gkrcr882
SyTyless......for now!
So you've just purchased a Syclone, Typhoon or Sonoma GT, congratulations! These trucks are quick, rare, and can be a lot of fun, but to those who aren't sure what they are doing, can be a nightmare.
Upon first getting your truck home (or wherever you plan to keep/work on it), you should do a few basic things.
1. Check all the fluids & change any old or dirty ones. Basic maintenance applies to all vehicles
2. Perform a basic tune-up. Service records help, and the previous owners word may or may not help, but you will know for sure that it has been done this way. Plugs, wires, cap & rotor and fuel filter. These trucks eat secondary ignition parts, its just how they are.
3. Inspect everything. Look at the underhood wiring, vacuum lines, fluid lines, anything that you can see. These trucks are at least 17 years old now, and the original vacuum lines are most likely junk. Even though you can't see cracks or splits, the original rubber has most likely dried out and deteriorated. Low mileage means nothing here. Many driveability and performance problems can be attributed to these. Pay close attention to the starter wiring near the down pipe, be sure the insulation hasn't melted from contact. Check the lines going from the engine block to the oil filter, they can and do leak as well as the gaskets. Check the plastic tube running over the top of the radiator, are there cracks or broken pieces? If so, your turbo is at risk of ingesting these damaging pieces.
4. Make sure everything is as it should be. Wastegate adjustment is very important on stock trucks as is a complete exhaust system. Many uninformed owners will tighten the wastegate up or remove the cat "to make it faster", but this can cause big problems. TV cable adjustment is also important for shift timing, quality, and transmission life.
5. Go slowly when learning about these trucks. It's very exciting to have a fast truck or SUV, however, trying to do too much too fast without learning the ins and outs will cause more downtime and expense than you bargained for.
A few FAQs acquired over the years:
Q: What is my "truck number"?
A: It's generally accepted to be the last 4 digits of the VIN. Typhoons were not built in VIN sequence, however.
Q: Why can't I tow with my Typhoon? I heard it's because of the transmission.
A: That is false. The same transmission is used in all the other S-trucks & SUV's, half-ton pickups and SUVs. The reason for the "no tow" warning is because the intercooler system is designed for a maximum of 15 seconds WOT at full boost pressure. Towing means you'll be in boost more often, overworking and heat-soaking the intercooler system, possibly leading to detonation. Best advice is don't do it. Syclones have a little more leeway with this since they are inherently lighter, however, use caution and good judgment.
Q: My truck won't start when it's hot, what happened?
A: There is a purple wire running to the starter solenoid, and over time heat from the downpipe can increase resistance in the wire, or the wire may contact the downpipe and short out if the insulation melts. Repairs are covered on many pages on this forum.
Q: The back seat in my Typhoon seems loose, is something broken?
A: No, this is "normal", believe it or not. There was a TSB issued by GM for this issue after these trucks came out, however, many people didn't have anything done.
Q: My rear window is squeaking, do I need a new latch?
A: Probably not. Again, another quirk of Typhoon ownership. Many of these trucks will squeak, rattle, and sound like they are falling apart inside. Best advice for the window is to either lubricate the striker or some have wrapped it with electrical tape to tighten the fit.
Q: It sounds like there is a motor or something running under the rear of my Typhoon, what is it?
A: Typhoons were equipped with Electronic Level Control (or ELC), which is a system of a compressor and two air shocks for the rear. The sound is the air compressor running, which is normal
Q: I rotated my tires, now the fronts stick out and the rears are sucked in. What happened?
A: These wheels are different front to rear to accommodate the difference in width between the rear axle and the front axle so they sit slightly in from the cladding and are even with each other when in their proper locations
Q: What kind of oil do these take?
A: Fully synthetic 10w30 is recommended, however others have experimented with other viscosities
Q: My boost gauge doesn't seem to move through its full range, or it seems "off".
A: These gauges are for decoration only, and are known to be wildly inaccurate. Installation of an aftermarket gauge is highly recommended.
Q: What kind of transmission fluid do these take?
A: Any fluid compatible with Dexron II is suitable. Synthetic fluid is not recommended, however.
Q: What kind of fluid does my transfer case take?
A: Any transmission fluid compatible with Dexron II
Q: What kind of oil should I use in my differentials? Do I need a limited-slip additive?
A: Standard 80w-90 GL5 gear oil is specified, synthetic is acceptable. Do not use any kind of additive for the rear differential, the Gov-Loc limited slip does not require it.
Q: What do I fill my intercooler with?
A: A mixture of coolant and water similar to that of the engine cooling system is preferred. Some have added an additive known as "water wetter" to improve heat transfer and reduce foaming.
Q: The cladding on my Syclone appears dull or chalky. What can I do to make it dark again?
A: Many people use a product made by Mothers called "Back to Black". Several applications are needed for an even appearance, and re-application may be needed depending on how frequently the truck is washed.
Q: What is the stock tire size?
A: 245/50R16
Q: My truck vibrates at high speed on the highway, is something bent?
A: Possibly. The other reason could be that these trucks have two-piece wheels from the factory, which are notorious for being difficult to perfectly balance, as well as being highly susceptible to curb and pothole damage.
