my junk yard truck

lapeer20m · 12-01-2006, 06:21 AM

I intercepted this truck last spring on it's way to the scrap yard. It's a 90 chevy with a 350 and auto trans 3/4 ton heavy duty 4x4. It runs and drives, but has some extensive front end damage.

she aint much to look at, but it takes the worry out of any trail damage.

I don't drive her on the road, but use it exclusevly for off road mayhem. I had the 38" super swampers laying around, and the arc welder turned up to 250 amps made easy work of enlarging the fenders. My homemade snorkel cost about 8 dollars. A tube of silicone keeps my plugs/wires,and distributor working even under water. In all, i found nearly all the pieces of the puzzle for free. Lately i've been taking her out wheelin' and have been overly impressed with the off-road ability of this vehicle. The Independent front suspension and tall tires equates to huge amounts of ground clearance. With the IFS, this truck can go places solid front axle dana 60 trucks need 44" tires to go. The rear GM 14 bolt? axle had limited slip, but now sports a lincoln locker (welded spider gears).

i did learn that an extra gallon or so of water inside the automatic transmission is less than desirable. Apparently the properties of water and ATF aren't exactly the same as the truck decided to make every position on the gear selector feel like neutral. Had to remove the trasmission pan, the inpection cover for the torque converter, drill a small hole in the converter, drain all of the very pink juice out, weld the hole closed and reassemble. So far she seems to be working ok. I assume the water came in through a vent tube?? Still haven't tracked that one down. I wish i had a manual trans, but for the price of the truck (nearly free) i guess i can't complain.

the_experience03 · 12-01-2006, 02:17 PM

I'm just waiting for one of those tripod joints on the front to snap. I was a believer in IFS right up until I broke mine rather spectacularly. Now I wouldn't trade my solid axle for anything.

Which 14 bolt rear do you have? There exists a 9.5, 10.5, and 11.5. Now I'm reasonably certain it's not the 11.5 since that wasn't an option until the last generation trucks, but it could be either of the other 14 bolts. the 9.5 or "metric" is a semifloat rear end whereas the 10.5 is a full float rear end so a quick look at the hubs in the back should be all it takes to identify it. I just couldn't tell from the pictures.

What the HECK are you doing with all that frame in the back? Do yourself a favor and torch it off behind the leafspring mounts. I would on mine, but the front of my frame IS the front spring mount and the rear IS the rear shackle mount.

As for the vent on the transmission....I'm not sure what trans you have. It might be a 700R4, it might be a 4L60E, it might be a 4L80E.....it's pretty tough to tell from the pictures. On the plus side, the solution to keeping the water out of them is all the same. Slow down when you're in the water and make sure it's not as deep as the tranny

In all honesty, I will try and find out for you where the vents are. You might want to check the ATF in the t-case and the gear lube in the axles next time you're under that thing. Water in your wheel bearings or differential bearings will REALLY wreck your day.

You might have wished you had gotten a manual tranny, but very few Chevy trucks got the NV4500. You probably would have ended up with a rather worthles Getrag tranny. Manuals aren't necessarily more resistant to water either....the water maybe have left you stranded but was an easy fix.....water and dirt between your clutch discs will leave you stranded and turn mighty expensive mighty fast.

Just to prove that solid axles do have some superior travel, check out the droop travel I have in these pictures of my truck on the lift. The rear is drooped about 12 inches while the front is at about 10 inches of droop. Both ends have about the same amount of uptravel.

Rear

Front

lapeer20m · 01-04-2007, 01:47 PM

well, i should be working on the bus, or perhaps hanging out with my hottie of a girlfriend, but instead I decided to start a new project. Well, to improve upon the current truck project.

I decided I like the IFS when it comes to ground clearance, and the 2500 hd chevy front end pieces are quite heavy duty. If having independant suspension on part of the truck is good, having IS on all wheels is better.....isn't it?

Four wheel drive, four wheel independant suspension, and four wheel steering. Those are the objectives. Taking the front ifs from another chevy and welding it onto the rear of the current project....

here's what we ended up with after 1 day of hard labor. The new front (rear?) end parts cost me $150 plus my totalled VW jetta

more to come.....

Before:

During:

Decided to shorten her a bit

The "new" rear end

After:

We started in the morning, and worked until well after dark. We still have a ways to go, but it should be a lot of fun to play with when it's operational. The significantly shortened wheelbase and four wheel steering should make for a crazy turning radius.

