TJ speed after lift

[KrazyJeeper]

Ok, so if I put 33's on this Sahara how fast will I be able to go down the highway, not that I want to go fast, but I at least want to do the speed limit. In the 2.5 TJ I sold last year, I never reached fifth gear and never over 55 or so and that was with the pedal in the floor. Thanks, KJ

 

[LGR]

when i had my 6 cylinder TJ on 33s with 3.73 gears it wasn't that bad..picking up speed up hills never happened again, but if ya knock it back into 4th you can do alright. I don't think it'll be that bad

 

[KrazyJeeper]

LGR, thanks for the input, this one is an automatic and I guess I forgot to mention that. That is the reason why I am worried. I don't think it would be that bad if it was a stick, but with my knees nowadays, I am glad I got the auto. Thanks. KJ

 

[TwistedCU]

MY XJ had 32's with a 4 spd auto and 3.55 gearing and it would have no problem cruising at 80 mph.

What year is it? 3 speed or 4 speed auto? Most importantly what gears are in the axles?

 

[JeepMonkey]

My TJ has 6" lift and 33's runnin 4.10's and I rarely see 5th on the highway. It always seems to want to slow down so I just leave it in 4th. I'm sure I'm doing at least 65-70 unless it's really windy or a bad piece of road. I've also got a manual, but I would think with the 4spd auto you could kick it down to 3rd and motor right along.

 

[KrazyJeeper]

I know this question has been asked a thousand times but I can't seem to find the post. The Jeep is a 2000 Wrangler Sahara auto 3 speed, so how do I know what axles I have? Thanks, KJ

 

[JeepMonkey]

Well, if you're talkin about gear ratios, I've heard that you can get an estimate of the size by driving at 70mph in 3rd gear and reading what the tach says. For instance if it's just over 3000rpm then you probably have a 3.08 and if it's over 4000rpm then you have a 4.10. I don't know if this is accurate, but it stands true on mine. One caveat, though, you have to have the original tire size or be pretty close. Other then that you can lift the rear end, mark the driveshaft and have someone turn the wheel while you count how many times the mark spins around for one revolution of the wheel. I've never done that though and don't know exactly how to do it.

 

[Bounty__Hunter]

Look at the metal tag attached to two diff cover bolts, the first three digits will be the gear ratio. Should look like 3 07 or 3 55 or 3 73.

You'll lose a lot of performance if you have 3.07, but the 4.0L and auto transmission will compensate for it. If you have the 3.73 (which most jeeps with your drivetrain have) you'll be just fine with 33" tires, with a small loss in acceleration and top end.