Transfer Case: 4404 Full time 2WD conversion - welding the viscous coupling?

[DeadAWD]

Hi again,

As I've mentioned my 1996 AWD is now resurrected and I'm happy to have wheels again. I've been driving it for 2 weeks and all has been fine. Today or tomorrow I'm going to flush out the Mercon and put in Mobil 1 synthetic ATF (I've already purchased it). And I'm saving up my money to replace the ATF in the trans with synthetic too.

But my post is about my old TC case. I want to tear into it. I want to weld it up in a way so that the power goes straight to the back wheels and nothing to the front, effectively making the car 2WD (for summer use and especially for towing). Remove the chain in the transfer case and the front drive shaft too.

Based on common sense and knowledge of planetary gears I think I would have to lock up the viscous coupling and weld the planetary gears to the planetary gear cage. Then I could reassemble the TC without the chain. Voila: 2WD at the rear wheels. I think.

Am I right in thinking that I would have to lock up the planetary gears and the viscous coupling? Or is it something else?

Here is what I was thinking would be limitations.
1. Welding hardened metal parts changes the strength properties and weakens them significantly.
2. I might need to add more AFT to the transfer case.

Does anyone have a locked up viscous coupling from a 4404? Not one that is shot and makes the heinous truck-shaking thumping. But one that is locked up and makes the front wheels chirp a little upon turning. That might be the easiest way to lock up the viscous coupling (instead of welding). Then I might only have to weld up one other thing.

Maybe I want a bolt-in 2WD TC case for summer and towing. Then I will reinstall my AWD case for winter (which is great for snow, rain, gravel, etc).

Anyone have any ideas????

Cheers,
Dave

 

[justin146]

Why not install a 4406 part time 4wd TC?

 

[DeadAWD]

There are three reasons why I was thinking that a converted 4404 2WD TC might be a good idea.

1. Cheap.
2. Easy.
3. I like AWD in the winter, especially since I will not be the only person using the vehicle. 2WD in the winter is no where as safe as AWD.

If I had money I might consider, as best I understand it, an electronic TOD 4406, different drive shafts, sport gas tank (with reduced capacity), 4405 V6 GEM and 4406 TOD modules, new dash bezel, tons of wiring, eliminating my stock rear cats and making a new exhaust system, headaches, etc.

I would have already installed a 4406 TOD case if I could have controlled the electronic 4406 manually with a jury-rigged shifter and minimal wiring. One person made a manual shifter for the 4406 electronic and I PMed him but he didn't respond. And since I needed the wheels I had to make some quick decisions. I still want flexibility and am considering a manual 4406 but the manual doesn't have AWD or TOD capabilities (just 4LOW, N, 4HI, and 2WD).

I could have everything I want if I could just solidify up the input-to-rear output inside the shot 4404 transfer case. Hopefully inexpensively. AWD 4404 in the winter and come spring I'd install the 2WD modified 4404. I might have to spend $7 twice a year in gaskets (and if lucky, nothing).

That's what I'm thinking.

-Dave

 

[coonerboy]

Another option would be to get a 2wd tranny extension housing and driveshaft.

 

[gijoecam]

No need to weld the planetaries... Just weld the two halves of the VC together (be careful.... being a sealed unit, I'm not sure what happens if the the pressure builds up inside), drop the chain, and call it good. The planetaries aren't going to move if the two halves of the VC can't move with respect to each other.

But converting back and forth between winter and summer by swapping transfer cases?? That sounds like a LOT more work than it's really worth... And something I'm not understanding: Where's the advantage to having 2wd in the (relatively short) summer? You're not going to save anything significant in terms of mileage as the whole front end is still turning (with the exception of the front driveshaft).... Towing economy will be essentially unchanged... So why swap t-cases twice a year? It would be a LOT less work to buy a second 2wd V-8 Explorer to drive in the summertime...

I'm just sayin'....

 

[DeadAWD]

Well, to answer your question, I was thinking about trying to make a 2WD 4404 conversion (and swapping transfer cases as needed) not because I wanted better gas mileage but more so for piece of mind. In the summer I plan to drive a lot with the rear of the truck full of stuff and towing a trailer, which weighs down the back of the truck. I will need to go across country again.

The rear loading causes more weight on the rear tires and lightens the weight on the fronts, giving the rear tires a smaller effective rolling diameter than the fronts, which stresses the viscous coupling in the 4404 transfer case, which I believe in my case of driving across country, caused it to fail. (I won't delve into the seeming weakness of the engineering design of the viscous coupling AWD design for towing applications).

