4WD quit on me!

[Rusty Plowtruck]

Howdy - First off, let me say I know enough about mechanics to get myself in trouble and fix basic stuff, but don't really know the first thing about transfer cases, transmissions and how they work other than in theory.

I use my 78 Bronco exclusively as a plow truck in my yard. It was rode hard and put away wet when I got it a few years ago and I patch things up as the need arises but this is the first time I have had a trouble with 4x4 not working.

Last night during a blizzard it just stopped about halfway through plowing my driveway and it was all I could do to limp back to the house in 2WD. I was banging on it pretty hard moving a lot of snow, but nothing out of the ordinary occurred, I didn't hit anything, but my front wheels are clearly NOT turning all of a sudden.

I made sure the hubs were locked and hadn't somehow slipped out. The transfer case shift lever appears to work going into neutral, 2WD and 4 HI and Lo, but something is definitely NOT right when its in Hi or LO.

Is there a process to diagnose what might be the problem? Could it be my transfer case? The hub(s)? Some linkage issue? It was 20 degrees, snowing, dark and the wind was blowing the snow sideways last night so I wasn't able to see much and hope to be able to take off the plow and pull it in the garage tonight for a closer inspection, but at this point I don't even know what I should be looking for.

Thanks ahead of time for any helpful suggestions!

 

[miesk5]

yo, Here ya go;

Operational Test; "... (engine off, hubs disengaged), crawl under the truck with the transfer case in 2HI, you should be able to grab the front drive shaft and turn it by hand. Also with the hubs disengaged you should see the front axles turning freely. Now engage the hubs and you should not be able to turn the drive shaft by hand. Jack the front wheels off the ground with the hubs engaged, turn the drive shaft by hand, the wheels should turn. The 4x4 light should not be on in 2HI, when in 4LOW you may have a low range light on, (not all trucks have that light) at least mine doesn't..."

Source: by Seabronc (Rosie, Fred W) at broncozone.com

& by the OEM source;

Operational Test; "...To CHECK FOR PROPER ENGAGEMENT, dial both hubs to LOCK and raise the front left corner of the vehicle off the ground. Spin the lifted tire. The drive line will turn if the Hub is engaging properly. TO CHECK FOR PROPER DISENGAGEMENT, dial the lifted wheel hub into FREE and spin the lifted wheel. If the drive line does not turn AND you hear NO ratcheting sounds, the hub is disengaging properly. Repeat step 5- 6 with the right wheel & hub. NOTE: The hubs are not required to seat against the wheel housing when installed, they may move in and out quite easily. This “float” is normal and will not affect performance..."

Source: by Warn®

Have to fig what NP Xfer Case you have in there; so many have swapped em over the years we have to be sure before ripping into it or wasting your time w/wrong info on a diff case;

NP 203

Type: Chain-driven, cast-iron

Low-range ratio: 2.00:1

Weight (lbs.): 165

Lubricant: 10W-30/10W-40

Length (in.): 21.5

Width (in.): 19.0

Height (in.): 15.0

Used by: Ford, Chevy, and Dodge in all 1971-80 full-size vehicles. Use depended on the year, model, engine, and transmission. It is suitable for V-8 power in trucks with GVWRs of up to 10,000 pounds.

The NP 203 is a "full-time" transfer case; it has a set of differential gears which allow for full-time operation; the differential action can be manually locked out. Kits are available to eliminate the action and convert the 'case to part-time. An NP 203 can be distinguished from a part-time NP 205 by its single-piece rear output housing and shift rail coming out the side of the case.

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NP 205

Type: Gear-driven, cast-iron

Low-range ratio: 1.98:1

Weight (lb.): 138

Lubricant: 80- to 90-weight

Length (in.): 13.0 (GM); 16.0 (IH)

Width (in.): 18.0

Height (in.): 12.0

Used by: 1971-1980 Broncos, Blazers, and Ram Chargers (and corresponding full-size pickups); the NP 205 is still used on heavy Dodges. Some Dodge and IH models were longer, "divorce-mounted'' versions. The NP 205 has left- or right-side front outputs and a center rear output. Caution is advised: there were many varieties in NP 205 shaft splines and so forth. A PTO plate can be found on the left side of the 'case.

