# front axle



## ironman_bmfc (May 29, 2003)

I am new to the 4x4 scene and have a few questions. I have an 87 Chevy Scottsdale and I am trying to find out what kind of front axle is in it. I also have a real bad shake in the front end when I hit 35-40 mph and goes until about 60-65. It almost feels like I have a wheel that loose. I had some one tell me to check my ball joints but when I looked at them they were not bad. When I bought the truck it had a warped rotor that was causing a shake upon braking. I want to dump some money into this truck, how do I know if the truck is worth it? I have worked on cars before and currently have a company that mods PWC. So I know my way around a garage ... just not sure what to make of all the 4x4 componants. If any one could give some advice I would appreciate it. Thanks.


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## ironman_bmfc (May 29, 2003)

*Transmissions*

I have a question about transmissions. I looked to see what kind I have and all it says is hydromatic. I looked at chucks site and didn't see anything there about them. What kind is it and is it garbage?


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## plowking35 (Dec 21, 1999)

Hello and welcome to plowsite.
You didnt mention what series truck you have (10-20-30) If it is a 10 or 20 it will have a GM corporate or factory made axel from American axel corp. If it is a 30 series truck, it will have a dana 60 front axel. Most likely the culprit is a bad steering dampner. It looks like a shock mounted horizontal on the front side of the front axel. One side will be u bolted to the axel and the other side will be through bolted to the cross link tie rod.
Dino


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## Chuck Smith (Dec 30, 1999)

Going on your other post, you have an 87. So your original transmission is either a TH 700 or a TH 400. The TH stands for Turbo Hydramatic. On my site is a diagram of the TH 350, TH 400, and TH 700 transmission pans. The TH 350 was replaced by the TH 700 in 1981.










~Chuck


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## wyldman (Jan 18, 2001)

I don't think the Scottsdale package was available on 1 tons,so it must be a 1/2 or 3/4 ton.It would have a GM 10 bolt axle.

Your vibration could be caused by a number of things,like ball joints,bad tires,bent rim,wheel bearings loose,or even bad leaf spring or shackle bushings.It could also be something loose in the steering linkage,like a drag link or tie rod,or even a bad or loose box.The steering dampner will help smooth out some minor front end shake,and big hits,but it should not vibrate without it,or if it is bad.

Most of our plow trucks have the steering dampners removed,as it makes the steering much quicker,and easier on the driver plowing in it for 2 days straight.They are a little twitchy,but they do not vibrate.

Either check everything out top to bottom yourself (if you can),or take it to a shop,and have them go over it all,so you know what is wrong with it. 

BTW - Welcome to Plowsite :waving:


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## wyldman (Jan 18, 2001)

Chuck's right,it's either a 700R4 or 400.Easiest way to tell is to to look at the shift indicator to see if you have OD.If you have OD,it is a 700R4 automatic overdrive.The 700R4 also has a small square pan.

Both are good trannies.The TH400 is a bulletproof 3 speed,they last forever,with proper care.The TH700R4 4 spd OD is not bad,but had some weak points,which were improved on over the years.They can be easily rebuilt and updated to make a good strong trans which gives you a lower first gear (better for plowing or pulling),and the OD,so you it's easier on the engine and improves fuel economy.


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## wyldman (Jan 18, 2001)

You can also eyeball the hubs,to determine which front axle you have.A 10 bolt will have small hubs,which are 3 inches wide.A Dana 60,has much larger hubs,which are over 4 inches wide.


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## Chuck Smith (Dec 30, 1999)

First of all, these are all questions about the drivetrain of one truck, so I am going to merge this thread with the other one.

You have an 87. You say in your profile that it is a 3/4 ton. You have asked about the front axle, and the transmission. I would assume the next question will be about the transfer case. If it is cast aluminum (which I think it is) then it is a NP 208. The 205 was still used in 87, but only behind manual transmissions and TH 400 transmissions in the K/30 models (1 ton). The 205 was not standard in all 1 tons.

