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Hello all, this is my first post here!

I'm working on turning my 2003 T&C AWD into an overlander, and I am looking for help with the AWD system. I assume it is regularly FWD and switches to AWD when a wheel is spinning. But does anyone know how to set up a system to engage AWD at the flick of a switch? Or is there any advice for how to go about building a system to do that? I don't intend to do any serious offroading, this is more just for fun and exploring back roads.

I appreciate all of your help.
 

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2013 Dodge Grand Caravan
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It seems you want to turn your AWD into 4WD. I don't think that will be possible in a switched system. If all you want to ever do is be in 4WD you could weld your center differential or find a locker to fit it. Both of those would require transmission disassembly, I'm sure.
 

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Welcome, from an owner of a 2004 T&C AWD Limited! I'm going for the same look for mine, but it is pretty stock right now. I put 15" 1994 Ford Explorer wheels with 235/75R15 tires on it, and will be putting a front suspension lift on at my next opportunity (2004-2008 Chrysler Pacifica struts with 1 1/4" strut spacers). Front tires are hitting the fenders over big bumps right now.

The AWD system is always engaged, but has a viscous coupler inside the rear differential front housing. It also uses overrunning clutches to allow rear wheels to spin when front wheels are locked (heavy braking) and to allow rear wheels to pull in reverse. Nothing electrical or pneumatic. The transfer case (called the PTU on these vans) is directly connected to the front differential carrier via splines, turning a hollow ring and pinion to drive the driveshaft going to the rear. The front right axleshaft goes from the front differential spider gear all the way through the hollow center of the PTU and out the other side, to drive the right front wheel. On snow, if I gun it enough to break a front tire loose the rear wheels will also break loose and I can drift the van around a curve. Fun times!

If there was a way to lock that viscous coupler in the rear end selectively, that would be awesome for off roading. It needs the slippage for turning the van on the street, parking lots, etc. The next limitation is lack of rear end parts for the Getrag rear differental, like a limited slip or E-locker. I read a long time ago a limited slip that would fit the front (transmission) existed, but never actively searched for it. These AWD vans also do not have traction control. Recently I also wasn't able to back up my driveway (hill), as one front wheel fell into a trench and spun, then a rear wheel spun and there I sat. I had to drive forward and get a little run going backwards to get up. That is the weakness of open diffs. Still backs up the driveway a lot better than my fwd 3rd gen van did.
 

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2006 Dodge Caravan C/V
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I put 15" 1994 Ford Explorer wheels with 235/75R15 tires on it, and will be putting a front suspension lift on at my next opportunity (2004-2008 Chrysler Pacifica struts with 1 1/4" strut spacers). Front tires are hitting the fenders over big bumps right now.
Have been super curious about the Pacifica swap. There was a thread about a year ago that touched on it, but a lot of the information was misleading or missing. I had a guy put in 1-1/4" spacers while installing new front end suspension, but the camber was so positive that we backed out of the deal. In fact, camber on new suspension is still positive enough to wear the outer edges of my wheels bald which has been annoying me for some time. Some guy in Russia has done the lift with the same spacer parts, but the mechanic I used was maybe not so great.

Currently running stock suspension with 235/70/16's and the worst I get is some scraping sounds while turning at max wheel lock.
 
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Camber can usually be adjusted using the slots in the bottom strut brackets. If they are just holes (not slots), or you need even more range of adjustment on top of using the slots, there are camber bolts that have an offset center (like a cam) and smaller diameter shaft to gain movement. The bolts can be used in either the top or bottom holes as need be. Using all of this, camber adjustment should not be a problem.

My van seems to have the right front wheel toed out. The front of my van is so low compared to the rear, it looks like a muscle car stance. I wonder if a previous owner used quick struts on the front and it has sagged that much since? I gotta do something about it soon, as today I went over a railroad track with an invisible hard bump and again my front right tire ate the fender and bent the lip out. Left front tire rubbed the fender, but didn't bend it.
 

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i'd imagine the best you can achieve with these vans is locking up the rear differential or transfer case, whatever it uses

you might be able to do the same to the front differential, but it's inside the transmission's casing and is known to be fragile
 

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If you could find a live rear axle with the same gear ratio as the PTU (which is almost impossible) you could adapt it to mount to the leaf springs and fab a driveshaft to connect it to the PTU. You would then need a way to disconnect that driveshaft for on the road street driving. There used to be remote driveshaft disconnect kits for flat towing of vehicles behind RV's, but no longer available. That would have enabled using a lever and cable to disengage a synchronizer assembly on the driveshaft to "disconnect" it for street driving, then re-engage/reconnect it for off-road adventures in slick terrain. The ratio is something uncommon like 2.38:1. Then maybe you could find a limited slip or locker for the rear differential in that live axle.
 
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They have this kit. I plan to use it in my next transmision build. If its all steel? ALL GOOD. Then just a Strong Few Magnets needed to pick up worn metal from the unit.

About the Problem Diff.
There is KIT for that.

