I have a 2002 TJ II 4sp auto. With the way I drive I don't think my auto will last more than a few years. It's already a bit shakey. So when it does **** itself what are my options. Will a 5sp auto fit? I'd imagine it would involve a computer change as well to get it to work. How about the tip-tronic function, will the dash need to be changed to show 5 gears? I would also like to keep the higher final drive ratio of the 4sp, to make for quiet and efficient crusing.

Has anyone done this before? I don't want a manual either. This is the first auto car I've owned and I'm not going back. The reason I want a 5sp is for the lower first gear. With the 4sp it's a bit slow till you get upto 40km/h then it really takes off. The Falcons we got at work don't get going till they hit 60km/h, whats the good of having 190kw if you can't get to it at the traffic lights?

Sorry I cant answer your question about if a 5spd auto would fit but I can tell you from personal experience that they are not that reliable, IMO I would go a manual conversion (just an opinion) but if you do decide to get the auto throw a shift kit in and also reinforce the pins in the shafts.

With the amount of work involved, it'd probably be worth either buying a donor car, and strip everything you need, or, the better option: buy a car that already has a 5 speed box.

As bean machine said, the 5 speed can be hit and miss. The box in my parents Verada is utterly terrible.

You would have to change the dash and the ECU, as well as the messy business of changing the transmission. Hardly worth the effort - it would be more economic to simply buy a 5-sp auto car.

The 5-sp auto is a great transmission. My only criticism of it is the insane insistence on changing up to 5th gear at less than 60 kph.

I was only going to do it if the 4sp broke.



The 5-sp auto is a great transmission. My only criticism of it is the insane insistence on changing up to 5th gear at less than 60 kph.

The 4sp changes into 4th just below 60kph. It's barely doing 1400rpm, but the 3.5l has heaps of torque to keep it going, even up decent hills. It won't change to 4th if your going up a hill or carting lots of weight (ie. people). Thats what makes this the only auto I actually like.

The 4sp changes into 4th just below 60kph. It's barely doing 1400rpm, but the 3.5l has heaps of torque to keep it going, even up decent hills. It won't change to 4th if your going up a hill or carting lots of weight (ie. people). Thats what makes this the only auto I actually like.

The 4-sp isn't as bad in this respect - at least 1400 rpm is allowing the engine to start breathing. The 5-sp has a very tall overdrive gearing of over 45 kph per 1000 rpm (in 5th gear). I have often seen it at barely 1200 rpm, up a hill, which is just 400 rpm above idle! Yes, I can kick it down, but this is not necessarily helpful if it then accelerates too quickly in 4th. In practice, I often change it manually into 4th or 3rd, but it's a minor irritation noted by several "Tippy" drivers on this forum.