Durability/longevity upgrades:
Due to the stress the transmission is under during a boost launch and during any hard driving, an auxiliary transmission cooler is highly recommended, along with a transmission temperature gauge. The fluid should be changed on a regular basis, keeping a close eye out for clutch material or any metal
Due to the high torque output of the turbo 4.3, there are documented cases of the front driveshaft (propshaft) failing in a catastrophic way. When the shaft fails, it often strikes the floor, transmission, and anything in its path. For this reason an upgraded unit (many go with a Gilbert) is highly suggested, or at the least a safety loop of some sort should be installed in the event of failure.
Many have found the spark plug of choice is the NGK UR5, although the stock AC Delcos perform well too. DO NOT use any sort of platinum-tipped spark plugs as they will cause a misfire. Iridium plugs haven't been proven to improve performance in any way, however no negative effects have been found.
Ignition cap of choice is a heavy-duty unit with brass terminals and solid construction. All the major ignition component companies (Accel, MSD, Taylor, etc) make them, and even house-brands featured in parts stores have an upgrade option. Don't skimp on this important system
Spark plug wires are just as important as they must endure high heat, especially on the right side of the engine near the turbo. Many people have had success with Taylor wires holding up well, while some have used MSD.
Mixing and matching tire sizes (overall height) is NOT acceptable with these trucks or any 4wd vehicle. Differences in height cause constant slipping of the viscous coupling in the transfer case and will lead to failure. Best to run the same size wheels and tires front and back, however, there are several proven combinations that are within tolerance.
Some owners may want to experiment with driving without a front propshaft. Yes, these trucks do have the power to obliterate the rear tires at will, and can "break em loose" while going down the road at lower speeds. A word of warning though: By running without the front propshaft, 100% of engine power is transmitted to the rear axle instead of the factory intended 65/35 split. By doing so you run the risk of overheating the viscous coupling and locking it up. You won't notice any undue effects until the front driveshaft is reinstalled, then the truck will hop, bang, and be difficult to steer like a conventional 4wd on dry pavement. The driveline will bind due to not having any differential action between axles and a tire must lose traction to release the tension. DYNO TESTING IS ACCEPTABLE. Very few people (if any) have had VC failure as a result of 2wd dynomometer testing.
Be sure to use the "SEARCH" function if you have any questions, as many times the issue has been encountered by other members at some point. Don't hesitate to create a new thread to introduce yourself, show off your truck, or ask a question; we're here to help and love to see other members trucks. Be respectful of the members here and you will be treated the same:tup:
Feel free to add things as needed, every bit of advice will help someone in the future
Upon first getting your truck home (or wherever you plan to keep/work on it), you should do a few basic things.
1. Check all the fluids & change any old or dirty ones. Basic maintenance applies to all vehicles
2. Perform a basic tune-up. Service records help, and the previous owners word may or may not help, but you will know for sure that it has been done this way. Plugs, wires, cap & rotor and fuel filter. These trucks eat secondary ignition parts, its just how they are.
3. Inspect everything. Look at the underhood wiring, vacuum lines, fluid lines, anything that you can see. These trucks are at least 17 years old now, and the original vacuum lines are most likely junk. Even though you can't see cracks or splits, the original rubber has most likely dried out and deteriorated. Low mileage means nothing here. Many driveability and performance problems can be attributed to these. Pay close attention to the starter wiring near the down pipe, be sure the insulation hasn't melted from contact. Check the lines going from the engine block to the oil filter, they can and do leak as well as the gaskets. Check the plastic tube running over the top of the radiator, are there cracks or broken pieces? If so, your turbo is at risk of ingesting these damaging pieces.
4. Make sure everything is as it should be. Wastegate adjustment is very important on stock trucks as is a complete exhaust system. Many uninformed owners will tighten the wastegate up or remove the cat "to make it faster", but this can cause big problems. TV cable adjustment is also important for shift timing, quality, and transmission life.
5. Go slowly when learning about these trucks. It's very exciting to have a fast truck or SUV, however, trying to do too much too fast without learning the ins and outs will cause more downtime and expense than you bargained for.
A few FAQs acquired over the years:
Q: What is my "truck number"?
A: It's generally accepted to be the last 4 digits of the VIN. Typhoons were not built in VIN sequence, however.
Q: Why can't I tow with my Typhoon? I heard it's because of the transmission.
A: That is false. The same transmission is used in all the other S-trucks & SUV's, half-ton pickups and SUVs. The reason for the "no tow" warning is because the intercooler system is designed for a maximum of 15 seconds WOT at full boost pressure. Towing means you'll be in boost more often, overworking and heat-soaking the intercooler system, possibly leading to detonation. Best advice is don't do it. Syclones have a little more leeway with this since they are inherently lighter, however, use caution and good judgment.
Q: My truck won't start when it's hot, what happened?
A: There is a purple wire running to the starter solenoid, and over time heat from the downpipe can increase resistance in the wire, or the wire may contact the downpipe and short out if the insulation melts. Repairs are covered on many pages on this forum.