This thread talk about that.

If you look at this video, you WANT this part for the DIFF now. Lack of LUBE does this.
This video talks about that.

Click here to go to the EXACT right part o the video that shows this new pin.




That part? Where to get it? Id ask This is your transmision about that.


This MYTH about this transmission being weak is more from Folks cutting corners putting it together. Not using the right parts and so forth.
What I can tell you is that just about EVERY part of A604 has been Hashed out and we have fixes for every weak part. Even a custom Computer TCM mod with MegaSquirt.

In theory, if you got a Van and programed the BCM to turn on the Traction control via the ABS system, you could. But then you would have to add AWD ABS Programming. I'm sure there is one out there. But really? Not worth the effort if you ask me.


The Rear Diff? I have not taken apart yet. But a DIFF is a DIFF.


Use the Custom locker, or in this case? Chances are you can get a FULL locking diff in the rear.


Also, if you look at FILTHY motorsports? Chances are this dude that works there seems to know Differentials like Jeepman knows Jeeps. He might be able to recommend something that works. There are all sorts of people who know these parts so much better than the rest of us.


Since someone mentioned Railroad tracks.. And suspension?

If you ask me? If you want to go offroad? Want to make it easy? Put on TIre Chains, and an air lift kit.

I can't imagine you would need anything more then that. Heck I only put tire chains on the rear of my Van. And it goes great. When it was nothing but ICE out here? I put them on ALL 4 wheels. HAD ZERO PROBLEMS.

The air lift kits and Bags can be had for cheap. But again. Here is MY suggestion as I went over this before.

They make these BIG bump stops that just Bolt in for out vans.


Amazonlink


Put those in the back. Your rear suspension is never going to bottom out.

Now make your Shackles bigger.

Now go to ARP Bolts and get the STRONGEST BOLT YOU CAN FIND FOR YOUR SHOCKS.
I may be the ONLY guy who has broken them. Once Broken? YOU ARE FOOOOOKKKED...
So Get the Titanium Bolts if you can. Once the break? No more rear shocks. And you got to go to a Machine shop type place that is willing to dig out your old bolt, and Re thread etc. Its a BAD DAY.


With the Rear Sorted, and the Rear diff and all the driveline stuff in good order? Now the front.

Adjustable coilovers. And your done. If you are going to do this? Put the shock tower reinforcement caps. And get a Front Shock Tower brace. THIS IS IMPORTANT. We don't really have the BEST shock towers out there.
Before INSTALL? I sure hope you put as MUCH Paint and whatever you need to do to make sure rust is not a problem.

Also, A skid plate. MAKE ONE. And for once? Someone makes one.

They also make Bull bars.

The thing about the SKID plate is that IT REALLY should be the LENGTH of the van. It's not hard to do. Thin Aluminum with some Reinforcements should be just fine. Just counter sink the Bolt holes so nothing hits them when you are crawling around out there.

The Front bumper will be gone if you don't reinforce it or have the Bull bar.

Next would be the Rear Bumper. Same thing. I'm not a fan of the STOCK tow hitch as it takes away ground clearance.
But it sure does work well. You can use the mounts for it to make a great rear Scraper so that you still have a Bumper when you come back from your trip off road. Again. ASK me how I know... :)

Your Exhaust tip is going to be A very sad Panda. Try to find a way to make it come out of the Rear Bumper. That should stop all issues.

I also HIGHLY recommend that you get Sway bar end links with Springs or Shock absorbers on them. THey make them for bikes, and they would work great with some tooling. THey are Adjustable as well.

If you want to run Bigger tires in the back, You can Flare out the rear fenders, and use Plastic lips if you want.
The front? Same thing. Wish they made a MINIVAN wide body kit. THat would be cool.

As long as you have a REAL upgraded transmission cooler? You should be fine. The next best CHEAPEST mod is to put some Server PC fans on the stock tow package cooler. You can mount about 3 of them on there.

I would not suggest the STOCK airbox location. But... If you do use it? They do make these
That would stop water from being sucked up. If it were me? I would put a Small hole to drain water from your stock box if you suck some in. Or just use a Cone filter. Up to you.

THe Prop shaft by now has Worn bearings, so I would get that done as well.

Also watch out for the Breathers on the Diff and so forth. You may need to extend those above where you get water in them.

Well. I think thats about it.
 

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I disagree with some of that. The differential pin problem in these transaxles has been fixed in the 4th gens (the 2000 3rd gen saw the first fix/improvement). That universal LSD looks like it's just a spacer and wouldn't do much, and the description says there may be more parts needed for installation and has no specifics or installation instructions. The LSD I read about was an actual friction disk type of LSD carrier, used in Dodge Intrepids for drag racing. Rear diff - no parts available because it is so rare, a one-off made only for our vans by Getrag. Something would have to be custom machined/made for that.