The next question will probably be about the rear axle, since that is all that is left 

You most likely have a 14 bolt GM axle. It is possible that it is a Dana 60 too. The easiest way to tell is to count the bolts on the differential cover. The GM 14 bolt has 14 bolts, and the Dana has 10. If your cover has 14 bolts, then you have one of two 14 bolt axles GM used. One is the 10.5" ring gear 14 bolt full floating axle. The other is a 9.5" ring gear 14 bolt semi-floating axle. The full floater is a stronger axle, but the semi-floater is by no means weak. Not sure if your truck has center caps on the rear wheels or not, but if you look at the rear axle hubs, and there are none (so to speak) then you have the semi-floater. If you see a large hub sticking out of the center of the wheel, then you have the full floater.

~Chuck


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## Chuck Smith (Dec 30, 1999)

Going back to your front end problem.... How did you check the ball joints? Did you jack up the front end and use a pry bar to move the tire / wheel assembly while someone else looked, or had someone else move it while you looked? This is the best way to find problems with the front end. It is not like a car where you can grab the tire at 12 and 6 o'clock and wiggle it, then at 3 and 9 o'clock and wiggle it. A pry bar makes a difference.

Check the drag link, as it is the most common part on the front end to wear. You can check that by having someone rock your steering wheel while you look for play in it. Use a flashlight. Check your front axle U joints too. A bad U joint and a faulty automatic locking hub can make weird things happen. Does your truck have manual locking hubs, or the factory auto locking ones?

~Chuck


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## wyldman (Jan 18, 2001)

Chuck - when did they use the Dana 60 in the rear of a pickup ? I have never seen one,and wasn't aware that they ever used them on the mid-eighties trucks.

Excellent info on the rest of the stuff.I never thought to check his profile to see if it was a 3/4 ton or not.That would definitely make it a GM 10 bolt front axle,NP208 case,and a 14 bolt rear.


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## Chuck Smith (Dec 30, 1999)

Chris, I added the "Vehicles / Equipment" field to Member profiles about a month ago. I figured it would eventually cut down some on confusion.

As far as the Dana 60, I myself have never seen one, or spoken to anyone personally that had one. Dino quoted an article in another thread here a while back, and apparently the Dana was used in some trucks. I guess I should have double checked his post, because I don't recall what years it appear. I believe it had something to do with a shortage of 14 bolts at times.

I will do a search and find the post.

(EDIT: http://www.plowsite.com/showthread.php?s=&threadid=9693&highlight=dana )

Ironman, one more thing that you might not know is that your 87 is the only year from 1973 - 1987 (rounded line models) that has an on board computer.

~Chuck


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## Chuck Smith (Dec 30, 1999)

Just wanted to add a few more tid bits. The on board computer only controls the ignition system.

From 1973 - 1986 GM made C and K models.

C = 2wd
K = 4wd

For some dumb reason, in 1987, they changed to this:

R = 2wd
V = 4wd

You may need this info when looking for parts. Many, MANY, parts interchange with 1973 - 1986 models. That is good news for you, and keeps parts cheap. The only parts that don't interchange between all years, is the cab sheet metal. Doors, hoods, fenders, radiator supports, etc. The big change for them came in 1981. They stayed the same until 1987.

You can read a run down of model year differences here:

http://www.chuckschevytruckpages.com/bodynchassis.html

IF you want to know even more about what you have, and if the Options decal is still in your glove box, you can look up all your RPO's (Regular Production Option) on my web site too.

~Chuck


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## wyldman (Jan 18, 2001)

His truck should be computer controlled TBI,which came out in 87,and carries onward until they went with the Vortec motors.The computer controls control the entire fuel and ignition systems.

Some late 85's and 86 motors had computer controlled ignition only using a four wire HEI type distributor and an EST module,which controls dwell and advance curves.No centrifical or vacuum advance was used.In 87,the distributor changed completly with a new ignition module,which also had an external EST module for dwell and advance,that used signals from the ECM to adjust timing.


