What's a FJ80/FZJ80 like in RWD?

[ozarkmud]

Curious for those who have done the part-time mod, one way or another, how these handle in RWD. Most seem to like it, but some say they don't like it.

Not sure if there's something about the dynamics of the chassis that isn't meant for RWD, or if there's no such thing.

 

[voodu3]

It’s like a 4Runner with a solid axle swap. If you want to test it out lock your center diff and take the front drive shaft off. The only difference I’ve noticed is on really wet roads it’s not as stable. Just like any rear wheel drive truck.

 

[SpenserAK]

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[CrabCake]

So far I've been happy enough with my PT conversion. That said, I don't drive it in the rain or snow unless I'm on a wheeling trip and get caught in it. From what i've read/heard, the original setup is far superior in these conditions.

I was already doing the under drive gear in my T-case, so it was easy enough to do...that said, I did have to wait for the proper shims for the spool which were not super easy to find in various thicknesses. Honestly, the TG instructions are pretty lame on the need to check your shims when putting the PT spool in (non existent), but thanks to some very helpful vids posted by forum members here, I knew better to keep an eye out on the tolerances, and I'm glad that I did as it was pretty far off.

I had my reasons for giving this a go, but I did save all of the parts including the VC if I ever want to convert back. I don't track mileage as I really don't want to know (it's a toy for me and I have the LRA tank for plenty of on-board fuel), so I cannot comment that..

 

[Gerry McGerry]

but some say they don't like it.

The only difference I’ve noticed is on really wet roads it’s not as stable. Just like any rear wheel drive truck.

Rear end is happy to kick out in the rain on mud tires. Full time is preferable in a daily driven car, IMO.

My Patrol is part time, after a rain it's impossible to park it in my usual spot, same happened with my part time 80 on MT's. Check the grass.

 

[mudgudgeon]

Curious for those who have done the part-time mod, one way or another, how these handle in RWD. Most seem to like it, but some say they don't like it.

Not sure if there's something about the dynamics of the chassis that isn't meant for RWD, or if there's no such thing.

Depends entirely on your driving habits IMO

If you're a sedate driver, you won't notice much difference. Maybe lighter steering feel in some situations.

If you wanna chuck sick skids in the gravel lot beside Walmart, go rear wheel drive.

If you tend to push a vehicle to is limits on windy roads, all wheel drive feels different, but has advantages. If you accelerate into a bend, the front end helps pull you through a corner, and reduces understeer.
In rear wheel drive, understeer becomes more apparent and is exaggerated by body roll

 

[ajordan1975]

I prefer it.
Drives like any other 4x4 truck i've owned in life.
i never liked how my 80 drove in "awd".

overseas the 80 can come with a PT tcase from the factory. soooo the chassis don't give a F if its RWD or AWD

 

[alia176]

I've been PT for 17+ years and never noticed anything different from the beginning. I did it to not worry about front driveline vibrations, and also slowing down the birfield wear and tear. Consequently, I've only serviced the front axle housing twice in the 20 years of ownership because my front parts don't spin unless I'm wheeling.

Back when I did this, I think there was a talk about the front lifting up when you accelerate in rear wheel drive. Accelerating in an 80 is a myth, we all know that. However, if the front shocks have the appropriate rebound valving the lifting is not noticeable, which is my case. I have a turbo for the last few years, and I still don't feel the front end lifting upon acceleration. Maybe it's happening, but I just don't notice it.

I think another interesting side effect of being PT is that you have the ability to dig the rear wheels down in soft dirt in order to level it for sleeping in the RTT. The first time I did this while my daughter was watching me from the outside. Her eyes got so big that it was quite hilarious.

My 7500 lb gal is top heavy, but with the Whiteline sway bars I drive her like I stole her. Curves and windy roads are not a big deal to me, and being rear wheel drive is a non-issue for me.

 

[mudgudgeon]

Accelerating in an 80 is a myth

I drive her like I stole her

Soooo, which is it?

 

[mudgudgeon]

There was a badly off camber intersection i used to drive through daily with my original 80.
In the time I had that 80, Ihad to navigate this corner with the 80 as full-time, as rear wheel drive only, and as front wheel drive only due to taking my sweet time with various repairs

The way the vehicle handled this corner was dramatically different in each format, in the dry or in the wet.
If it was wet, it was easy to break traction tuning up the steep incline.

In allwheel drive, the car would drift forward a little, then claw itself around the corner front wheels first. In rear wheel drive, the back end would slide down the hill, then drift wide around the corner.
In front wheel drive, the front end would dramatically pull itself around the corner.
This one corner kind of illustrated the differences.

One thing I noticed early with full time 4wd, when cornering, you can change the trajectory dramatically by accelerating or coasting around a corner.
Coast around a corner, the front drifts wide. With no change to steering input, step on the gas a little, the front will steer into the corner more.
This is something you can play with on a good road with big sweeping bends. Hold the steering steady in a bend. Accelerate, back off, accelerate, back off. You can easily see and feel the difference. The path of the vehicle will change each time.
Take the same concept to a windier road, and it can make the difference between drifting into the weeds through understeer, or navigating the corner.