With a 2WD modified 4404 I wouldn't have to worry about unequal tire patterns, pressures, unequal effective rolling diameters, and would feel much more comfortable driving across country. I wouldn't have to modify anything in the truck (though I would consider installing a TOD4406 if I could manually control it, as I don't prefer to have to find, pay for, and install so many things).

And now that I've learned how to replace the 4404 and have done it once I'm sure I could do a "remove and replace" in an hour and a half. Heck, I sit at this computer at least that much every day, so I'm not worried about spending an hour and a half a few times a year.

But I'm still looking for a way to manually control a TOD 4406. It seems as thought that might be ideal. And I suppose I should ask, is the Torque on Demand function like the AWD? Could I leave the truck in TOD all winter without worry of burning something out?

-Dave

 

[Turdle]

Get a manual 4406 and love the lever.

It is not that obtrusive, believe me.

 

[gijoecam]

OK, I'm not trying to talk you out of it, but let me give you my .02 on each of those concerns... Might just give you some more food for thought.

Well, to answer your question, I was thinking about trying to make a 2WD 4404 conversion (and swapping transfer cases as needed) not because I wanted better gas mileage but more so for piece of mind. In the summer I plan to drive a lot with the rear of the truck full of stuff and towing a trailer, which weighs down the back of the truck. I will need to go across country again.

The rear loading causes more weight on the rear tires and lightens the weight on the fronts, giving the rear tires a smaller effective rolling diameter than the fronts, which stresses the viscous coupling in the 4404 transfer case, which I believe in my case of driving across country, caused it to fail. (I won't delve into the seeming weakness of the engineering design of the viscous coupling AWD design for towing applications).

First, with regards to the tire, the rolling circumference does not change significantly simply because you've loaded one end more than the other. Statically-speaking, on my Sport (which weighs within 200 lbs of your 4-door), the front axle weight is 2250lbs and the rear axle weight is 2050lbs, a difference of roughly 10%, biased to the front end. When I would hook up my boat, with a mere 300 lbs of tongue weight, it would transfer 100lbs of weight off the front end, resulting in axle weights of 2150lbs on the front and 2450lbs on the rear, a difference of 350 lbs biased towards the rear... Closer to 15%.

Now, with the same scenario on a 4-door, I wouldn't expect there to be quite as much weight transfer, and I would anticipate a slightly more rearward weight bias to start, so I suspect the numbers would be similar. What I'm trying to say is that it's likely that you're already experiencing the same sort of desparity in rolling radii you're concerned about avoiding when you tow. Make sense?

The grim reality is that for towing and hauling simultaneously, the rear axle is grossly under-capacity for the application. The rear axle on mine is rated at 2650lbs GAWR. Placing just 300lbs of tongue weight on the hitch transferred an extra 100lbs off the front axle, resulting in an axle that was within 200lbs of the GAWR. A heavy cooler and a couple friends in the back seat would easily have exceeded the GAWR for the truck... Not a good thing. Your numbers may vary slightly from mine, but again, I suspect you'll find that if you actually measured the weight on that axle, your intention is to grossly overload the rear end of that Explorer, which we all know isn't good.

The third point I wanted to make is that to combat the 'squatting' condition you're so concerned about, you can add a weight distributing hitch setup to your rig. That will help distribute the additional axle load over the front and trailer axles as well. Squatting suspension in and of itself isn't necessarily a sign that the tires' circumference is changing significantly. IMHO, if the tires squat so much that they bulge under load, the axle is likely way over its limit to start with.

Now, back to the mechanics...

With a 2WD modified 4404 I wouldn't have to worry about unequal tire patterns, pressures, unequal effective rolling diameters, and would feel much more comfortable driving across country. I wouldn't have to modify anything in the truck (though I would consider installing a TOD4406 if I could manually control it, as I don't prefer to have to find, pay for, and install so many things).

I think you're over-thinking it.... as I mentioned, I don't think the difference in rolling circumference is enough that it'll matter as you probably are already experiencing it. I'd be curious to see the scale numbers empty, and loaded both with and without the trailer. Any CAT scale can give you those numbers for $8.50 for the first pass, then an additional $1 for subsequent passes. It's good info to know instead of guesstimating it.

But I'm still looking for a way to manually control a TOD 4406. It seems as thought that might be ideal. And I suppose I should ask, is the Torque on Demand function like the AWD? Could I leave the truck in TOD all winter without worry of burning something out?

Easy. There are several versions of the 44-06.... The Expeditions used a system that's essentially a super-sized 44-05 like the V-6 Explorers have. The brown wire mod works just as well on them as it does on the Explorer, however, some of the Expeditions also used a system that had 2wd, 4auto, 4high, and 4low. But grafting the controls into an Explorer? There's a wiring nightmare in the making. The manual 44-06 would, by far, be the easiest way to accomplish what you want to do.

