bryant313 Posted July 7, 2011 Report Share Posted July 7, 2011 so i dropped out the 3 speed automatic transmission out of my 720. i dropped in a 5 speed with a new clutch kit. i had to wire the park/neutral wires together to make it start. the problem im having now is when ever the truck is in gear or in neutral (without the clutch pedal pressed to the floor) it makes a slight knocking sound. it never made that sound when it was in the other truck. i filled the 5 speed with 85-140 oil. i was reading in my haynes manual about a top gear switch. i have never heard of that before and what does it do? could that be making the knocking sound in the tranny? Quote Link to comment
MicroMachinery Posted July 7, 2011 Report Share Posted July 7, 2011 Throwout bearing? Quote Link to comment
ggzilla Posted July 7, 2011 Report Share Posted July 7, 2011 Top gear switch makes no noise. It is to retard the timing to lower emissions. Perhaps your transmission is hitting the exhaust pipe. Quote Link to comment
Hardwyre Posted July 7, 2011 Report Share Posted July 7, 2011 Get a stethoscope and a low profile under-car creeper. Find a flat street with decent pavement and secure yourself under the car/truck while laying on the creeper. Have your friend drive it up and down the street until you either locate the source of the sound or get your clothes yanked up into the driveshaft and die one of the more grusome deaths known to man. Simple! 1 Quote Link to comment
wildmaninid Posted July 7, 2011 Report Share Posted July 7, 2011 Lol, giving a newbie, from las vegas noless, advice like that is a great way to have epic lulz, and get to see that shit on the news! Quote Link to comment
Jayden71 Posted July 7, 2011 Report Share Posted July 7, 2011 Get a stethoscope and a low profile under-car creeper. Find a flat street with decent pavement and secure yourself under the car/truck while laying on the creeper. Have your friend drive it up and down the street until you either locate the source of the sound or get your clothes yanked up into the driveshaft and die one of the more grusome deaths known to man. Simple! WOW!!! I hope you are not speaking from personal experience here :lol: :lol: Quote Link to comment
Hardwyre Posted July 7, 2011 Report Share Posted July 7, 2011 WOW!!! I hope you are not speaking from personal experience here :lol: :lol: I die like a boss. Quote Link to comment
Sealik Posted July 7, 2011 Report Share Posted July 7, 2011 Does the sound go away when you push the pedal to the floor???? If the sound does go away...could be input or counter shaft bearing....or Pilot(new) bushing installed? Quote Link to comment
bryant313 Posted July 7, 2011 Author Report Share Posted July 7, 2011 Does the sound go away when you push the pedal to the floor???? If the sound does go away...could be input or counter shaft bearing....or Pilot(new) bushing installed? yea the sound goes away when i push on the clutch pedal. it never made that sound before when it was in the other truck Quote Link to comment
Sealik Posted July 8, 2011 Report Share Posted July 8, 2011 yea the sound goes away when i push on the clutch pedal. it never made that sound before when it was in the other truck Could be a NFG pilot bushing..?????.....but. Did you hang the trannie on the back of the engine before you bolted it up.....that has a tendency of compromising an aged input shaft/bearing....and or. Check the oil drain (magnetic) bung....should start seeing some residual metal if the trannie is starting to go 'south' Quote Link to comment
bryant313 Posted July 8, 2011 Author Report Share Posted July 8, 2011 Could be a NFG pilot bushing..?????.....but. Did you hang the trannie on the back of the engine before you bolted it up.....that has a tendency of compromising an aged input shaft/bearing....and or. Check the oil drain (magnetic) bung....should start seeing some residual metal if the trannie is starting to go 'south' yeah it was kinda hanging on the engine and the tail end was supported by a floor jack. i drained out the oil today and yea there was a very small chunk of metal that was stuck to the magnet. would it be ok to drive for the next day just to get to work and back which is a total of 8 miles? Quote Link to comment
ggzilla Posted July 8, 2011 Report Share Posted July 8, 2011 sure, it'll usually go for years. A small chunk in the oil is not unusual... Quote Link to comment
datzenmike Posted July 8, 2011 Report Share Posted July 8, 2011 yea the sound goes away when i push on the clutch pedal. it never made that sound before when it was in the other truck When clutch is engaged, peddle up, the release bearing is not spinning and the input shaft and pilot bushing are 'mated' and turning together. When the clutch is depressed the input shaft stops spinning but the release bearing is under load and spinning. 'Sounds' like a bearing. Try driving in 4th under load. If quieter than the bottom three then it could very well be the bottom front counter bearing. If still noisy it could be a mainshaft bearing. Either way this isn't going away. Check oil level? Should be level with fill hole. Quote Link to comment
