Full Time 4WD?

Re: Few Questions

I'm used to the term "full time 4wd" meaning that the hubs are always locked and a shifter for the transfer case. Is there such a thing as a 4wd not having a transfer case shifter? All CJ's that I'm aware of had locking hubs (plus the requisite transfer case shifter).

lj

 

Re: Few Questions

Full-time means that there is a differential between the front and rear axles, allowing 4WD to be engaged all the time. Locking hubs cannot be used with this setup. Full-time is always paired with an automatic transmission AFAIK.

There were no CJ-5s with full-time, since the chassis is not long enough to accomodate the automatic. The CJ-7 from '76-79 was available with the TH400 transmission and BW1339 full-time transfer case ("Quadratrac") but there was no full-time system available in CJs after 1979, again AFAIK.

Regarding shifters, the gear drive part-time transfer cases (Dana 18, 20, 300) have large shifters on the floor since you must move the gears around to shift them. Some chain drive transfer cases, like BW1339 or the later New Process cases, have a cable or vacuum actuator. The chain-drive cases (modern design) can have a much smaller shift handle, only a few inches in length, but it's a shifter nonetheless.

 

Re: Few Questions

In the Jeep world, yes. In the truck world, not necessisarily. I've seen a few Dodges and Chevys with NP435/NP203s or SM465/NP203s, respectively.

 

Yes, locking hubs were a dealer or owner installed accessory before 1974 or 75. You don't really need locking hubs ...

 

Re: Few Questions

The conventional wisdom was that the full-time drive is not strong enough to survive the impact load of a manual transmission. This was the Jeep factory line about the BW1339. The 203 apparently came in both part-time and full-time variants. IIRC the full-time 203 is an open differential too, not a torque-proportioning differential like the BW1339 or NP219/229. I expect this is why the 203 can be used with a manual transmission.

 

I normally run around with the front hubs locked in. With a locker in front it actually handles better that way.

 

No lockers on my flattie or the CJ6, but we keep the hubs locked pretty much all the time anyway. When I want 4WD, I want it NOW. Only exception would be a long road trip, which is reasonable in the Tux Park, but would be ridiculous in my CJ3A. I've heard quite a bit over the years about Quadratrac - none of it good. Give me a good ol' transfer case any time - even the single-speed one I had in my '59 FJ25 Landcruiser!

 

I call 'em QuadraTRASH. I have similar sentiments towards the NP203 as well. IMHO they're all gas-suckin', tire-eatin', POS's that went outta style with Gary Neuman and parachute pants.

 

Interesting... I strongly disagree. At its introduction, the original Quadratrac (BW1339) was a revolutionary development. The Quadratrac is an excellent transfer case that only has problems if the owner neglects it. It requires a special juice and, because the chain runs the front and rear axles all the time, the chain will stretch. The proper fluid must be used, and the chain must be replaced every 50K-100K miles. Otherwise it is strong, very quiet and effective, and has negligible impact on fuel economy. Especially if you are driving in snowy conditions, it is remarkably effective - much better than any part-time case.

Here's some more reading if you're interested: http://frontier.net/~mystkblu/quadratrac/

 

I agree with Tim. I heard it was horrible at first but now I am hearing that it is just one of those parts that has to be taken care of in order to work right.

 

I had a 78 Cherokee for many years that we towed big trailers with. I would have another Quad in a moment. Great reliability and traction.

 

Yeah I gotta go with Tim on this one. True not gear driven but not many are anymore. You gotta change the chain every 60 thousand or so. But I've owned several with the setup and maybe I just didn't know any better but I am still surprised at what I was able to do with them.