Q: The back seat in my Typhoon seems loose, is something broken?
A: No, this is "normal", believe it or not. There was a TSB issued by GM for this issue after these trucks came out, however, many people didn't have anything done.
Q: My rear window is squeaking, do I need a new latch?
A: Probably not. Again, another quirk of Typhoon ownership. Many of these trucks will squeak, rattle, and sound like they are falling apart inside. Best advice for the window is to either lubricate the striker or some have wrapped it with electrical tape to tighten the fit.
Q: It sounds like there is a motor or something running under the rear of my Typhoon, what is it?
A: Typhoons were equipped with Electronic Level Control (or ELC), which is a system of a compressor and two air shocks for the rear. The sound is the air compressor running, which is normal
Q: I rotated my tires, now the fronts stick out and the rears are sucked in. What happened?
A: These wheels are different front to rear to accommodate the difference in width between the rear axle and the front axle so they sit slightly in from the cladding and are even with each other when in their proper locations
Q: What kind of oil do these take?
A: Fully synthetic 10w30 is recommended, however others have experimented with other viscosities
Q: My boost gauge doesn't seem to move through its full range, or it seems "off".
A: These gauges are for decoration only, and are known to be wildly inaccurate. Installation of an aftermarket gauge is highly recommended.
Q: What kind of transmission fluid do these take?
A: Any fluid compatible with Dexron II is suitable. Synthetic fluid is not recommended, however.
Q: What kind of fluid does my transfer case take?
A: Any transmission fluid compatible with Dexron II
Q: What kind of oil should I use in my differentials? Do I need a limited-slip additive?
A: Standard 80w-90 GL5 gear oil is specified, synthetic is acceptable. Do not use any kind of additive for the rear differential, the Gov-Loc limited slip does not require it.
Q: What do I fill my intercooler with?
A: A mixture of coolant and water similar to that of the engine cooling system is preferred. Some have added an additive known as "water wetter" to improve heat transfer and reduce foaming.
Q: The cladding on my Syclone appears dull or chalky. What can I do to make it dark again?
A: Many people use a product made by Mothers called "Back to Black". Several applications are needed for an even appearance, and re-application may be needed depending on how frequently the truck is washed.
Q: What is the stock tire size?
A: 245/50R16
Q: My truck vibrates at high speed on the highway, is something bent?
A: Possibly. The other reason could be that these trucks have two-piece wheels from the factory, which are notorious for being difficult to perfectly balance, as well as being highly susceptible to curb and pothole damage.
Durability/longevity upgrades:
Due to the stress the transmission is under during a boost launch and during any hard driving, an auxiliary transmission cooler is highly recommended, along with a transmission temperature gauge. The fluid should be changed on a regular basis, keeping a close eye out for clutch material or any metal
Due to the high torque output of the turbo 4.3, there are documented cases of the front driveshaft (propshaft) failing in a catastrophic way. When the shaft fails, it often strikes the floor, transmission, and anything in its path. For this reason an upgraded unit (many go with a Gilbert) is highly suggested, or at the least a safety loop of some sort should be installed in the event of failure.
Many have found the spark plug of choice is the NGK UR5, although the stock AC Delcos perform well too. DO NOT use any sort of platinum-tipped spark plugs as they will cause a misfire. Iridium plugs haven't been proven to improve performance in any way, however no negative effects have been found.
Ignition cap of choice is a heavy-duty unit with brass terminals and solid construction. All the major ignition component companies (Accel, MSD, Taylor, etc) make them, and even house-brands featured in parts stores have an upgrade option. Don't skimp on this important system
Spark plug wires are just as important as they must endure high heat, especially on the right side of the engine near the turbo. Many people have had success with Taylor wires holding up well, while some have used MSD.
Mixing and matching tire sizes (overall height) is NOT acceptable with these trucks or any 4wd vehicle. Differences in height cause constant slipping of the viscous coupling in the transfer case and will lead to failure. Best to run the same size wheels and tires front and back, however, there are several proven combinations that are within tolerance.
Some owners may want to experiment with driving without a front propshaft. Yes, these trucks do have the power to obliterate the rear tires at will, and can "break em loose" while going down the road at lower speeds. A word of warning though: By running without the front propshaft, 100% of engine power is transmitted to the rear axle instead of the factory intended 65/35 split. By doing so you run the risk of overheating the viscous coupling and locking it up. You won't notice any undue effects until the front driveshaft is reinstalled, then the truck will hop, bang, and be difficult to steer like a conventional 4wd on dry pavement. The driveline will bind due to not having any differential action between axles and a tire must lose traction to release the tension. DYNO TESTING IS ACCEPTABLE. Very few people (if any) have had VC failure as a result of 2wd dynomometer testing.
Be sure to use the "SEARCH" function if you have any questions, as many times the issue has been encountered by other members at some point. Don't hesitate to create a new thread to introduce yourself, show off your truck, or ask a question; we're here to help and love to see other members trucks. Be respectful of the members here and you will be treated the same:tup:
Feel free to add things as needed, every bit of advice will help someone in the future
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