|11-03-2011 04:23 AM|
thanks for all your tips! I will go to 4.88...
|11-02-2011 10:44 AM|
You would only be turning over 2400 rpms with your particular 4-speed automatic transmission at 70 mph with 33" tires and 4.88. Your 4-speed's overdrive has an extremely steep .69 overdrive ratio which is why I keep telling you that you need that 4.88 axle ratio to overcome it.
At 60 mph, as you asked about, you'd only be turning over 2057 rpms with 4.88.
One last comment that might help. After my '97 TJ was stolen, I bought my present '04 from a friend and it came with the same transmission you have, 35" tires, and 4.88 gearing. The engine lugs (rpms are too low) so I keep having to turn the overdrive off. With my 35" tires and 4-speed automatic, I'd be much happier with 5.13 or 5.38... 4.88 is not enough gear for 35" tires with this particular transmission. My present 4.88 would be ideal for 33" tires however. The previous owner admitted he screwed up by only installing 4.88 gearing with 35" tires, 5.13 or, and likely better, 5.38 would have been ideal.
|11-02-2011 05:50 AM|
|11-02-2011 04:36 AM|
|Northwest4x4||33s are not that big and 33s wont be breaking anything...|
|11-02-2011 04:20 AM|
|ckalogris||what setup do you currently run? will I be able to go on highway with 4.88, or I will see 3,000rpm at 60mph?|
|11-01-2011 11:16 AM|
|11-01-2011 11:14 AM|
|ckalogris||What about that I was told that 4.88 is very small and sometimes breaks under pressure?|
|11-01-2011 11:09 AM|
|11-01-2011 11:03 AM|
|ckalogris||From what I have been reading, I have seen that 4.56 is the ultimate for me, since I get on the highway 2-3 weekends per month (travelling @ 60mph). Moreover I was told that 4.88 is very small and sometimes is destroyed under pressure. 285/75/16 is approximately 32.5", so my rpm will be a little bit higher than that @ the same set up and 33" (that is why I also want to know about 4.10).|
|11-01-2011 10:52 AM|
|Jerry Bransford||Ok, that tire size is equivilient to 33" which means, because you have the 4-speed which has a very high overdrive ratio, your axles should be regeared to 4.88. 4.56 would not raise the rpms enough to let the engine run without lugging. You'd likely get worse mpg with 4.56 and you'd definitely not like how it drove with 4.56... you'd be constantly switching the overdrive off.|
|11-01-2011 10:43 AM|
you have a point there!
it's 2005, with an OD
|11-01-2011 10:38 AM|
|Jerry Bransford||What model year TJ do you have? Through 2002 the auto was a 3-speed which became a 4-speed in 2004.|
|11-01-2011 10:37 AM|
TJ with 285/75/16, 4.56 or 4.10 and A/T
Does anyone have this setup? Can you tell me the rpm you get at 60mph? Any pics?