Harder shock bolts aren't the best thing, because harder = more brittle and easy to snap instead of bend. Air bags, while an easy bolt-on solution, do not last long-term in the rust belt with sand and salt water drying them out and abrading holes in them. Better to make lift blocks and get longer bolts/studs to install between the body and leaf shackle brackets front and rear. Rear sway bar end links with springs? What would be the point of having sway bars then, because they would no longer work. Just remove them if you need articulation. The rear frame-mounted hitch is great for plugging in a removable electric winch to get out of trouble (or to pull someone else out). Then unplug it and store it inside.

Bigger tires can fit in the rear, but hard to fit in the front. The limitation is the wheel offset and wheel opening length (by rockers, and bumper cover). The bumper cover is easy enough to trim back, but you can't do much with the rockers. You can remove the body plastic splash guards for room, use a heat gun to reshape the inner fender plastic, and use a hammer to flatten a body seam that sticks out in the wheelwell rocker area. After that, you're at the limit, no matter how much you lift the front. That is AFTER using Pacifica struts and strut spacers to gain lift and tire clearance from hub to lower spring perch. If there was a way to move the wheels a little more forward (shifting the front cradle/crossmember introducing caster issues?) then more trimming of the front bumper would yield more room. More negative-offset wheels (like my Explorer wheels) make the tires move farther forward/aft when turning, rubbing on stuff. That is why you want to stick with front wheel drive offset wheels if you can. I like the look of the Explorer wheels (especially my 1998 Limited wheels) so that is why I'm trying to make them work. Tire chains aren't legal in most places (as well as studded snow tires), so probably not an option. I'm eager to try a Ford Ranger plastic fender flare on a van in the junkyard sometime, and if it fits then get a set of those for my van. The upper strut mounts are fine on these vans if not too rusty (the 3rd gens had a big problem, I have one and rebuilt them myself).

Skid plate is a cool idea, but makes it a real pain to change oil. Needs a cutout feature for access to the drainplug, and a remote filter for access. A skidplate for the gas tank isn't a bad idea, either. The 80's and 90's Toyota trucks had a long plate/guard under the tank, that could possibly be adapted to fit. The bull bar isn't going to do much unless it is secured at the frame at several points, not just the bottom like most of the grill guards are. I found an old police push bar at the junkyard, and will have to cut holes in my bumper cover to install it. I want to bolt it to the top of the front steel bumper, and the bottom radiator support. Should make a nice place to mount some extra lights.

The big wheels are going to suck some acceleration, and you can make up for that by regearing your transmission. The transfer gears on the side of the transmission are easy to get to, and swap out once you have the right tools. They won't change the speedometer reading either (but the bigger tires already did). If you want to really be drastic, some Chrysler Pacifica wagons used the same transmission (basically) and they had a lower geared ring and pinion that could be swapped in. They used 17" and 18" wheels and were a heavy vehicle, so that is why they were geared lower.

The ABS system works, but these vans don't have traction control. There is no factory programming to make the brakes lock a spinning wheel (like on AWD LS platform cars Magnum, Charger, 300C) so that idea is still just a concept. With the changes to these vehicles over the early years, it would be hard to make one thing work for all 4 years of 4th gen AWD, electronically. The whole reason I want to swap my van's electronics with 2001 is to get autostick, which isn't available in 2004 because of the new computer system (and nobody has figured out a way to manually select gears in that system). I also like the EVIC readings that offer real-time fuel mileage, instead of just average only.
 

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Camber can usually be adjusted using the slots in the bottom strut brackets. If they are just holes (not slots), or you need even more range of adjustment on top of using the slots, there are camber bolts that have an offset center (like a cam) and smaller diameter shaft to gain movement. The bolts can be used in either the top or bottom holes as need be. Using all of this, camber adjustment should not be a problem.

My van seems to have the right front wheel toed out. The front of my van is so low compared to the rear, it looks like a muscle car stance. I wonder if a previous owner used quick struts on the front and it has sagged that much since? I gotta do something about it soon, as today I went over a railroad track with an invisible hard bump and again my front right tire ate the fender and bent the lip out. Left front tire rubbed the fender, but didn't bend it.
When I replaced the 2006 OEM suspension on the front with Gabriel G56956/7 Readymount strut assemblies the front end went up about 1 or 1-1/2" higher than where it had been sitting. Previously I wasn't able to fit the 235/70/R16 tires without severe rub. They settled maybe 3/8" in the first month and now it has been 9 months / about 20k miles and they are holding solid.

I'll check if I have camber slots or need the camber bolt. Thanks.
 

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I really wish I did not have so much crap on my plate. I would Love to just pick up a welder, some Metal and and Asian Person who is good at math so I can Make some parts out of steel. From what I have seen other people do? And the Jeep guys? Let alone the GM Dudes with their Van Lifts? Or the Ford GUys? It seems rather easy to do.

Not everyone has Bridgeport. Or a Milling machine. Or a Lathe. But these things are no tthat hard to pick up today to make custom parts. or send them out to get CNC'd.

About the Transmission.


This guy must be my dad.. Hes JUST like ME! WOnder if he ever almost lost a wheel?
 
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