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Old Jan 29, 2007 | 02:06 PM
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Default Trans oil

Looking to put tran fluit in trans can;t find Dip stik or filler plug. my vette is a 2004 automatic.
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Old Jan 29, 2007 | 02:27 PM
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Transmissions and Rear Axle

The GM Hydra-matic Division's, 4L60-E automatic transmission is base equipment on C5 and comes in a version used only on that platform. Not only is it specific to the rear transmission layout, but it's beefed-up over C4 4L60-Es with a more robust torque converter, a new fluid pan for more consistent fluid pressure during high lateral acceleration and revised calibration. Wide-open-throttle shifts now occur at 6000 rpm. Shifts are quicker and shift timing is tightened up. To improve durability, transmission controls include torque management, which retards timing for a fraction of a second during WOT shifts to reduce shock loads.

One difference between C5 and C1-4 is found when checking the automatic transmission fluid (ATF) level. There is no dipstick. Fluid checks are accomplished while working under the car with the engine running. This may involve hot fluid, powertrain and exhaust parts so we suggest wearing a pair of the Mechanix Brand gloves we talked about in Part One or an equivalent to protect your hands.

Support the car on stands or lift it with a hoist. If you did not read the jacking instructions in Part One of this series; before jacking the car, review them or read the jacking instructions in the Corvette Service Manual. Some jacking points acceptable with other vehicles you may have worked on, if used on a C5, will damage the car.

If you are going to check the trans with the car on stands, make sure it is high enough for you to safely move and work while the exhaust system is at operating temperature. Start the engine and, using the "gauges" button on the driver information center (DIC), put transmission temperature on the IPC display. Run the engine until the trans temp is between 86o and 122oF. Apply the brakes and shift into each gear for a few seconds, then shift back to park.

Set the parking brake, leave the engine running and crawl under the car. Position a drain pan under the fill plug area and remove the plug. If fluid dribbles out or is right at the bottom of the fill hole, your transmission is full. If fluid leaks profusely, it was overfull and you should allow the excess ATF to drain into the pan. If no fluid comes out you will add more in a minute.

Inspect the fluid color. If necessary use a small screw driver or a hex key as a dip stick. Red or red with a light-brownish tinge is the normal color. If the fluid has a medium-to-dark brown color or smells burnt, change the fluid and filter. If the fluid has a cloudy or milky appearance, it's contaminated with coolant. The solution to that is beyond the scope of an article on basic maintenance. See the Service Manual for further information.

If you need more fluid, add enough to bring the level up even with the bottom of the fill plug hole, replace the transmission fluid fill plug and shut off the engine. Your fluid check is complete. If a large addition of fluid was required, there is a leak somewhere that needs to be repaired. If the leak is not obvious, see the Service Manual for information on leak detection. Admittedly, checking the C5 ATF can be an awkward, messy operation. Before you do it, get the car up in the air and visualize the procedure.

General Motors aggressively sells reduced and, even, no maintenance of certain systems on its cars. While conceptually, reduced/no maintenance may appeal to those at Chevrolet responsible for marketing America's Sport Car; we remain unconvinced that some of the advertised maintenance intervals are appropriate when maximum durability of a high-performance car is desired.

Corvette is said to have a 100,000 mile, ATF and filter change interval, however, there is an exception to that, noted in the Service Manual. If your C5 is: regularly operated in heavy traffic when the ambient temperature is above 90oF (temperature near the road surface on just a warm day may reach that), operated in hilly or mountainous areas or operated in a high-performance duty cycle, the fluid/filter change interval drops to 50,000 miles. Seems to us that the "normal" duty cycles of many C5s precludes the 100,000 mile change interval. So much for marketing, eh?

The Technical Staff at Vette fells that 50,000 miles should be the maximum mileage between trans fluid and filter changes for the majority of fifth generation Corvettes. If you run your automatic car hard, such as autocrosses or drag racing in the hot summer, we suggest doing it at 35,000 miles or as soon as possible after a fluid check that shows the ATF turning brown.

Even though we suggest a trans fluid/filter change at half-to-a-third the advertised interval, that is still more than twice what GM recommended for C4s operated under any of the three conditions listed above. How can that be, considering the basic transmission and the fluid are the same? Simple. From a transmission cooling standpoint, C5 is a better car than was C4. The enemy of any automatic trans is high fluid temperatures. If peak fluid temps are reduced, fluid life increases.

Changing ATF in a C5 is no more difficult that it's been in Corvettes of the past. Support the car safely, place a drain pan under the transmission and remove the fill plug. With the engine not running, the trans pump is not circulating fluid so there will be significant drainage out the fill plug hole. Once that stops, support the trans pan and remove its bolts. Carefully remove the pan and drain the remaining ATF. You may need to tap the pan with a soft hammer to break it loose.