One defensive driving technique that most never learn or practice is to stay in a gear that leaves you some room in the engine's powerband so you have some torque and power in reserve. This means you can acclerate around a bend with a greater degree of control vs just coasting around a 25mph bend in "D".
Easier in a manual, but good practice with an auto too.

It's almost always better to drive around a corner vs coasting. This is true with rear wheel drive too. But he advantages of AWD come into their own with this technique, and are somewhat lost if you coast around a corner.

Adverse road conditions is a whole other topic where AWD adds to safety.
Or, emergency collision avoidance.

 

[thatcabledude]

You can leave black streaks leaving the office

 

[thatcabledude]

Rear end is happy to kick out in the rain on mud tires.

I don’t find that to be the case. Stays incredibly straight IMO (4” lift 37x12.50)

 

[alia176]

Soooo, which is it?

Post turbo, I drive her harder but flog her less

 

[smritte]

Glad I did it.
Steering is lighter. Picked up almost 2mpg highway. No more understeer on the mountain roads but AWD was better for fast dirt (over 30mph). I don't do that with my 80 (much).

I tow a 2000# trailer. Over 65 I felt the front drift a bit before I put my castor back to +3. Now its fine.
Running about 4" lift on 33's.

If I lived in a place with snow or anything like that, it would still be AWD. My 80 is my toy and I tend to drive highway long distance to get there. That's the reason I went part time.

 

[Gerry McGerry]

I don’t find that to be the case. Stays incredibly straight IMO

Well it was a turbo diesel manual pov pack with a stripped interior & no accessories other than lift & tires, she was relatively light. BFG KM2's. Even taking off on an incline towing a trailer in the rain would get them spinning and barely moving forward, hated it.

 

[baldilocks]

Curious for those who have done the part-time mod, one way or another, how these handle in RWD. Most seem to like it, but some say they don't like it.

Not sure if there's something about the dynamics of the chassis that isn't meant for RWD, or if there's no such thing.

I went PT several years ago so I didn’t have to bang my head against the wall figuring out driveline vibes ever again. At 4” plus of lift and castor angle on the heavy side of positive, the way I like it, The stock drive shaft and an expensive DC shaft both fail to run smoothly at higher speed; the pinion position does not allow it. That, plus if I break the front diff or axle shaft all I have to do is unlock the hubs and put her back into 2wd rather than removing drive flanges and front drive shaft so I can keep the center diff locked in order to send full power to the rear. I don’t want be bothered with all that when there is still some miles of trail left to camp.

Are you considering converting to part time? If so, why?

 

[ozarkmud]

Thank you all for your replies!

Are you considering converting to part time? If so, why?

I am. We have two rigs and would most likely want to get down to just one. If we keep the FJ80, it has driveline vibration issues and it'd be nice to sort those.

Either way, it's nice to keep wear off the birfields. I've also found RWD to typically be competent enough in the snow. Nice to have the option to put it in 4WD, but AWD all the time feels a bit overkill.

Just an awful lot of miles with slightly less MPG and more wear to deal with. Ended up with a dry spindle bushing, but probably wouldn't have if I kept regreasing the knuckles (or rebuilt them) or if I had a part time kit. The steering does feel a bit heavy. I could see it being more enjoyable to drive in RWD, not even doing burnouts.

 

[mudgudgeon]

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Just an awful lot of miles with slightly less MPG and more wear to deal with.

If you want to know how it feels, lock the CDL, remove the front drive shaft, and drive it like that for a month.

The MPG saving is a myth.
I've never seen anyone post real numbers recording a saving on fuel by converting to part time.

 

[alia176]

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If you want to know how it feels, lock the CDL, remove the front drive shaft, and drive it like that for a month.

The MPG saving is a myth.
I've never seen anyone post real numbers recording a saving on fuel by converting to part time.

Agreed, mpg savings are conjecture at best.

 

[alia176]

Thank you all for your replies!



I am. We have two rigs and would most likely want to get down to just one. If we keep the FJ80, it has driveline vibration issues and it'd be nice to sort those.

Either way, it's nice to keep wear off the birfields. I've also found RWD to typically be competent enough in the snow. Nice to have the option to put it in 4WD, but AWD all the time feels a bit overkill.

Just an awful lot of miles with slightly less MPG and more wear to deal with. Ended up with a dry spindle bushing, but probably wouldn't have if I kept regreasing the knuckles (or rebuilt them) or if I had a part time kit. The steering does feel a bit heavy. I could see it being more enjoyable to drive in RWD, not even doing burnouts.

Your reasoning is solid, and same as mine. After the lift I didn't even bother with a $$ front DS for vibes, just went straight to PT and never looked back. I do have a Toyota DC grafted into my front DS for running in 4HI on rare occasion and more flex. She drives alright but there's a subtle vibe that I can feel when the hubs are locked. One can chase the front vibes with a ton of $$$ and a boat load of frustration.