Join Date: Aug 2001
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Re: 4.88\'s in a 97 TJ 4cyl
If it is a 4 dinger then and you have the stock axel in the back, it is a D35 (I am assuming that you have the stock rear) The 35 doesn't have very much room in there for tall gears, when you get up to 4.56's and 4.88's then gear teeth get smaller, the ring gets thinner, and the pinion gets smaller. When dealing with pieces of metal... smaller means weaker. And that is probably what the guy was telling you, they don't recomend them because they are weaker.
NOW, for you, who say that the jeep is on the road most of the time, and that you have the 2.5L and not the 4.0 I would tend to believe that your axels will hold up fine. As long as you are not dumping the clutch at 3-4K.
I am not sure if the TJ used a reverse R front 30, I know the YJ's did and that is a pretty strong unit. It should hold better than the rear.
As a general rule, if you jeep came from the factory with 27in tires, and 4.10 gears. Then if you run 33" a 4.56 will return you to factory rpm range, and 35-36 will be just about right with 4.88's
On an unrelated note, if you decide to regear, let me know I have a D30R, and D35 instal kits that have never even been out of the box, still shrink wrapped. They have been collecting dust, if you want them I will send them to you for a great deal. (however they are for YJ 30/35, I am not sure if the TJ is the same.