensus here. I’ve always been curious though….. stock diesel sports had a 245/75/17 tire and 3.73gearing. If Jeep intended that to be the “right” gear ratio for economy etc, then for 35’s we would want 4.15 (so 4.10), and 38’s would want 4.50 (so 4.56). If we think Jeep engineered the diesel gearing for the Rubicon’s though, then 35’s would want a 3.99, and 37’s would want 4.33. Just depends on which tire spec they designed the diesel to.

Personally I think the diesel is good for 33’s easily, 35’s for flat landers who aren’t rock crawling or towing, as many here have proven.

 

[Deleted User 38384]

Going from 3.73 to 4.10 is a less than 10% difference. You won't notice it as much as you think you will. Still, 4.10 is probably the best ratio for 37s in the diesel.

Having gone from 35s (best size with 3.73 gears and the diesel) to 37s, I did notice a slight change but not enough to want to spend the money to swap out gears. Even living at 6000 feet and Jeeping at 10,000+.

If I hadn't already done some upgrades on my axles, I would look for some 4.10 Rubicon take offs and swap them in, then sell my axles to someone else. That would be a lot cheaper than regearing in the end.

If I was towing, I would swap to 4.56 and live with being slightly over geared.

I'm with this guy, running 37s, there's not as much get up and go with the 3.73 gearing, but, it's not a big enough downfall to spend thousands of dollars re-gearing.

Still plenty of low end torque when I need it (for off-roading), and I don't tow so that helps.

 

[zouch]

i went to 35s on the stock gearing, and it wasn't bad, though 4.10s would have been numerically nearly perfect.
when i went to 37s, i hated it until i was able to get it regeared and went to 4.56s which were numerically a little deep for 37s but would be nearly numerically perfect for 39s. 4.56s also help compensate for the extra weight and wind resistance of the larger tires and lift.

i feel 'driveability' is much improved over the stock gearing, and now i have all my fluids (cooling, lubrication and transmission) moving at at least the rates they were designed to be at for any given load.

 

[Ratbert]

i went to 35s on the stock gearing, and it wasn't bad, though 4.10s would have been numerically nearly perfect.
when i went to 37s, i hated it until i was able to get it regeared and went to 4.56s which were numerically a little deep for 37s but would be nearly numerically perfect for 39s. 4.56s also help compensate for the extra weight and wind resistance of the larger tires and lift.

i feel 'driveability' is much improved over the stock gearing, and now i have all my fluids (cooling, lubrication and transmission) moving at at least the rates they were designed to be at for any given load.

What do you mean by numerically perfect? Are you under the impression that what's chosen is more than a crapload of compromises that includes what suppliers happen to be producing at a reasonable cost?

 

[AC77]

I don't disagree with the consensus here. I’ve always been curious though….. stock diesel sports had a 245/75/17 tire And 3.73. If Jeep intended that to be the “right” gear ratio for economy etc then for 35’s we would want 4.15 (so 4.10), and 38’s would want 4.50 (so 4.56). If we think Jeep engineered the diesel gearing for the Rubicon’s though, then 35’s would want a 3.99, and 37’s would want 4.33. Just depends on which tire spec they designed the diesel to.

Personally I think the diesel is good for 33’s easily, 35’s for flat landers who aren’t rock crawling or towing, as many here have proven.

Thanks for this breakdown, my Sahara altitude came stock with 18's

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