Once the pan is off, carefully inspect its bottom. There may be a silver or gray residue there. A tiny bit of residue is normal, however, a significant amount means the transmission has a problem. The definition of a "significant amount" is hard to characterize, but my instructor in an automatic transmission overhaul class I took oh, so long ago, used to say, "If you see more than a dime's worth of metal in the bottom of the pan, overhaul it." Be it a dime's worth or a significant amount, if you see that in the trans pan, put it back on, refill the trans and take the car to a transmission service facility for diagnosis and possible repair.

If there is no residue or a just tiny bit, set the pan aside. Note the position of the filter to aid in installing the new unit. Then, remove it by gripping it firmly and pulling down while twisting a bit. Discard both filter and filter seal. If the seal is stuck up in the valve body, pliers will usually pull it out. Remove all traces of the old gasket from the transmission case and pan. If a significant amount of the gasket is stuck to the pan and you have a quarter-inch-chuck, die grinder, a great way to remove it is with the Gasket Removal Kit from Standard Abrasives Motorsports Division. This kit contains abrasive discs that fit on the die grinder and will quickly remove gaskets but not harm the pan. Because of the threat of gasket and abrasive particles getting into the transmission do not use those discs to remove gasket material from the trans case. That you will have to do with a scraper.

Obtain an ACDelco trans filter kit (p/n TF306). Install its new filter seal in the valve body then push the new filter in place. Clean out the trans pan and look closely at its bolt washers. Their flat sides go towards the pan. If they are reversed, get new bolts. If they are not reversed, reuse the bolts. Apply the new gasket to the pan. Install the pan and torque the bolts to 8 ft/lbs.

Add fluid until it leaks out, then install the fill plug. Perform the fluid check procedure discussed earlier and, if necessary, add more fluid. Since 1994, the factory-fill fluid in Corvette automatics has been an organic-based ATF meeting the Dexron III specification. A suitable performance upgrade would be a switch to or Red Line Oil's D4 Synthetic ATF or Mobil 1 synthetic fluid.
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Old Jan 29, 2007 | 03:35 PM
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Dexron 6 is good too.
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Old Jan 29, 2007 | 07:06 PM
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Originally Posted by dcblackc5
Transmissions and Rear Axle

The GM Hydra-matic Division's, 4L60-E automatic transmission is base equipment on C5 and comes in a version used only on that platform. Not only is it specific to the rear transmission layout, but it's beefed-up over C4 4L60-Es with a more robust torque converter, a new fluid pan for more consistent fluid pressure during high lateral acceleration and revised calibration. Wide-open-throttle shifts now occur at 6000 rpm. Shifts are quicker and shift timing is tightened up. To improve durability, transmission controls include torque management, which retards timing for a fraction of a second during WOT shifts to reduce shock loads.

One difference between C5 and C1-4 is found when checking the automatic transmission fluid (ATF) level. There is no dipstick. Fluid checks are accomplished while working under the car with the engine running. This may involve hot fluid, powertrain and exhaust parts so we suggest wearing a pair of the Mechanix Brand gloves we talked about in Part One or an equivalent to protect your hands.

Support the car on stands or lift it with a hoist. If you did not read the jacking instructions in Part One of this series; before jacking the car, review them or read the jacking instructions in the Corvette Service Manual. Some jacking points acceptable with other vehicles you may have worked on, if used on a C5, will damage the car.

If you are going to check the trans with the car on stands, make sure it is high enough for you to safely move and work while the exhaust system is at operating temperature. Start the engine and, using the "gauges" button on the driver information center (DIC), put transmission temperature on the IPC display. Run the engine until the trans temp is between 86o and 122oF. Apply the brakes and shift into each gear for a few seconds, then shift back to park.

Set the parking brake, leave the engine running and crawl under the car. Position a drain pan under the fill plug area and remove the plug. If fluid dribbles out or is right at the bottom of the fill hole, your transmission is full. If fluid leaks profusely, it was overfull and you should allow the excess ATF to drain into the pan. If no fluid comes out you will add more in a minute.

Inspect the fluid color. If necessary use a small screw driver or a hex key as a dip stick. Red or red with a light-brownish tinge is the normal color. If the fluid has a medium-to-dark brown color or smells burnt, change the fluid and filter. If the fluid has a cloudy or milky appearance, it's contaminated with coolant. The solution to that is beyond the scope of an article on basic maintenance. See the Service Manual for further information.

