How fast can you safely go in 4L? I have a 5 speed.



Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

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Justin - One Happy FTE Member

 

My gear reduction is 2.8 to 1
so if you were doing 56 in 4h.. it would be 20 in 4low
i would not exceed like 35 in 4low. Its not dangerous as far as going fast.. but why use 4low and run in overdrive ?


Rand

 

If I follow my calculations correctly, I would redline in top gear in 4L at about 30 mph. 4L is really designed for under 10 mph though.

The Law
1989 F-250 HD 4x4
460, C6, BW 13-56, Sterling 10.25" (4.10:1), Dana 44 HD (4.09:1), twin K&N's, no muffler, stock lo-flo cat, Bosch Platinum Plugs (0.060") MSD 6A and TFI Blaster Coil

 

[updated:LAST EDITED ON 03-Dec-02 AT 03:52 AM (EST)]How to calculate rpm in 4low vs rpm in 4hi or 2hi.

Use normal mph and rpm
then divide the amount by the reduction of the transfer case.

mine does 80mph at 3000 rpm.
so in 4low it would be 80/2.8 or 28.57mph
2.8 being my transfer case ratio (i think) on my 2002 ranger
according to my figures at 5000rpm that means my truck would be doing 47.6 mph. (there may be a rev limiter i dont know about)

but again why would you want to. 4low i wouldnt use with anything beside 1st or second gear. probably tops 20mph or so.
but you could go faster in it.

my first gear is like 3000rpm at mid twenties somewhere
so if we say 25mph at 3000 that becomes just under 9mph in 4low.

I take it everyone gets the picture..
If i have something wrong please by all means correct me :-)

btw I have the 5speed auto with 4.10 gears and 30.5in tires.


Rand

 

As fast as you want. The only difference in L & H is the fact that the planetaries in the t-case are spinning in L. But if you don't mind revving it up in 1st gear L, then you're not doing anything different to the planetary gears by revving it up in 5th gear L, and you're not doing anything different to the rest of the driveline than you do in 5th gear H. Taking it to top speed in L is no worse than top speed in H. Just don't use 4 with the hubs locked on dry pavement.

 

I think I was a little unclear when I asked the question. I know I can only go somewhere around 30 in 4L but I was just wondering if it hurts anything by doing that. Not saying i'm going to do it, but I was just curious I guess. My question was answered, sorry about the confusion.


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

Check out my Gallery for a look-see.


Justin - One Happy FTE Member

 

I don't like that way mine sounds past 20...I think there is something on the visor that says never exceed 25mph.

 

my ford manual says don't exceed 25 mph

 

I didn't see anything on my visor but thanks guys.


Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

Check out my Gallery for a look-see.


Justin - One Happy FTE Member

 

I sorta figured that.
Its common sense if you wanna go over 20 just use 1-2 gear in 4hi
vs winding it up in overdrive/4low

Rand

 

Why would anyone with common sense out there truck in 4L and see how fast they can go. 4L is made for extreme situations. If you want to go fast use 4H, that's what it's there for! Use your brain on this one!!!!

 

Relax man, I was just asking a simple question. The point isn't to go fast in 4L just for the sake of going fast in 4L, the point is will it hurt if I did. I have been in places where I went over an obstacle and had a long way to go to the next one so I didn't feel like stopping and shifting into 4H and back again. It's just a question.

Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

Check out my Gallery for a look-see.


Justin - One Happy FTE Member

 

[updated:LAST EDITED ON 05-Dec-02 AT 10:32 PM (EST)]blown
Possibly one day there will come a time when you have to be in low range to get rolling, but need some speed to get thru an obstacle. Since you won't be able to shift to high range in the middle & make it, you'll have to "wind it up" in low. Of course, if you only use your truck for playing, this is a slim chance. But some of us own full-size 4WD trucks because they WILL do what a Suzuki Samurai WON'T, like pull a loaded 18' trailer up a muddy hill on a job site, where you need the inertia of 25mph to make it, but to get 16,000lb rolling that quickly, you have to be in 4L. Common sense.

...and 4L isn't "made for extreme situations" - it's made for situations that require high torque and maximum traction, like off-pavement WORK.




Here endeth the rant!

 

[updated:LAST EDITED ON 05-Dec-02 AT 11:29 PM (EST)]I'm not going to argue with people that have no idea what they are talking about! Also if your guy's little ricer trucks had some power then maybe you wouldn't need to get any momentum! By the way my truck is built just for off-roading. Sometimes street driving (3000 miles in 5 months).

 

Whatever Blowing bronco.. next time do us all a favor and dont reply
k thx
Posts like your that have no relevance to the orginal topic which was over... are pretty much useless anyway.


Rand