bryant313 Posted July 8, 2011 Author Report Share Posted July 8, 2011 When clutch is engaged, peddle up, the release bearing is not spinning and the input shaft and pilot bushing are 'mated' and turning together. When the clutch is depressed the input shaft stops spinning but the release bearing is under load and spinning. 'Sounds' like a bearing. Try driving in 4th under load. If quieter than the bottom three then it could very well be the bottom front counter bearing. If still noisy it could be a mainshaft bearing. Either way this isn't going away. Check oil level? Should be level with fill hole. yeah then its got to be the counter shaft bearing. it defently doesnt make any noise in 4th Quote Link to comment
datzenmike Posted July 9, 2011 Report Share Posted July 9, 2011 All gears but 4th have to have power transmitted through the counter shaft. If it's the front counter bearing this is a fairly easy fix. You can remove the front case with a pair of snap ring pliers (if you are careful/skilful a small screwdriver will get it out) and a 12mm wrench. A medium small gear puller will pull the bearing off and a sledge and block of wood to hammer the new one on. If the rear bearing in the adapter plate then it's a bit more involved. This is the front counter bearing Here's a bad one that was in a diesel 720 5spd that I took apart. I have removed the drain plug with the magnet on it and found ball bearings stuck to it. To prevent this, simply replace the tranny oil every 3-5 years and down shift to 4th to pass, climb steep hills and if towing. . Quote Link to comment
bryant313 Posted July 9, 2011 Author Report Share Posted July 9, 2011 All gears but 4th have to have power transmitted through the counter shaft. If it's the front counter bearing this is a fairly easy fix. You can remove the front case with a pair of snap ring pliers (if you are careful/skilful a small screwdriver will get it out) and a 12mm wrench. A medium small gear puller will pull the bearing off and a sledge and block of wood to hammer the new one on. If the rear bearing in the adapter plate then it's a bit more involved. This is the front counter bearing Here's a bad one that was in a diesel 720 5spd that I took apart. I have removed the drain plug with the magnet on it and found ball bearings stuck to it. To prevent this, simply replace the tranny oil every 3-5 years and down shift to 4th to pass, climb steep hills and if towing. . awesome right on thanks a bunch brother! Quote Link to comment
bryant313 Posted July 12, 2011 Author Report Share Posted July 12, 2011 awesome right on thanks a bunch brother! hey i forgot ask you but if i dont hook up the top gear switch will it affect the performance? Quote Link to comment
ggzilla Posted July 12, 2011 Report Share Posted July 12, 2011 Yes, it should run better performance if you bypass the switch. Unless it is used for the fuel-cut solenoid. some datsuns do that. In which case bypassing it will hurt the fuel economy. Your owner's manual will probably say what it is for (read the emissions section). Quote Link to comment
bryant313 Posted July 12, 2011 Author Report Share Posted July 12, 2011 Yes, it should run better performance if you bypass the switch. Unless it is used for the fuel-cut solenoid. some datsuns do that. In which case bypassing it will hurt the fuel economy. Your owner's manual will probably say what it is for (read the emissions section). [/quot i installed a weber 32/36 so i defiantly know that its not gonna effect the fuel cut off solenoid but lets say i do hook it up what wires would i hook it up to since i swapped out my automatic for a manual Quote Link to comment
Sealik Posted July 13, 2011 Report Share Posted July 13, 2011 I doubt the top gear switch affects the idle cut solenoid. I believe the ICS is only utilized on deceleration and engine shut off. I was going to install a switch in 1 of my trannies and see which gear it trips....but...never got around to it. Assuming it would be 5th though Maybe the switch diverts vacuum to the vacuum advance, on the distributor.... in high/top gear only???? Have those wires unplugged and or on a few trucks...no diff. Quote Link to comment
bryant313 Posted July 13, 2011 Author Report Share Posted July 13, 2011 I doubt the top gear switch affects the idle cut solenoid. I believe the ICS is only utilized on deceleration and engine shut off. I was going to install a switch in 1 of my trannies and see which gear it trips....but...never got around to it. Assuming it would be 5th though Maybe the switch diverts vacuum to the vacuum advance, on the distributor.... in high/top gear only???? Have those wires unplugged and or on a few trucks...no diff. yea i didnt think it would make a difference. i cant wait to get this baby back on the road Quote Link to comment
datzenmike Posted July 14, 2011 Report Share Posted July 14, 2011 The early fuel shut off system uses a vacuum switch (to sense high manifold vacuum when decelerating) a clutch switch so it can't operate when the clutch is being used and stall the motor, a neutral switch (same but with the clutch out). Later ones added a throttle position switch. I don't think the top gear switch is used at all. Quote Link to comment
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