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## ironman_bmfc (May 29, 2003)

Hey guys thanks for the info. 
I looked at the rear and it apears to be the full floater. I also checked Chucks site with the the tranny pan pictures. It looks similar to the pic of the TH400 but it has angles on the left and right side. Is it still a Th400? It is a 3 speed. So how is the transfer case? Is the NP208 good? Also is this a truck worth dumping some money in? I work for the county sherrifs search and rescue and need a good strong 4x4. I am planning on puting a 6" lift, some 37" tires, and building a 383 for it (forged 3.75 crank, stage 2 rods, keith black pistons, melling oil pump, comp extreme cam, crane valvetrane,march under drive pulleys, weiand x-cellerator intake, holly truck avenger 670 carb, msd 6al ignition, msd blaster ss coil, msd extreme duty distributer and some summit headers with straight pipes). It needs a few things interior wise (new power windows, new weather stripping, etc.) but the body is solid as can be. It has the long bed which I love. I have freinds tell me to just buy a new truck, but i love the look and feel of the older ones. What should I do?


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## ironman_bmfc (May 29, 2003)

As far as the ball joints go .. I did a visual inspection and tried to wiggle them around (I am used to working on 4 wheelers and such). I was reading a post from someone else and they seemed to have the same prob and the wheel bearing was the culprit How hard and how expensive is it to replace the componants int eh front end. Also as far as the gm front 10 bolt ... is it any good or I should I look for a new axle if I keep it? By the way , you have alot of great info on your site chuck, keep it up!


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## wyldman (Jan 18, 2001)

I'd stick with the older truck.The GM 10 bolt is pretty tough,and should hold up OK under normal 4 wheeling.If your going extreme off-road,then look into a D60.

The front end stuff can be a little pricey,but not to bad.Wheel bearings aren't that hard,but you will have to remove the inner and outer hub,and you will need a special wheel bearing nut socket.I would have everything double checked first,to make sure the whell bearing is actually your problem.

If your tranny is a 3 speed,it has to be a TH 400,unless someone swapped in something else.The NP208 will hold up fine under normal use,and it's cheap and easy to work on.If your going extreme wheeling,then a heavier case will be neccesary.

Is your engine fuel injected ? IF it is,then keep it fuel injected.There are lots of good hop up parts available to make more power,and you can't beat the reliabilty,drivability,and fuel economy of the TBI.You can still build the motor the way you like.Just don't go to radical with the cam,or it won't run well.


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## Chuck Smith (Dec 30, 1999)

> _Originally posted by ironman_bmfc _
> * I work for the county sherrifs search and rescue and need a good strong 4x4. I am planning on puting a 6" lift, some 37" tires, and building a 383 for it (forged 3.75 crank, stage 2 rods, keith black pistons, melling oil pump, comp extreme cam, crane valvetrane,march under drive pulleys, weiand x-cellerator intake, holly truck avenger 670 carb, msd 6al ignition, msd blaster ss coil, msd extreme duty distributer and some summit headers with straight pipes). *


A few things I see here.... Is the Wieand intake a dual plane manifold? You definitely want to stick with a dual plane manifold, whatever brand you choose. A single plane is for top end power, and you want low end power and torque.

Not sure if you are aware, but the MSD coil eats up spark plugs pretty fast. Don't get me wrong, it is a great coil, but your motor will eat plugs. Platnum plugs seem to last longer, but they are more expensive to replace.

I don't see any reason to use underdrive pulleys on that motor. You are not going to be running at the track, and it will have plenty of power. You won't notice any real increase with the added cost of underdrive pulleys.

Chris is right, I would stick with the TBI, it is very reliable. It will handle altitude changes and off camber terrain better than a carb. As far as the lift kit, I would go with a kit that comes with 4 new springs unless you plan on loading the bed a lot. the 'softride' type kits really do ride much better than a HD lift kit. The truck will ride like a tank. With 37" tires you will want a dual steering stabilizer. Get the dropped steering arm for the lift kit, because it is easier to install than a dropped pitman arm. If it was me I would go with a 4" suspension lift, and a 3" body lift. Fitting the 37" tires will be close with a 6" lift, and either way you will be trimming a little off the bottom of the front fenders.

Since you will be doing search and rescue, you might consider adding a second battery to power additional accessories, and a high output alternator. A winch can suck a lot of juice, and it only seems natural to have one on a search and rescue vehicle. Off road lights also suck a lot of juice. You can get a second battery tray from many aftermarket body suppliers, and it will bolt right in, since dual batteries was an option on that truck.