And no, the TOD function is nothing like the AWD function. It's essentially rear-wheel-drive-until-they-slip. It's automatic part-time 4 wheel drive, not all wheel drive. No power is put to the front wheels until the computer tells the case to lock. It varies the duty cycle over a range of values, but it doesn't lock in auto mode. 4high locks it in at 100% duty cycle.

Like I said, just some food for thought... Personally, I'd stick with the AWD setup and take precautions to ensure I'm not overloading the Explorer, and not worry about it. People have towed millions of miles over a decade or more with that setup, and I have yet to hear of any cases where doing so has directly caused any issues with the VC.

 

[DeadAWD]

Thanks gijoecam (and others) for your input.

I haven't had internet recently so sorry for the time away.

I've now gone 4 times to the local weigh station but it has been closed each time. It makes me think that maybe they are indefinitely closed.

I've had more time to think about it and I took a look at an Expedition with a switch on the dash: 2WD, A4WD, 4HI, 4LOW. I like it.!!! I like how the TOD functions (rear wheels only until they slip) but it doesn't seem like a viable option for me due to time and mostly money. It would probably be cheaper to buy a used Expedition, which I'm not going to do: too big for me. I like the size of he Explorer.

The AWD drives so well here in the Pacific NorthWET. So for now I'm going to do nothing. Hope that this "rebuilt" AWD transfer case holds up (maybe even buy a spare) and focus on some of the other things I want to do: replace the differential gear lubes with synthetic (already purchased) and put in a new seat belt receptacle (since the spring must have broken inside and it no longer holds the buckle in).

Thanks again everyone,
Dave

 

[410Fortune]

dude you didnt say anything about why you dont consider the bolt in bw 4406 manual t case conversion?

http://www.explorerforum.com/forums/showthread.php?t=166605&page=1&pp=20

no dash switch, no messing with tailhousings or swapping t cases every 6 months...just 2wd with on demand 4hi and 4 low
best mod you can do to a 5.0l explorer imo it went from soccer mom suv to truck in one step
conversion pays for itself in towing and daily driving mpg too......... no full time awd sucking your fuel

 

[DeadAWD]

Hi 410fortune,

I would really like some kind of AWD or TOD functionality. I know the rear end tends to cut lose a lot if in 2WD (rear). I am currently living in a very wet, slippery and steep place. Always uphill or downhill. It rains every *&$%*ing day. Just pulling out of the grocery store you can hear cars spin their tires. My lady doesn't need that. I don't need that. I've grown to like the AWD. The truck drives great. But I'd still like a 2WD option for a summertime cross country trip.

The explorer TOD case that has 2WD, A4WD,4HI, 4LO seems ideal in terms of functionality (even thought I'd have to cut into the original stock exhaust system to eliminate the rear cats, or at least move them, and hammer on the body and gas tank a little) but right now I'm not willing to upgrade all the sensors and gizmos necessary to get the TOD functionality to work (it needs to detects wheel slip, right?).

I don't really like the idea of eliminating the rear cats, and LESS SO cutting into the body for a manual 4406. I'm still considering it thought as I don't want to have to deal with wiring and stuff. And I found a rebuilt, guaranteed manual 4406 for $375 to $400 delivered.

I'm currently driving around happily with the replacement 4404 that I installed after mine went DEAD.

So I'm off to the junk yard tomorrow: seat belt buckle, trailer hitch and I'll look around for transfer cases, just out of curiosity. The guy said that he'd charge $150 for the Explorer cases.

-Dave

 

[410Fortune]

I live in Colorado, my house is at 5200' my work is at 7500' we get all four seasons, including 18" of snow overnight

when its wet or slick out at all I just use 4x4 hi, with an open front diff and a limited slip rear, the 4x4 doesnt bind up even jsut on wet roads ( unless you take a bunch of sharp turns)

Wiring in the awd t case is a PITA, others on this forum have done it, but I just reach down and pull it back from 2wd to 4x4hi antime under 45mph.... works great in all weather conditions... 2wd rules for towing and the 4 low in the 4406 t case is a monster low

just a cheap simple bolt in conversion, but its not for everyone!! I like complicated too!!

 

[Mosin302]

yup, i brought back a thread from the dead ( zombie thread ) but has anyone had experience with a welded VC? Its exactly what im thinking of doing with a bw4404 with a bad VC while i rebuild a different bw4404.

And no bw4406 conversion. Its not needed on this vehicle. 4wd lo is on the straight axle chebby and i love the awd