Steve · 01-04-2007, 01:58 PM

Are you using the diff from the front of the other truck in the rear of this one now? Propelling your whole truck on just the two little diffs might cause a lot of wear and tear on them.

lapeer20m · 01-04-2007, 02:04 PM

Quote:

Originally Posted by Steve

Are you using the diff from the front of the other truck in the rear of this one now? Propelling your whole truck on just the two little diffs might cause a lot of wear and tear on them.

It'll be curious to see how many trail miles i get out of the setup before meltdown occurrs. It's kind of a junk yard project, so i won't be out much money if it doesn't work out.

Compared to 1/2 ton IFS parts, these 3/4 ton heavy duty 8 lug pieces are much much larger, and the truck is now much lighter. .

the rear will have hydraulic steering that can be controlled by either the passenger or the driver. Should make for an interactive driving experience.

the_experience03 · 01-04-2007, 02:50 PM

This looks to be an interesting project to say the least.

What do you plan to use the truck for? IFS has it's advantages and it's disadvantages. Walker Evans tried using an interesting IFS on hjis professional rock buggy a couple years ago, actually. From what I've read, the system did work on some counts. Of course there were a whole lot of bugs to work out and they couldn't afford the points so out came the torch and in came the Prorock 60's.

How are you going to connect a hydraulic ram to that stock steering? I think the combination of hydraulic force and those big tires on the centerlink is going to pretzels things in a big fat hurry. You could probably replace the centerlink with a doubled ended ram, but the chances of finding one that is the same length as the current centerlink are....well...not good.

How about the rear driveshaft? What's your plan there? The new driveshaft is going to be offset to one side (passenger). The rear output on the transfercase is not going to allow for the use of a front shaft (and its CV-joint) but you sure are going to want one with that compound angle. Maybe you'll be ok since the driveshaft isn't going to be moving. I'm really not sure, but it's something to look at.

You're going to be giving up a lot of wheel travel and articulation with the new set up, but it might just work. It certainly will be interesting to watch and the fact that it's a junkyard truck makes it that much better. So...what happened to that old 14 bolt rear?

lapeer20m · 01-04-2007, 04:05 PM

I plan to use the truck exclusevily off-road, i think that's obvious. No rock climbing here , mostly mud, sand,snow, and water.

the 14 bolt rear is going off to the scrap yard. It was the limited slip from eaton i believe....now it has a lincoln locker in it.

as for the hydraulic steering....most of the time i don't think there will be any more force applied to the steering components than there would be with a steering wheel. Perhaps i'll keep a spare tie-rod end on hand. Already broke one on the front. I'll add spacers to the cylinder so it cannot travel further than the steering allows. I have a hydraulic assist cylinder off from a big old dump truckIf that doesn't work, i'll go to plan B. .

There is a huge problem that needs to be overcome when putting a front axle on the rear of a truck....if you simply connected up the drive shaft the rear wheels would now turn backwards. On a solid axle you can simply flip the axle right to left to correct the issue....not real easy on an IFS setup.

I decided to mount the axle so the yoke is pointing toward the rear of the truck. I'm going to run a heavy chain and sprocket to a shaft held in place with pillow block bearings connected to the driveshaft.

I know a guy who uses rollerchain and sprockets instead of a transfer case in his mud drag trucks with built big block engines.

The chain and sprocket will also help with another critical problem. The gear ratio on the new and old differentials is not the same. the new one has 4.10:1 and the old is 3.73:1. That's a factor of 1.1. A 22 tooth sprocket on the driveshaft and a 20 tooth sprocket for the differential will be a perfect correction providing a 3.73:1 final drive for both front and rear differentials.

another small issue is the lack of torsion bars. I might correct that with air shocks, or junk yard coil springs, not sure.

phillbus914 · 01-04-2007, 07:17 PM

Hey Jason I got a off road rig now too. My friend gave me his 94 GMC Jimmy. The power steering pump gernaded itself as driving and he didn't want to fix it to so he just gave it to me.

Here's a few shots of it from last summer, we rigged a snorkel up on it and took it up to Silver Lake.

I just got it last week. I spent all last weekend putting the power steering pump on (that was fun) Now I got it at work & I'm getting the front brakes done as they were beyond shot, and trying to rig up some sort of cheap lift to get better ground clearance.