You'll need drop brackets or spacers for the front axle sway bar with the lift kit. The 208 t case was used in 1 ton models, so it is a fairly strong t case, I believe it is rated at 10,000# GVWR.

~Chuck


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## wyldman (Jan 18, 2001)

Lots of good info here.Chuck is right with the manifold recommendation.Anything other than a dual plane manifold will kill low end power.With big tires,off road,at low speed,you will NEED gobs of low end power.If you do have (and are going to keep the TBI unit) Edelbrock makes a performer TBI manifold which works well.Stay away from any throttle body spacers,as again,you lose bottom end power.

I will disagree on the MSD coil eating spark plugs.The coil will only fire what actual energy (KV) is required by the plugs.This will not increase the plug firing voltage unless the original coil was maxed out to begin with.It's pretty hard to max out a coil nowadays,as most of the newer e-coil type coils provide way more spark than most engines would ever need.If something is eating spark plugs,it's usually something else,like excessive advance,running hot,or deposits.

The MSD 6AL might be a little harder on plugs,as your firing them multiple times per power stroke,but sometimes the increased efficiency will keep the plugs in better condition so they will last longer.The MSD unit would be the FIRST thing I would upgrade on that truck.It's pretty much a straight plug in to the harness,and makes a good increase in low end power,and overall drivability.It shines even more as you start hopping things up more.It's also good for a few miles per gallon in the economy department too.I put one on my 87 R2500,and loved it.I kept the stock coil,and never had a problem.

I would also recommend a good quality cap and rotor,as the extra spark for the MSD will sometimes crossfire in the cap with cheaper or OEM units.Accel or Wells gold are two that work well.

Chuck also made a good point on the lift.Using a smaller suspension lift,and adding a body lift,makes things easier,and keeps your center of gravity lower.I have driven trucks with both,and the trucks with less suspension lift handle way better,both on and off road.The only drawback is slightly less frame to ground clearance.


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## ironman_bmfc (May 29, 2003)

The intake is a dual plane, now if I keep my TBI will that intake still work? Will I need to remap the TBI after the engine swap? 
When installing the second battery would I just hook them up in series or make the second battery dedicated to my accesories?
I know I am asking alot of questions but I am learning alot and I appreciate it.


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## wyldman (Jan 18, 2001)

You will need a TBI intake.I'm sure there are adapters available,but the restriction caused by the adapter would far outweigh the benefits of changing the manifold.The Edelbrock TBI performer is an excellent manifold.I have installed quite a few.

You may need to burn a PROM for the ECM if you go to wild with your engine mods.This can be difficult and expensive sometimes.Build your engine to suit the TBI,and you'll be much better off.You can then get away with probably an off the shelf superchip.Another option is to get a Holley TBI upgrade,which comes with a high flow throttle body,and an adjustable ECM.

I'd use a 350 four bolt main block,newer Vortec heads,mild port and polish with a 3 angle valve job.Edelbrock performer manifold and cam,small primary tube header,with long 3" collectors,a crossover tube,with 2 1/4 inch duals.MSD 6AL,with stock coil,and upgraded secondary ignition components.Will make good strong bottom end power,with a little more top end than stock.IF you want a little more you can add roller rockers with an increased rocker ratio.

Connect your batteries together,and in parallel.In series would give you 24V,and lots of smoke  This greatly simplifies things.If you want to isolate them you can,but you will need an isolator,and they will have to be wired individually.If you going to go and spend all this time and money on this truck,including adding another battery,I'd move both batteries to the rear framerails somewhere in a box,like the bigger trucks.You can then run bigger batteries (or even one big one) which will give you much more reserve capacity.Group 65 or group 31 batteries have the most capacity,in a reasonable sized case,and won't break the bank.You can then use little short cables to connect the batteries together,and one big 0 gauge or better welding cable to run up front to the starter.I would also add a dedicated starter relay in the circuit as well,and bypass the one on the starter.It will start better,and is much safer.Putting the batteries in the back,and down lower to the ground,helps handling,by better distributing the weight,and saves wear and tear on the front end.Two big batteries can weigh nearly 150 lbs.


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