Wondering what you fellas would do?

[taxreliever]

I would venture to say the shaft has its own o-ring in there some where. But any gritty water that gets in the shifter will stay and ware on that o-ring.

Thanks Mark, but than what about the little electric shift motor...there is nothing there either...if this is true, I would imagine it having a similar issue, right?

Mark, I went back and watch him take the motor off the Tcase and if you look, the shaft that's coming out is surrounded by a ridge which I would imagine sits flush with the electric motor and the shifter......but even so, can't imagine it being water proof....did you watch it? What do you think? What happens if the entire Tcase or the truck is completely submerged?

 

[DNFXDLI]

Hi Ken to answer your questions......



2) 50-55 is the maximum safe operation for 4wd in a stock vehicle period! sure some push the issue..however your taking a big costly risk in doing so.

Question for you..where did you get this from? All my life I have driven at highway speeds in 4wd, both new and old, full and partime.
The only reference I've ever seen to speed is the speed at what you shift in and out of 4wd at.
When I was doing the conversion on the 750, that was one of the questions I asked MH as I was only ever familiar with low speed planetaries...their response to me was drive at whatever speed you want.
Oh, and I'm not asking in a dickish way either!

 

[taxreliever]

Question for you..where did you get this from? All my life I have driven at highway speeds in 4wd, both new and old, full and partime.
The only reference I've ever seen to speed is the speed at what you shift in and out of 4wd at.
When I was doing the conversion on the 750, that was one of the questions I asked MH as I was only ever familiar with low speed planetaries...their response to me was drive at whatever speed you want.
Oh, and I'm not asking in a dickish way either!

I've never known you to be a dickish kinda person Duncan, except to GM....but I'd like to know what you're asking also.

I have heard from others that driving on pavement is a no-no in 4HI at freeway speeds and I never quite understood that.....I thought that's what 4H was for, but maybe not for Broncos?

I do know that my newer vehicles, like my wife's suv is ok to run at 70mph in 4H. We do it every winter when we go out of town and the weather is iffy or is snowing.

 

[DNFXDLI]

The issue with driving in 4HI on pavement can be a problem as each wheel can travel at a different speed....cornering for example. Also some axle ratios are not exactly the same...like 4.09 to 4.11, 3.7 to 3.73...this as well as turning can result is driveline bind that will make shifting out of 4wd a bit more awkward.
This is normally fixed by reversing a few feet and taking the bind away
Full time 4 with a differential in the transfer case is a way around that....it acts just like a regular wheel differential in that it will allow for different individual wheel speeds on a hard surface
Either one (full or part-time) will jerk and bind on hard pavement in a hard wheel lock..it's less noticable off road where the ground will yield.
I drive all my present trucks in 4hi on pavement...typically in winter where is is mixed pavement and snow, never had an issue.

 

[taxreliever]

The issue with driving in 4HI on pavement can be a problem as each wheel can travel at a different speed....cornering for example. Also some axle ratios are not exactly the same...like 4.09 to 4.11, 3.7 to 3.73...this as well as turning can result is driveline bind that will make shifting out of 4wd a bit more awkward.
This is normally fixed by reversing a few feet and taking the bind away
Full time 4 with a differential in the transfer case is a way around that....it acts just like a regular wheel differential in that it will allow for different individual wheel speeds on a hard surface
Either one (full or part-time) will jerk and bind on hard pavement in a hard wheel lock..it's less noticable off road where the ground will yield.
I drive all my present trucks in 4hi on pavement...typically in winter where is is mixed pavement and snow, never had an issue.

Great explanation Duncan, thanks....I got about 90% of that and the rest I'll need to think on or read more about .....but now my question is, does the Bronco have the differential in the transfer case or is that just in new vehicles?

 

[m78]

Thanks Mark, but than what about the little electric shift motor...there is nothing there either...if this is true, I would imagine it having a similar issue, right?

Mark, I went back and watch him take the motor off the Tcase and if you look, the shaft that's coming out is surrounded by a ridge which I would imagine sits flush with the electric motor and the shifter......but even so, can't imagine it being water proof....did you watch it? What do you think? What happens if the entire Tcase or the truck is completely submerged?

I watched it again. looks like Ford is relying on the two machined parts being water tight. I suppose I should pull mine to see if its clean inside.

 

[DNFXDLI]

I'm pretty sure it does Ken, I believe most of the newer ones have some kind of differential in them...others might know more.

 

[BuzzGun79]

Duncan I was taught that through service experience in the private sector,from the past.we also experienced many of our customers trucks,not just Ford but other makers as well that parts were wearing at a rapid rate due to excessive highway speed driving in 4hi during non threatning conditions.transfer case/front differential failure along with universals and stripping of lockouts were pretty common in vehicles subjected to those conditions at least in this area.There is no reason to do this,4wd was not intended for that.you yourself even brought up possible reasons for failure.Jeep literature from my former wrangler backs my statement also.And our Grand Cherokee is another story for its so called sealed units that Chrysler claims is "Non serviceable units" BULL i was not born yesterday,C'mon man.after a pretty heated discussion with the service manager,he sold me the dipstick tool they use to service the transmission with for they come caped off from the factory..I know your not a d... Duncan,im just trying to share the experiences that i have gone through over the yrs to prevent others from the same costly results.some will listen others wont,I cannot get through to everyone.