If you need more fluid, add enough to bring the level up even with the bottom of the fill plug hole, replace the transmission fluid fill plug and shut off the engine. Your fluid check is complete. If a large addition of fluid was required, there is a leak somewhere that needs to be repaired. If the leak is not obvious, see the Service Manual for information on leak detection. Admittedly, checking the C5 ATF can be an awkward, messy operation. Before you do it, get the car up in the air and visualize the procedure.

General Motors aggressively sells reduced and, even, no maintenance of certain systems on its cars. While conceptually, reduced/no maintenance may appeal to those at Chevrolet responsible for marketing America's Sport Car; we remain unconvinced that some of the advertised maintenance intervals are appropriate when maximum durability of a high-performance car is desired.

Corvette is said to have a 100,000 mile, ATF and filter change interval, however, there is an exception to that, noted in the Service Manual. If your C5 is: regularly operated in heavy traffic when the ambient temperature is above 90oF (temperature near the road surface on just a warm day may reach that), operated in hilly or mountainous areas or operated in a high-performance duty cycle, the fluid/filter change interval drops to 50,000 miles. Seems to us that the "normal" duty cycles of many C5s precludes the 100,000 mile change interval. So much for marketing, eh?

The Technical Staff at Vette fells that 50,000 miles should be the maximum mileage between trans fluid and filter changes for the majority of fifth generation Corvettes. If you run your automatic car hard, such as autocrosses or drag racing in the hot summer, we suggest doing it at 35,000 miles or as soon as possible after a fluid check that shows the ATF turning brown.

Even though we suggest a trans fluid/filter change at half-to-a-third the advertised interval, that is still more than twice what GM recommended for C4s operated under any of the three conditions listed above. How can that be, considering the basic transmission and the fluid are the same? Simple. From a transmission cooling standpoint, C5 is a better car than was C4. The enemy of any automatic trans is high fluid temperatures. If peak fluid temps are reduced, fluid life increases.

Changing ATF in a C5 is no more difficult that it's been in Corvettes of the past. Support the car safely, place a drain pan under the transmission and remove the fill plug. With the engine not running, the trans pump is not circulating fluid so there will be significant drainage out the fill plug hole. Once that stops, support the trans pan and remove its bolts. Carefully remove the pan and drain the remaining ATF. You may need to tap the pan with a soft hammer to break it loose.

Once the pan is off, carefully inspect its bottom. There may be a silver or gray residue there. A tiny bit of residue is normal, however, a significant amount means the transmission has a problem. The definition of a "significant amount" is hard to characterize, but my instructor in an automatic transmission overhaul class I took oh, so long ago, used to say, "If you see more than a dime's worth of metal in the bottom of the pan, overhaul it." Be it a dime's worth or a significant amount, if you see that in the trans pan, put it back on, refill the trans and take the car to a transmission service facility for diagnosis and possible repair.

If there is no residue or a just tiny bit, set the pan aside. Note the position of the filter to aid in installing the new unit. Then, remove it by gripping it firmly and pulling down while twisting a bit. Discard both filter and filter seal. If the seal is stuck up in the valve body, pliers will usually pull it out. Remove all traces of the old gasket from the transmission case and pan. If a significant amount of the gasket is stuck to the pan and you have a quarter-inch-chuck, die grinder, a great way to remove it is with the Gasket Removal Kit from Standard Abrasives Motorsports Division. This kit contains abrasive discs that fit on the die grinder and will quickly remove gaskets but not harm the pan. Because of the threat of gasket and abrasive particles getting into the transmission do not use those discs to remove gasket material from the trans case. That you will have to do with a scraper.

Obtain an ACDelco trans filter kit (p/n TF306). Install its new filter seal in the valve body then push the new filter in place. Clean out the trans pan and look closely at its bolt washers. Their flat sides go towards the pan. If they are reversed, get new bolts. If they are not reversed, reuse the bolts. Apply the new gasket to the pan. Install the pan and torque the bolts to 8 ft/lbs.

Add fluid until it leaks out, then install the fill plug. Perform the fluid check procedure discussed earlier and, if necessary, add more fluid. Since 1994, the factory-fill fluid in Corvette automatics has been an organic-based ATF meeting the Dexron III specification. A suitable performance upgrade would be a switch to or Red Line Oil's D4 Synthetic ATF or Mobil 1 synthetic fluid.
Ok but where is the fill plug hole ?
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Old Mar 16, 2007 | 10:57 PM
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Originally Posted by 1Sonny
Ok but where is the fill plug hole ?
It is on the drivers side of the pan.
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Old Apr 21, 2007 | 07:53 AM
  #6  
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Thank you dcblackc5! Going to put it on a lift in a little while, and wanted to check the ATF while under there.


Tim Glover
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