Broke down in the middle of the night

[dreaminbohemian]

Driving out of town my truck broke down. It was the middle of the night and I had to get to Houston for a job the next morning. I took some pictures and my friends picked me up, but they aren’t very useful. It looks like my speedometer came unhooked, wrapped around my foward drive shaft, began to whip around and severed my engine loom going down that side of the engine. I can see that it connects to the downstream O2 sensor, but what else?  There is also a thin metal tubing wrapped around the drive shaft with a little bit of hose on it.   Does anyone have a auto salvage recommended location. Truck is left in a parking lot in Huntsville. I am in Houston TX.

 

 1)What the ~1/8” diameter metal tube wrapped around my driveshaft is from. Is an 87 4.0 AW4 a mechanical oil pressure gauge? 

 

2) I am gonna be able to cut a partial wire loom from a junkyard or if I need to pull the whole thing. The ends of the loom  are nowhere to be seen. 
 

3) Input seal from front diff is wrecked from the cable wrapping foward and into the seal. Can I drive home 250 miles in RWD with whatever oil I can keep in it or do I need to pull and replace that seal first if I can get it running? I have one at home that I was going to replace when I did the forward U joints but I can just buy another if I need to. 

[Salvagedcircuit]

1) That could be part of the front CAD axle vacuum tubing (there's a grouping of 3 aluminum 1/8in tubes to the front axle on the US passenger front side) or part of the return brake lines from the rear prop valve. send photos if you have them.

2) From 87-88, the 4.0L engine wiring harness has a connector, "c101" on the US drivers side of the firewall. It may be easier to disconnect that instead of cutting a harness in a junk yard. The other wiring harness also has a connector on the drivers side firewall, further towards the bottom, that's the entire harness from the inside fuse panel.

3) Not sure.

[Drahcir495]

3 hours ago, dreaminbohemian said:

 

3) Input seal from front diff is wrecked from the cable wrapping foward and into the seal. Can I drive home 250 miles in RWD with whatever oil I can keep in it or do I need to pull and replace that seal first if I can get it running? I have one at home that I was going to replace when I did the forward U joints but I can just buy another if I need to. 

How bad is the front differential leaking from the seal? You may be able to check and top it off as you go, but it sounds like it’s in pretty bad shape. Now when you go to replace it you need to make sure the pinion nut is put in the same spot. There is a crush sleeve in between the inner and outer bearings that is set at at certain preload to protect the bearings from failure. We replace these all the time, so you can definitely do this. Here are some tips to make sure you   get it done without any issues. Wow, this could be a little long .

 

I don’t know what tools you will be able use/have on hand, so you maybe have to improvise.
 

Important to make sure you get the nut in the same spot it came off in as stated above. Here is what you need to make sure it goes back to its position on the pinion. We use a dremill to make a mark on the pinion and into the nut. This way you can match it up.m to the right spot reinstalling it. Make sure you count the threads that are showing above the nut. Very important. Obviously you will have to take the nut and yolk off lol.

When that’s done take care not to scratch/gouge the seal surface when you remove the seal. Let the gear oil drain from the front of the diff. Replace seal and use some rtv to the inner diameter if possible. It’s just a bit more insurance. 
 

Reassembly - clean the threads on the pinion and the inside of the yolk with brake clean. Use rtv inside of the yolk - this prevent the gear lube from seeping out. Be Sure to use red locktite inside the nut so it won’t back off. Don’t forget the washer if it had one. Tighten the nut back on to the same exposed thread count and the mark on the nut and pinion match up. Whew - that was a lot to follow along to. Top off with gear oil and you should be good 

[dreaminbohemian]

20 hours ago, Salvagedcircuit said:

1) That could be part of the front CAD axle vacuum tubing (there's a grouping of 3 aluminum 1/8in tubes to the front axle on the US passenger front side) or part of the return brake lines from the rear prop valve. send photos if you have them.

2) From 87-88, the 4.0L engine wiring harness has a connector, "c101" on the US drivers side of the firewall. It may be easier to disconnect that instead of cutting a harness in a junk yard. The other wiring harness also has a connector on the drivers side firewall, further towards the bottom, that's the entire harness from the inside fuse panel.

3) Not sure.

Do you know what is one that loom with the downstream 02 sensor? Made 25 calls so far an no luck on full looms from 86 or 87, now I'm just trying to figure out what looms would also work to splice in

[Salvagedcircuit]

1 hour ago, dreaminbohemian said:

Do you know what is one that loom with the downstream 02 sensor? Made 25 calls so far an no luck on full looms from 86 or 87, now I'm just trying to figure out what looms would also work to splice in

you want to check the 1988 electrical manual which is here.

 

page 89-91 shows the information you want. On page 89 it shows the O2 sensor is on the injector harness that directly connects to the C101 engine control harness. This should not be that hard to find as every cherokee and comanche from 87-88 had this harness. 1986 did not have a 4.0L in either cherokee or comanche.

 

 

page 90: Engine control harness

 

 

page 91: Engine harness

[gogmorgo]

I would guess at the metal lines wrapped up being for the transmission cooler. New lines are available or you can just replace with hose if you can find the right fittings. These likely would be the source of spilled oil as well unless you’re sure the oil leak is gear oil. They puke pretty good when broken. 
If it is the diff leaking, I don’t know how concerned I’d be about running dry. Maybe stop and check ever so often if you’re stopping anyhow. Pretty common for vehicles to puke from the pinion seals without major concerns. 
 

I’m not so familiar with the Renix harness so I don’t have much advice on the harness repair. But I’m more inclined to repair the existing harness with known problems than replace with a used harness with potential unknown problems to diagnose. But it would depend on how far gone it is and how much work you’re willing to put into it. 

 

[dreaminbohemian]

Do I need to worry about the shield on the knock sensor being completely disintegrated?  I know from low voltage installation wiring that shields are only effective if they drain to ground, but since it has the drain wire even pieces of the foil would drain to ground. I could potentially rewrap the exposed section but given how brittle it is in this 16" I imagine it is ribbons in the rest of the loom.

Edit: It’s home now and I had 10 mins to look at it before going out of town again. Speedo cable  chewed up seals on both ends of the front drive shaft. Took a bit to get it untwisted from the little collar on the output of the T-case. It is still connected to the trans and both ends are ripped so it didn't come loose per se; it either broke in the middle or the metal hose started the chaos.  I just assumed speedo because of my needle bounce. 

The metal and rubber hose has a barb fitting on one end so it’s not brakes or trans cooler. Has a crimped on hose clamp at the transition from hose to pipe. PO put in a newer dana 30 because I don't have CAD so it isn't vacuum lines for that. 

  

There is a T fitting above the gas tank with and open stub of hose but it doesn’t look like it would fit the barb on the metal line. 

 

 

Wires are definitely O2, knock, and CTS. Plugs  are gone, knock sensor looks cracked. 

 

It looks like this was mad enough to make dents in the oil pan and the transmission tunnel before I got it pulled over off the highway. 
 

Looks like I’ll be doing a major overhaul a lot sooner than I expected. 

Edited January 19 by dreaminbohemian
adding information

[JeepSchmidt O'Guinness]

That T-fitting above the gas tank is for fuel evap system which should connet to a thin metal line routed along the other fuel lines then goes up the fire wall then connects to vacuum hose over/behind the engine to the charcoal canister. 

Its hard to tell from the shadows in your pic, but that looks about the right length to be said line. 

[Salvagedcircuit]

Ooof. Try and clean everything up with degreaser and an old rag and check for damage again, It may not look as bad as you thought. Definitely check the brake lines and make sure there are no nicks or dents in them.