We should get together and go offroading sometime.

Here are some videos of it last summer taking on a few puddles up at Silver Lake. The screeching is from the shop vac hose snorkel.

http://vids.myspace.com/index.cfm?fusea ... =725122361
http://vids.myspace.com/index.cfm?fusea ... =725137055
http://vids.myspace.com/index.cfm?fusea ... =725885439

you may have to have a myspace account to view those... Here's a few that are on youtube.

http://www.youtube.com/watch?v=1nYUUA0FMbA

http://www.youtube.com/watch?v=dqGUT0kcbNE

Elliot Naess · 01-04-2007, 08:03 PM

I do believe you guys are almost ready for Kinetic Sculpture Racing!

the_experience03 · 01-04-2007, 09:18 PM

Hey Phill...when you're ready, the high pinion Dana 30 out of a Jeep YJ is just about the perfect width and has the differential on the correct side for that truck. It even has crossover steering (albeit Jeep's bastardized inverted Y type). Being that a YJ is leaf spring, there won't even be a bunch of brackets to torch off.

lapeer20m · 01-04-2007, 09:23 PM

that 2nd youtube video is excellent!

is silver lake open this time of year? I've never been. I did track down a trailer i can use to move my truck from place to place. We could take the trucks and the buses for a weekend.

phillbus914 · 01-04-2007, 09:50 PM

Quote:

Originally Posted by lapeer20m

is silver lake open this time of year? I've never been. I did track down a trailer i can use to move my truck from place to place. We could take the trucks and the buses for a weekend.

No silver lake is closed for the winter till April 1st.

I'm defiantly down with a bus/offroad beaters trip somewhere soon. I don't have a trailer but I have a tow bar... I need to get a hitch on the bus.

lapeer20m · 01-06-2007, 12:01 PM

We had a couple of HUGE problems to address on day number 2.

First of all, the "new" axle components from the scrap yard were missing the spindle/hub assembly. This is the part that has lug bolts sticking out and allows you to attach the tire/rim. The problem was finding a junk yard hub/spindle for a 1998 3/4ton 8 lug 4x4. The book says only the 96-99 spindles will fit. I called dozens of junk yards and nobody had a spindle assembly....GRRR. Long story short....the hub from a 90 fits just fine. I found one of those for $35.00

problem 2:
The original method we used to attach the 2 frames did not provide adequate support. The 98 frame we're trying to marry to truck is significantly narrower. (really just because the front end of the GM truck frame is not as wide as the rear frame....necessary to allow the tires to steer)

We separated the frame again, and utilized a piece of 8" square tubing to marry the 2 frames together.....

Here is the excess frame we removed from the truck....I should measure and see how long it is...gotta be 10 or 12 feet.

Steve · 01-06-2007, 01:57 PM

Looks like it is really nice for January in Michigan!

the_experience03 · 01-06-2007, 02:21 PM

Ewww....9.5 inch semi float 14 bolt. Good riddance! It's beginning to look like that whole thing just might work. How are you attaching the sprocket to the pinion yoke on the differential? Also...how are you attaching the pillow blocks? Welding to that cast iron diff housing could be....interesting. I guess I'm just assuming it's cast iron. It could just as easily be cast aluminum in a front application, an equally interesting scenario. Atleast it will take care of what would otherwise be a pretty horrific angle on the driveshaft. It's a good thing yoiu can turn sharp. I can't imagine losing all that wheel travel and articulation, especially with those steel "springs" you have shoved into the shock tower right now.

lapeer20m · 01-06-2007, 02:33 PM

the weather has been spectactular! It's been in the 40's lately. We didn't even have snow for Christmas. During a normal january it's far too cold to be working on a project such as this. I wouldn't be suprised if we get subzero temperatures and record amounts of snow in march and april!

Average high for jan in this part of michigan is 28 degrees and the low is 13

lapeer20m · 01-06-2007, 03:57 PM

Quote:

Originally Posted by the_experience03

It's beginning to look like that whole thing just might work. How are you attaching the sprocket to the pinion yoke on the differential? Also...how are you attaching the pillow blocks? Welding to that cast iron diff housing could be....interesting. I guess I'm just assuming it's cast iron. It could just as easily be cast aluminum in a front application, an equally interesting scenario. Atleast it will take care of what would otherwise be a pretty horrific angle on the driveshaft. It's a good thing yoiu can turn sharp. I can't imagine losing all that wheel travel and articulation, especially with those steel "springs" you have shoved into the shock tower right now.

as far as my steel "springs" i put in place of the shocks for now, i am quite certian i'm going to change those over to air shocks. But for now i needed to keep suspension at max height so we could get the front and rear frames welded together.

