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How fast is it ok to go in 4wd? I have a 91 grand with select trac, and have driven 70-80 mph in 4 hi. Havent noticed any problem. I sometimes drive 50-60 with the part time 4wd drive in 4hi on the cherokee. Am I risking damage to anything?
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Go till ya can't go no mo...you're not hurting anything.
You're fine in 2WD or 4WD...just don't try freeway flying in LO range.
joe
"Don't mind me. I'm just here for the alibi" -
In high it's the same gearing as 2wd, but if you tried to drive fast in 4 lo, you'd have the rpms up so high you'd likely blow the engine shortly'84 Grand Wagoneer 360/727/229, 32" General ST's and 36" Swampers, 3" lift, TFI/Mallory 6AL, CS 144, Taurus fan, custom bumper, and custom 'bodywork'. Soon to have 6" lift
'79 Cherokee S 360/T15/D20, rusting away while I figure out what to do with it
'91 Final Edition GW in Spinnaker Blue!
My FSJ pics
FSJ Grille IdentificationComment
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Driving a part-time 4wd in 4hi on a high-traction surface is risking severe damage to the Tcase. The will be no differentiation between the front and rear axles. This can explode the case.
Full-time 4wd has a differential inside the Tcase to allow the front and rear axles to move at different speeds to avoid damage. Full-time cases have a "Lock" position for low traction situations. When out of such a situation, you return to regular 4wd.
Part-time cases mean just that. When in 4wd with a part-time case, the front and rear axles are locked together. Turn a corner and you're in trouble on a high-traction surface.N4ZYV
I ain't giving up. I've worked hard, it took me years to work my way to the bottom.
1998 Cherokee Sport (not maroon! Have history with maroon XJs)
1937 Chevy pickup (in progress)
1966 Mustang
1937 IH D2Comment
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I only use the part time 4hi on gravel or wet roads.Comment
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Speed is relative to gearing. For instance your Grand Wag in low range is like my FC150 in 4 high. The FC has 5.38 gears with which the ads for it say will allow "you to cruise effortlessly at top legal speeds" Of course, your top legal speeds must be 45 mph or lower. With the gearing in your GW you could probably could run the same speed at the same RPM in low range.65 wag. with a bunch of stuff done and more happening.<br /><br />\"If the local junkyard calls you for Jeep parts, you might be a redneck\".... and yes they do!Comment
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SelecTrac is either going to be an NP228 (86) or NP229 (all other years for SelecTrac). It has a limited slip or open "differential" in the case to allow driving on pavement aka full time operation but can also run in 2wd. I doubt you have to worry about hwy speeds with full-time mode of the NP228/9.
MichaelBroken Photobucket image in my post? PM me.
1986 Grand Wagoneer "Troubled Child" ? tc.wagoneer.org ? Facebook ? KØFSJ
Stock 360, TBI, 727 with TransGo, NP208, 4" Skyjacker, 33" BFG MT, WT Axles, Lock Right & ARB, OBAComment
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Michael covers the Grand Wagoneer.
This is the one that has me worried:
"I sometimes drive 50-60 with the part time 4wd drive in 4hi on the cherokee. Am I risking damage to anything?"N4ZYV
I ain't giving up. I've worked hard, it took me years to work my way to the bottom.
1998 Cherokee Sport (not maroon! Have history with maroon XJs)
1937 Chevy pickup (in progress)
1966 Mustang
1937 IH D2Comment
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