My '95 trooper seems to be pulling some high RPM numbers at 70MPH. I see,m to be running about 2900 RPM at 70 w/ 285/75/16s. Speedo numbers have been adjusted for tire size. My '01 tunred much lower RPMs at same speed. I know that higher axle ration and OD made a difference. Just wondering wahts "normal".

I'm not really looking to change gears. RPM seem too high on the '95. Makes me wonder what gears are in the back. I know 4.56 is supposed to be there, but 2900RPM seems pretty high to be running 33s.

i'm not sure why 2900 rpm is considered high for 70mph. The highest speed limit i've seen in the US is 75, and with modern lubricants and computer aided design, engines should be better set for high rpm's than ever.

my gf's completely stock 97 VW golf 5 speed spun ~3100 rpm at 70mph. <img src="/forums/images/graemlins/kewl.gif" alt="" />

My '89 with 4.55's and 235/70-16's turns about 2900 at 70mph in O/D... in 3rd gear, it turns about 3500 @ 70mph.

My friend's Geo tracker 4x4 runs 5000 rpms at 75mph and seems very happy. Never downshifts for hills, guess it would hit 10000 rpms if it did <img src="/forums/images/graemlins/lol.gif" alt="" />.

With my AT if rpms are over 3k in OD it doesn't downshift at wide open throttle. If revs were higher dumb tranny 'puter would not waste revs downshifting at 75mph. I would really like to see a way to manually control OD.

I hope to be cruising at over 3k rpms this spring with 5.38s installed. In my Trooper if cruising rpm was over 4k then might be concerned, but not at 3k rpms.

What do you mean by manually control the O/D?
There is a lock out button on the shifter that allows you to lock it out... Unless I'm on open land, I always keep my OD turned off... it pulls the hills better and gets better gas mileage...

When you say 70 MPH do you mean what is says on the speedo or corrected speed? On my truck with 32s when the speedo says 70 MPH ( pushing 75 MPH in reality) it is around 2500 RPM.

At 70mph, my pickup with 4.56s and 33s and the 2.6 turns roughly 2500-2600 rpms in overdrive. A V6 will turn less rpms with the same exact setup.

Richard

On the 2.8L's although the trans is electronically controlled, it does not use the common (to imports) thumb clicky switch for o/d lockout but rather has a 4-forward-position shifter. 1-2-3-D. by throwing it down to 3, you've got forced 3rd gear at any sane speed. I never find that I have to do that though, as I find the kickdown to be near perfect for my driving style. Jill's XJ transmission has much more sluggish TCM software and I find myself manually selecting 3rd pretty frequently on that thing.