Pillow blocks will be attached to steel 3" C-channell cross-members attached to the frame. They bolt on, so that'll be no problem....assuming i can get everything lined up properly.

The diff housing is aluminum, but the yoke is steel.....isn't it? I have a great idea on how to get the sprocket and hub perfectly aligned on the yoke (where a driveshaft should attach) and weld her in place. Since the differential doesn't move with the suspension, the pillow blocks and bearings can be connected to the frame of hte truck, not the diff itself.

If only i had air lockers!!! but @ about $1,000 each i don't see that happening anytime soon. Can't do lincoln lockers either...steering is very undesirable with lockers in a steer axle.

it won't be the perfect 4x4, but it's cheap, and highly unique. I'm sure she'll be a decent trail rig, as long the setup is reliable.

the_experience03 · 01-06-2007, 05:04 PM

I don;t think there is an Aussie Locker option for you, but I'm sure you can get a Detroit EZ Locker. They're weaker, but they're cheap and with your weight and power levels, I think the CV axles would still be the weak point. They aren't selectable, but would work just fine.

Here's my other idea...Chevy IFS units pull the long side axle out of engagement with the side gear to allow the front end to "freewheel" or sorts in 2wd. What you could do is weld those spider gears together and then put a vacuum line off the manifold to a valve and then to the actuator. You're going to have to put something in there to engage the new front...er...rear end anyway. I've heard of people shimming the shift forks in actuator, but I can't attest to that fact. There is also always the posi-lok cable actuator option at about $100 per end.

lapeer20m · 01-06-2007, 09:03 PM

Quote:

Originally Posted by the_experience03

There is also always the posi-lok cable actuator option at about $100 per end.

that sounds very interesting! Have to see if i can find info on that....

I had to work until after dark at my real job today, so i just did some mock up to get a better understanding of the fabrication involved in driving the rear axle.

Below is what the basic layout will look like when completed...it's obviously missing the bearings to hold the shafts in place, and still needs a sprocket off of the driveshaft....My gut tells me to use #60 rollerchain instead of the #40 which i just happen to have laying around. The plan is to use #40 in a double configuration.

Max working load for double #40 is 1,620 pounds
Min Tensile (breaking) strength = 6,250 pounds
It seems unlikely to me that i will exceed these working limits

Max working laod for #60 single = 1,980
tensile strenght = 7,030

To attach the sprocket to the yoke and ensure it's square (or whatever the proper term is)

I'm first screwing a nut part way onto the bolt attached to the yoke

That allows another bolt to screw onto the nut keeping everything perfectly square

The sprocket should look something like this when assembled (if you look close enough you'll see that the hub for the sprocket in this photo is actually bigger than the bolt...i'll buy the correct sprocket hub tomorrow) Once everything is in it's proper place, i'll weld the sprocket to the yoke. I'm actually going to use 2 sprockets for a double chain design.

The end result:

I still need to cut off the excess drive shaft pointing towards the rear of the truck. It would be extremely simple to install a PTO shaft off the end of the driveshaft, but i can't think of any sort of power equipment i can connect it too....other than a winch...... hmmmmm.....Since it is a front axle, it comes with an electric actuator to lock/unlock the "hubs". If i unlock the axle with the flip of a switch, i can spin the driveshaft without moving the truck making the pto winch a viable option... This also gives me the option (don't know why you'd want to) of driving with only front or only rear wheels. Even with only the front wheels spinning, i think this truck would go lots of places most 4x4's cannot.

I have to work 24 hours on sunday, I'll get back to the truck on Monday.

GoneCamping · 01-06-2007, 09:25 PM

Not to be the fly in the ointment or anything, but when I look at those pictures I gotta wonder about something. The drive shaft is nothing but very thin tube of hollow metal, and since I'm not exactly sure what you're actually trying to run off of that, I somehow picture that drive shaft shredding itself to pieces very quickly. I work in a heavy truck shop, and have been in the automotive field for 15 years, and I've taken an awful lot of drive shafts to the drive train shop for repairs or rebuilds so I've seen just how frail they are!

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