In Xfer case, look for bad shifter bushings..linkage issues first.

for now, here is what I have:

NP 203 by External depiction in a 78 by Indybronco



203 Rebuild pics in a 79

Source: by nunrush at http://www.supermotors.net/registry/20682/71335

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205 Info & pics Source: by alaskaoffroad akfabshop.com via web.archive.org The NP-205 is smaller and shorter than the NP-203. It is easy to distinguish by its small round 3 bolt cover over the intermediate shaft (green arrow) I drilled and tapped the freeze plug holes for 1/16 Pipe plugs. If you look close at the first two pictures you can see some serious corrosion damage to the aluminum covers

NP 205 Parts Break-Out Diagram w/parts nomenclatureSource: by offroaders.com

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205 Shifter Bushing Replacement pics in an 83

Source: by lightnin (The Tank, Broncinator, John H) at http://www.supermotors.org/registry/vehicles/detail.php?id=5435&s=20540#content

 

[Rusty Plowtruck]

WOW! Thank you so much for all of that information. When I get home tonight I will run those tests and see what I can see and try to correctly identify what transfer case I have.

Thank you SO much. Hopefully it's not a huge deal.

 

[miesk5]

yo! YW & GL!

Hopefully a hub popped a lock ring retainer or at worse the hub body needed(s) very light greaing

 

[Rusty Plowtruck]

Well, I finally had a chance to get the truck unstuck and hauled back to my garage, get the plow off, get the snow kicked off and brought inside to begin diagnosing the problem. Sorry for the delay. Luckily we haven't had much snow.

I didn't get very far with the list because I think I found the problem! /emoticons/[email protected] 2x" width="20" height="20" />

Here are some photos of the carnage in the front left u-joint... or what's left of it.

By null at 2011-01-05

By null at 2011-01-05

By null at 2011-01-05

I need to find my snap-ring pliers before I can get everything apart for a better look, but I'm 99.99% sure I'm going to need some parts that aren't made anymore. What isn't sheared off is pretty mangled and bent and the U-joint is long gone, probably buried in the snow up the road. Maybe I'll find it in the spring.

Is this something that can be repaired with parts, or would it be in my best interest to find a whole new front axle assembly. Also, do you know how to identify what front axle I have, whether its a Dana 60 or a Dana 44?

Thanks again for your help earlier. I'm kind of glad its not the transfer case... but that's assuming I can find some parts to get the beast back on the road!

 

[Seabronc]

You can get those parts from our sponsor Jeff's Bronco Graveyard http://broncograveyard.com/bronco/c-404-dana-44-chrome-moly-axle-shafts.html

Good luck,

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[Rusty Plowtruck]

Thanks for the tip, Seabronc.

UPDATE: I just ordered the front axle kit for the driver's side. It's a bite out of an already stretched budget, but it's a lot cheaper than paying someone to plow my long-ass driveway for the rest of the winter. (The last quote I got was $150 per STORM!) Needless to say, my old Bronco has paid for himself many times over.

I'm sure I'll have lots of questions about swapping out the parts when they get here, but I wanted to thank you guys again for pointing me in the right direction.

 

[Rusty Plowtruck]

I just got in from fartin' around outside in the garage. I would like to thank you guys again for pointing me to the Bronco Graveyard. The axle arrived today and I was pleasantly surprised to find it already assembled. Their customer service was top notch too. They have themselves a loyal customer from now on. Everything went together like clockwork other than that pesky key on the brake caliper - what's the trick? Anyhow, everything came together and not a moment too soon as we are expected to get a foot or more of snow tomorrow.

The test drive went well and I'm 99% positive I'm back in business. Its hard to tell when there is just frozen dirt and ice and rock to drive around on - I will know for sure tomorrow night when I get home from work and have to push that foot of snow out of the way. Then I will believe it.

Again, thank you guys!

 

[Seabronc]

Thanks for the followup and you are welcome. By the way, for things you can't find at The Bronco Graveyard, try LMC Truck http://www.lmctruck.com

Good luck,

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