Random Newbie Questions

algeroth79 · Mar 3, 2005

facts 1990 auto XJ NP231
1 At what speed can you engage your 4wheel drive. I have a friend with a newer xj who engages at 60mph as long as there is no throtle. just wondering before something stupid is done?
2 for my truck is there a max speed for the 4wheel drive?
3 How many have tried to upgrade the TB with a newer TB. I looked thru one website but have not seen other. ( Red Rock 4x4)
4 what backspacing do people have with a ford 8.8 in the rear (disk brakes) I was thinking 3.75"

Thanks to all that give me answers to these questions and to those who bust my chops remember you were newbies at one point too.

Muddy_XJ · Mar 3, 2005

Why does he need 4wd at 60MPH?

copperhead · Mar 3, 2005

Welcome,

1. The owners manual for my 87 Laredo Command-Trac states that 4 Hi can be engaged at any legal speed.

2. 4 Hi should be fine. 4 low is listed at 2-3mph to engage. Shift transmission to neutral before shifting into 4 low. From there I believe the RPM's will let you know when to shift and how fast you can go.

Can't answer the other two.

Kejtar · Mar 3, 2005

copperhead said:
Welcome,

1. The owners manual for my 87 Laredo Command-Trac states that 4 Hi can be engaged at any legal speed.

Yeah, but keep in mind that the legal speed then was 55mph

2. 4 Hi should be fine. 4 low is listed at 2-3mph to engage. Shift transmission to neutral before shifting into 4 low. From there I believe the RPM's will let you know when to shift and how fast you can go.

Can't answer the other two.

In both my 98 and 97 there was a notice sticker that said that 4H should only be used at speeds under 55mph. I also would like to know why would he need 4wd at 60mph? From what the manual says (and it kind of makes sense) going to 4H at speed on a bad surface (slippery/wet) might cause loss of traction at the point when the gears engage.

algeroth79 · Mar 3, 2005

he feels he has more control in the rain in 4hi

copperhead · Mar 3, 2005

Yeah, but keep in mind that the legal speed then was 55mph

In the states, but was it the same (55mph) in Canada? I ask because mine is a canadian XJ, and it reads any legal speed. I don't know if AMC would have changed the manual much for Canada, they did make it in English and French though. For fun it also reads:

"Pour l'enclencher, deplacez le levier de la boite de transfert de 2H a 4H pendant que le vehicule se deplace a n'importe quelle vitesse autorisee"

I think this is all academic, as I agree, if you are already traveling at 60mph, I am not sure 4wd will help you much on slick surfaces. As a friend likes to say '4wd gives you the go, it doesn't help with the stop.'

YMMV

rumblebelly · Mar 3, 2005

Personally, I don't like using 4wd drive above 50-55mph with select trac. I figure if I'm going that fast on a surface where I need 4wd, then I'm going too fast. Especially if I need to stop quickly.

I've even felt a knocking sound every few seconds at 40+mpg if the pavement is too dry in spots in 4 hi. Feels like it's binding up a hit and then releasing.

Basically I use my 4hi as sparingly as possible, plus it just reduces wear and helps with gas mileage.

dmillion · Mar 3, 2005

If the conditions are good enough to be driving 60mph then you have no need for 4WD. Other than that, if it is a CommandTrac transfer case (with no full-time 4WD) then you should ONLY engage 4WD when the conditions are slippery enough that tire slip will account for the differentiation needed between the front and rear driveshafts. Ordinary wet roads during rain are NOT slippery enough for part-time 4WD!

Ynglnggod · Mar 3, 2005

I have a 93 XJ Country Edition, the book says full time 4WD can be used year round, which was a shock to me after driving 4WD trucks all my life, but I had to try it, and they were right, on dry roads full time 4WD doesn't drive any different than 2WD, just higher RPM's and more gas. I prefer the part time 4 hi for most things though. Why would you need 4WD at 60mph? Because you can...

regards,
Vince

DDawg16 · Mar 3, 2005

It can be confusing....
Full Time 4WD means that there is limited slip action between the front and rear axles....or what is really being said, you can operate it full time (while in my mind I want to think 'full' 4WD)
Part Time means you can only operate it part time...and on soft roads that give. In this mode, the front and rear are locked together...i.e., no slip...hence, you can get the xfer case into a bind.

What's your budies name? I want to make sure I don't buy his jeep....

Yucca-Man · Mar 3, 2005

Ynglnggod said:
I have a 93 XJ Country Edition, the book says full time 4WD can be used year round, which was a shock to me after driving 4WD trucks all my life, but I had to try it, and they were right, on dry roads full time 4WD doesn't drive any different than 2WD, just higher RPM's and more gas. I prefer the part time 4 hi for most things though. Why would you need 4WD at 60mph? Because you can...

You've got a different t-case than the original poster though.

If you're driving 60mph and need to switch to 4wd, you're driving too fast, regardless of the legal speed limit.

Driving a NP231 in 4wd in the rain doesn't provide enough wheelslip to keep the t-case in good shape. If there's enough rain to allow hydroplaning and wheelslip, then 60mph is far too fast.

cykaaro · Mar 3, 2005

copperhead said:
In the states, but was it the same (55mph) in Canada? I ask because mine is a canadian XJ, and it reads any legal speed. I don't know if AMC would have changed the manual much for Canada, they did make it in English and French though. For fun it also reads:

"Pour l'enclencher, deplacez le levier de la boite de transfert de 2H a 4H pendant que le vehicule se deplace a n'importe quelle vitesse autorisee"

I think this is all academic, as I agree, if you are already traveling at 60mph, I am not sure 4wd will help you much on slick surfaces. As a friend likes to say '4wd gives you the go, it doesn't help with the stop.'

YMMV

Very true!. As I like to say 'It's 4 wheel DRIVE not four wheel STOP!!!'

red91 · Mar 3, 2005

algeroth79 said:
1 I have a friend with a newer xj who engages at 60mph as long as there is no throtle. just wondering before something stupid is done?

stupid has already occured.

algeroth79 said:
2. for my truck is there a max speed for the 4wheel drive?

Refer: OWNERS MANUAL...

algeroth79 said:
Thanks to all that bust my chops.

anytime.

Random Newbie Questions

algeroth79

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Muddy_XJ

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copperhead

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Kejtar

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algeroth79

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copperhead

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rumblebelly

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dmillion

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Ynglnggod

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