Re-gear for more power?

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Mike Hurlbatt

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Joined
Aug 16, 2017
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Perth, Western Australia, Australia
Hi Guys, i am new to the forum and have read some of the comments, but some of it is over my head. I have a question which I am hoping someone can point me in the right direction. I have 2002 TJ which is fitted with 33" tyres, but as far as I am aware the drive train is standard. My problem is that it has no low down power, so I wanted to regear it.
My question is what is the best way to do it, should I be looking at the transfer box, the gearbox or the diff ratios. My logic tells me transfer box, but then what gearing can be changed - if any.
 
Mike Hurlbatt said:
Hi Guys, i am new to the forum and have read some of the comments, but some of it is over my head. I have a question which I am hoping someone can point me in the right direction. I have 2002 TJ which is fitted with 33" tyres, but as far as I am aware the drive train is standard. My problem is that it has no low down power, so I wanted to regear it.
My question is what is the best way to do it, should I be looking at the transfer box, the gearbox or the diff ratios. My logic tells me transfer box, but then what gearing can be changed - if any.
Click to expand...
What engine do you have and is your TJ auto or manual? To gain back power lost by going with larger tires you will want to put new gears in your differential. Know the engine, transmission type and tire size helps to determine the gears needed.
 
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Engine is a straight 6 petrol, but I cant find a name plate to tell me exactly which engine it is. Gearbox is manual.
I do recall seeing a plate on the transmission, but will have to check details But its dark here so will have to check tomorrow. Tyres are 33 x 12.50 R 15LT Mudders.
 
4.56 gears in both axles would be a good match for your transmission and tire set up. That should restore the factory level power and rpm range.
 
Mike Hurlbatt said:
Thanks, that is a great help, much appreciated.
I will see what I can get locally, failing which I might be looking in the US.
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Doing the gears is most of the time best to leave up to a reputable shop. If you don't get them just right it will not be long before you are having to do them again. Plus it is on them to fix it if they don't get it right.
 
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The 4.56 recommendation was dead on. Just don't let some "expert" at the gear shop change your mind. A lot of them deal with dig diesel pickups , and don't realize that the Jeep 4.0 needs to spin a little more. A friend or mine did just that and let the shop talk him into 4.10,with 33,s and 5 speed. Not realizing the the Rubicon came with 4.10 and 31,s he made a $1300.00 mistake.
 
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I have decided to get on with the job and regear my axles to 4.56, but have been looking around for gear sets, and have come up with a couple of makes, Revolution is one, can anyone advise what to use and what to keep away from. I am going to do the job myself as I am a mechanic, and have plenty of experience with gearboxes and engine rebuilds although a fair while back, I have no problem with doing the diff.
 
I have been on Revolution website to order the gear sets , but cant figure out which one to order, can anyone advise please, I know the ratio, 4.56 but although I know my axles are Dana, there are about 10 different models ranging from Dana 28 to Dana 80, The rear axle has the following stamped on the cover plate DANA 42960 1 , 304 1, REV X, 03 20 00 - Jeep Wrangler 2002 model 4.0L, 5 Speed manual.
 
Is a shop doing the labor for you? (Or is it labour down under?) If so, will they install customer supplied parts? If they will, do they still warranty their labor?

In the U.S., the smart move for the consumer is to have the gear installation shop supply all of the parts even if it is willing to install parts one brings to them. Otherwise the consumer will likely be obligated to pay the labor charge for the shop to remove and reinstall a failed part even if the part is covered by a manufacturer's or seller's warranty.

Also, if despite your due diligence and advice from well meaning jeepers on the Internet you somehow end up with the wrong parts, it will be solely your problem and at your sole expense to cover any labor costs incurred. If, however, the gear shop orders the wrong parts it will be the gear shop that must bear all labor and additional costs involved.

Something to think about.
 
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Mike Hurlbatt said:
I have decided to get on with the job and regear my axles to 4.56, but have been looking around for gear sets, and have come up with a couple of makes, Revolution is one, can anyone advise what to use and what to keep away from. I am going to do the job myself as I am a mechanic, and have plenty of experience with gearboxes and engine rebuilds although a fair while back, I have no problem with doing the diff.
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Regearing an axle is nothing like working on engines or transmissions.
 
Rob5589 said:
The front will be a Dana 30 TJ version, the rear will be either a Dana 44 or Dana 35. The 35 has an oval cover and rubber oil fill plug, the 44 has squared off edges and a metal fill plug.
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L J said:
you should be Dana 30 front and Dana 44 rear

https://revolutiongear.com/shop/rev...ep-gear-packages/jeep-tj-d44d30-gear-package/

https://revolutiongear.com/shop/rev/koyo-gear-package/jeep-koyo-gear-package/jeep-tj-96-02-d44d30/
Click to expand...
L J said:
you should be Dana 30 front and Dana 44 rear

https://revolutiongear.com/shop/rev...ep-gear-packages/jeep-tj-d44d30-gear-package/

https://revolutiongear.com/shop/rev/koyo-gear-package/jeep-koyo-gear-package/jeep-tj-96-02-d44d30/
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Thanks LJ- Mine has the squared off cover with metal plug so it must be the Dana 44
 
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