Andy's Auto Body 4350 Albany Ave Webster, MN 55088 (952)-652-2600 Phone/Fax Est.1983 The Below is some 4x4 Chevy Truck stuff for the 4x4 enthusiast What kind of axle(s) do I have? Chevrolet used four different model rear ends and three different model front ends on these trucks. For the rear, the easiest way to tell the difference is to count the bolts in the differential cover, there were 10, 12, and two different types of 14 bolt. The 14 bolts came in a full floating and a semi-floating (like the 10 and 12 bolt) model. The large hub sticking out inside the ring of lug nuts can distinguish the full floating models. The front ends can be distinguished by looking at the differential. The corp. 10 bolts had a circular bolt pattern, while the Dana 44's had an oval shaped pattern with a larger gap on the left and right sides where the axle tubes come out. These two models came factory on half and ¾ ton trucks and used ball-joints instead of king pins on the steering knuckles. The Dana 60 came on 1 ton models and can be easily identified by the king pins on the steering knuckles. The Dana 60 has 4 bolts on the steering arm; the corporate 10 bolt and Dana 44 have 3. What kind of gears do I have? There are two ways to tell for sure, if the glove box decal is not accessible or the gears are not factory. You can look on the ring gear itself, which has the number of teeth on the ring gear and pinion stamped on it, then divide the numbers together. Or jack the rear wheels off the ground, mark the drive shaft and the housing in the same place, slowly turn one tire 1 full revolution while counting the number of revolutions the drive shaft makes. If the drive shaft turns: Slightly over 3 revolutions You have 3.08 About 3 and a half revolutions You have 3.42 About 3 and ¾ revolutions You have 3.73 Slightly over 4 revolutions You have 4.11 About 4 and a half revolutions You have 4.56 Can I interchange different axles? Most axles are direct bolt in replacements. 1 ton frames are narrower than half and three-quarter ton models, so the spring pads would need to be moved. In some cases a "Universal fit" U-joint may be required do to different yoke/ drive shaft sizes. Several auto parts stores carry these. MAKE SURE THE FRONT AND REAR GEAR RATIOS ARE THE SAME UNLESS THE 4 WHEEL DRIVE IS ONLY TO BE USED IN SLICK MUD CONDITIONS! What kind of automatic transmission do I have? GM used three different types of automatics in their trucks. The overdrive transmission that was used was the 700R4. The two three speeds were the Th350 and Th400. The pan of the 350 looks like a square with one corner cut off. What Transfer-Case do I have? Depending on year model and weight rating, you will either have an NP-203, NP-205, NP-208, NP-241. The NP-203 and NP-205 will be found in 73-82 model trucks mostly. The 203 was a full time unit which came almost exclusively behind automatics.The NP-208 will be found in 83-87 models mostly. The NP-241 came on most 88 and newer models. A circular tag on the backside of the case can identify each. There are few exceptions. The 208 and 241 case can be shifted on the fly from 2wd to 4 hi, as long as the hubs are in the lock position. What are the differences between the NP-203, NP-205, NP-208, NP-241 t-cases? The NP-203 is a chain-driven full time case. It has a diffferential in the case itself, to keep the driveline from getting in binds, as well as a lock mode for true four-wheel-drive. The NP-205 is a gear driven rock solid case. Some call it the best one ever made. It is a part time case. The NP-208 is a chain driven part time case. This case was made to replace the NP-205, as the 208 is aluminum, and the 205 is cast-iron. Less weight, better mileage, though not as strong. The NP-241 is considered to be a good transfer case and is stronger than the NP-208. It has an aluminum case and chain like the 208. What are the benifits/drawbacks of the NP-203 Full time system? With the NP-203 you have full-time four-wheel-drive. You have better traction, better takeoffs and better steering control under almost ALL driving conditions on and off-road. Problem is, you have severly degraded gas mileage and drivetrain wear. Your t-case chain will get streched and start popping, your front hubs will wear out and eventually shear, and your tires will not last very long. Can I convert my truck from Full-Time to Part-Time Four-Wheel-Drive cheaply? Yes, in most cases the kit is less than $60 dollars and can be installed by most people in their garage. You will now have 4Hi, 2Hi, N, 2Lo, 4Lo. The main mfg. of part time kits is MileMarker. You will also need to install front locking hubs at the same time to acheive any benefit from this kit. Again, most people can do this at home in the garage. Can I swap a 205 t-case in place of the 203 t-case? Yes, it is a realatively easy swap. First locate a 205 that will mate to your tranny. You must get the correct 205 adapter plate, as the 205 was available with three different configurations. Next unbolt the 203 and bolt up the 205. Most of the frames have holes in the proper places, just move the crossmember forward. You will also need to obtain the front and rear driveshafts off the donor vehicle, as the 205 is a shorter case. This means the front driveshaft will need to be shorter. Also, the 205 has the slip yoke on the t-case, on the 203, the slip is in the driveshaft, and the yoke is bolted solidly to the t-case output shaft. What kind of Lube do I use in my transfer case? The Haynes manual recommends: NP203 10w-30 engine oil NP205 80w-90 gear iol NP208 Dexron II or equivalent automatic transmission fluid. Is there a problem with the power stearing gearbox on Chevy/GMC trucks? Yes, the frame has a tendency to break (the box will push thru the frame) and needs to be reinforced. If you do alot of off-roading or have oversized tires this is mandatory. Why pay $400 for a lift kit when I can use blocks on the front? First time you hit a bump or catch any air, those front blocks will pop right out and then you will know why. :) • Engine Related Questions• What was the first year GM used Throttle-Body Fuel Injection? 1987. What size motor do I have? The only difference between the appearance of Chevrolet v-8 is between big blocks and small blocks. There is a casting number on the back of the engine on the driver's side. This number can be hard to view while in the vehicle, but is possible. If there is no number the displacement of the engine will be stamped in the same location. Which carb is best for off-road? The Rochester Quadrajet is known to be good for off-road and steep inclines. Fuel injection is always the best. To get the most power, I was told to run a high lift cam. Is this ok for off-road. No. A radical cam is not recommended for off-road use. You should choose a cam that gives you low-end torque and a good idle. I'm hearing a "knocking" sound when I accelerate. What is this? Your engine is pinging due to one or more reasons: Your timing is not set properly. The grade of gas you are using does not have enough octane. If your vehicle is newer, the sensor or computer could be at fault. Also make sure your engine is getting cool air. When I first start my truck, I see smoke from the tailpipe. After the startup, it's fine. What's the cause of this? Your valve seals should be replaced. • Electrical Related Questions• After I drive for awhile, my truck does not want to start. I have just replaced the starter/solonoid. Now what? If the starter solonoid get's too hot, it will usually fail until it cools off. This happens with headers sometimes because of the heat they produce. This can be fixed with a Ford remote solonoid or some companies like Summit offer a kit for around $25. "Thanks for Visiting my site" I will be adding new pictures soon.