- Joined
- Feb 21, 2015
- Messages
- 29
Hello, first time posting hear. I've been a member for a long time but sold my first un-finished bronco when i went to college a while back. I just bout this rig about a week ago. I've driven it over 6hrs already around 55mph. Right before I got the 39.5" super swampers off I started getting this humming noise. It also sprung an oil leak somewhere but I'm not sure if that's related as it seems to be the valve covers.
So here is my issues. In 3rd or 4th gear i get this humming noise and maybe a little vibration. As soon as I let off the gas the noise stops and if I push the clutch in the noise stops. Brakes don't seem to make a difference In noise. Makes the same noise in 4hi, 4 lo, and 2hi. It's not as bad in 4low due to lower speeds I'm thinking. It specifically sounds the worse right when your about to let off the gas or if your lugging it a bit in a higher gear and trying to get up to speed. So far I changed the oil in my engine, transmission, and transfer case and they didn't show any signs of excessive metal and had appropriate levels.
Then I took the rear drive shaft out and drove it in 4hi and the noise was gone. This leads me to think its the rear end somewhere. The driveshaft seemed fine when it was off but I'm no expert. So I greased it up( has greaserts) and put it back on. The noise is still there with no change so the greasing didn't do anything so probably not the drive shaft. The rear diff is a 1977 9" out of a f100 and it has a full spool in it.
lastly I jacked up the rear end and spun the wheels and the pass side drum seems to be rubbing or something and there is more play on that side. I'm waiting on a spline drive set( has special lugs) and then i will take the tire off and see if the drum is all blown up or something and if not then I will take apart the rear diff and change fluids/ inspect.
I also noticed that when I jack the front end up with the lockers off and in neutral the tires are hard to turn even with two hands so not sure if that's normal or if the brakes are dragging? It has a Detroit true trac lockers in the front in a dana 44. Also not sure if the dragging brakes could be the issue because the symptoms don't really line up.
The noise started before the tires were changed so I'm confident it's not the tires. Also the brake system sucks and it could be that and if that's the case then I will know once i install the hydro boost from toms. I have video's of the sound if anyone thinks that will help diagnose. I'm swinging by a driveline shop tonight to see what they think after I run a couple more tests. The bronco was used as a plow with those giants 39.5" tires so not sure if that cause excessive strain and the mileage on the road is what did it in. It sat barely being used or moved for aprox 12 years
My question is what does the issue seam to be? I feel I have crossed off many things that could be the issue but to me it seems its one of four things
1: rear axle bearing
2: pinion bearing/gear
3: rear drum brakes
4: transfer case( although shouldn't this make noise still with the rear driveshaft off)
Also here is the general driveline setup if that helps
1990 ford f150 302
1977 ford f100 np435 with 4 speed manual hooked up to a np205
custom driveshaft with double cardan u joint in the front by t-case then normal in rear hookup to diff( same in the front)
9" rear diff with 4.56 gears and full spool and drum brakes in the back
dana 44 in front with Detroit true tracs in front and disc brakes
So here is my issues. In 3rd or 4th gear i get this humming noise and maybe a little vibration. As soon as I let off the gas the noise stops and if I push the clutch in the noise stops. Brakes don't seem to make a difference In noise. Makes the same noise in 4hi, 4 lo, and 2hi. It's not as bad in 4low due to lower speeds I'm thinking. It specifically sounds the worse right when your about to let off the gas or if your lugging it a bit in a higher gear and trying to get up to speed. So far I changed the oil in my engine, transmission, and transfer case and they didn't show any signs of excessive metal and had appropriate levels.
Then I took the rear drive shaft out and drove it in 4hi and the noise was gone. This leads me to think its the rear end somewhere. The driveshaft seemed fine when it was off but I'm no expert. So I greased it up( has greaserts) and put it back on. The noise is still there with no change so the greasing didn't do anything so probably not the drive shaft. The rear diff is a 1977 9" out of a f100 and it has a full spool in it.
lastly I jacked up the rear end and spun the wheels and the pass side drum seems to be rubbing or something and there is more play on that side. I'm waiting on a spline drive set( has special lugs) and then i will take the tire off and see if the drum is all blown up or something and if not then I will take apart the rear diff and change fluids/ inspect.
I also noticed that when I jack the front end up with the lockers off and in neutral the tires are hard to turn even with two hands so not sure if that's normal or if the brakes are dragging? It has a Detroit true trac lockers in the front in a dana 44. Also not sure if the dragging brakes could be the issue because the symptoms don't really line up.
The noise started before the tires were changed so I'm confident it's not the tires. Also the brake system sucks and it could be that and if that's the case then I will know once i install the hydro boost from toms. I have video's of the sound if anyone thinks that will help diagnose. I'm swinging by a driveline shop tonight to see what they think after I run a couple more tests. The bronco was used as a plow with those giants 39.5" tires so not sure if that cause excessive strain and the mileage on the road is what did it in. It sat barely being used or moved for aprox 12 years
My question is what does the issue seam to be? I feel I have crossed off many things that could be the issue but to me it seems its one of four things
1: rear axle bearing
2: pinion bearing/gear
3: rear drum brakes
4: transfer case( although shouldn't this make noise still with the rear driveshaft off)
Also here is the general driveline setup if that helps
1990 ford f150 302
1977 ford f100 np435 with 4 speed manual hooked up to a np205
custom driveshaft with double cardan u joint in the front by t-case then normal in rear hookup to diff( same in the front)
9" rear diff with 4.56 gears and full spool and drum brakes in the back
dana 44 in front with Detroit true tracs in front and disc brakes
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