 

[DNFXDLI]

Duncan I was taught that through service experience in the private sector,from the past.we also experienced many of our customers trucks,not just Ford but other makers as well that parts were wearing at a rapid rate due to highway speed driving in 4hi during non threatning conditions.transfer case/front differential failure along with universals and stripping of lockouts were pretty common in vehicles subjected to those conditions at least in this area.There is no reason to do this,4wd was not intended for that.you yourself even brought up possible reasons for failure.Jeep literature from my former wrangler backs my statement also.And our Grand Cherokee is another story for its so called sealed units that Chrysler claims is "Non serviceable units" BULL i was not born yesterday,C'mon man.after a pretty heated discussion with the service manager,he sold me the dipstick tool they use to service the transmission with..I know your not a d... Duncan,im just trying to share the experiences that i have gone through over the yrs to prevent others from the same costly results.some will listen others wont,I cannot get through to everyone.

No sweat Buzz, I was just curious and always like to hear what experiences people have had. I don't advocate at all running on a hard, dry surface in 4hi at all and don't do it..although with a slippery surface I do.

 

[BuzzGun79]

All is good Duncan...but what troubles me at time is ...No i was not trained by Ford or an ASE program...But i am not a complete idiot either,i may not speak in high tech terms for i had to relate with the customer to make them understand what was going on with their vehicles which in most cases the dealerships failed to do.Now i dont mean to step on anyones toes who makes a living in the dealerships..but we highly succeeded where the dealerships failed in short.

 

[DNFXDLI]

Hey, you just get a broader range of experiences that way!

 

[taxreliever]

They sell AWD vehicles though don't they and if so, would they have these issues as well.

Subaru's have been doing it for years and even the Explorers have had AWD applications for years, right?

 

[DNFXDLI]

I think he's just relaying on what he has found himself Ken, I've had the opposite experience, but having said that, I'm an anal SOB with maintenance.
If a u-joint or slip joint is not maintained then it can wear and take out other stuff.
The old style full time 4 kept the knuckle u-joints and driveshaft always turning from the front diff, I recall those u-joints wearing faster than the part time units.

 

[dustybumpers]

Back in the day, we used to convert the full times to part time. You changed some gears, and added a set of locking hubs.

My blazer when it was full time 4x4, used to eat tires, u-joints, and drink gas like it was water. It took it 2 blocks to make a u-turn.

 

[BuzzGun79]

AWD and 4wd there are differences.The vehicles i reffered to are from the big three automakers not the foreign.what im trying to get across Ken,Duncan dont constantly drive on dry pavement in 4hi there is no need to.Duncan i am the same as far with my maintenance as well...I keep them suckers greased probably more than i should..lol and i myself have not experienced much failure other than common universal wear at higher mileage and that electonic motor,vaccum motors on front differentials in late models.Like anything else man you abuse it ..it will wear or break

AWD = Even power distribution to all 4 wheels

4wd= unless you have posi traction or locker type differentials..your only getting power distribution to the drive wheel,per differential,1 wheel in the rear will spin,and 1 in the front.

 

[BuzzGun79]

The guide lines i gave above are what i do to prevent failures on my own vehicles just to clarify.It is your own choice if you wish to follow them.and yes i am anal about preventative maintenance..it will save you a great deal of grief along with some coin as well,should you keep your vehicles long term.

 

[DNFXDLI]

I agree on the dry pavement 100%..interesting about what manufacturers refer to their 4wd systems though.
Marmon-Herrington that did my 750 conversion calls themselves awd and that would be with or without any sort of axle lockers, and it is just a full time transfer case.
In my case I have both front and rear lockers

 

[DNFXDLI]

And....just for the halibut...here are the stickers on my dash:

 

[BuzzGun79]

There ya go Duncan....I rest my case...

 

[greystreak92]

Wish I had followed this thread more closely. Haven't got the time to read the whole thing right now so I won't comment beyond this.

The only "full-time" t-case ever OEM in the Bronco was the NP203 which had an additional differential to allow for discrepancies between front and rear axle RPM's. The potential differences between front and rear axle RPM's is the critical reason for having either a t-case like the NP203 or a viscous coupler in the driveline to prevent damage to the t-case/driveline should one axle lose traction while the other has grip. This is also why it is NOT recommended to engage a "part-time" t-case on dry pavement especially in the late model Bronco's and F-series wherein the front axle ratio was 0.01 taller than the rear axle. Not a lot, but enough to stretch a drive chain if driven that way for extended periods of time.