Heard grinding noise, thought it was from rear drive line

Glad to see the Jeep Medic is still at this site. You've helped me a couple times before. I checked the transfer case, both shifters were in the correct position. I engaged them and returned them to their correct position earlier. When I engaged the wheel locks both appeared to be disengaged. They are quarter turn Superwinch wheel locks. I haven't disengaged them from yesterday. I'll disengage them tomorrow and let you know what sounds I get.

FYI: some background on my jeep: I do some DIY, some shop, engine was built by Precision Engine in Houston, 9: 1 compression 204/214 @.050 cam, Thorley tri-Y exhaust headers, 2" dual exhaust w/crossover no Cat, Edelbrock performer intake, Edelbrock Thunder series AVS 650 cfm carb with electric choke. Carb is still factory set and a little rich, true idle speed 800 rpm when warm. New mechanical fuel pump, diaphragm booster fuel pump by the tank (cured the vapor lock), recent fuel filter, new wires, plugs, cap rotor, high flow water pump and high flow thermostat, new belts, hoses, etc. Davis Unified Ignition, power steering, power brakes with dual diaphragm upgrade, four speed rebuilt Tremac 176 transmission, rebuilt Dana 300 w 4:1 low range w/ JB Custom split shifter, New “U-joints” on rear driveline, AMC 20 rear end with Summers brothers nickel chrome-moly axle & welded tubes 33x10.5-15 s on American Racing wheels. Hayes clutch and flywheel when rebuilt. Has ARB air lockers front and back, 4:11 dif, sway bar disconnects, 2 � inch lift, etc... The vacuum advance is connected to the carb the PVC is still intact the rest of the pollution gear is gone, no pollution inspection required & none installed. PS: I'm the original owner.

By the way, when I said wheel locks I meant that I was engaging my locking hubs

I unlocked the hubs, drove 1 mile, small undulation in the road and the noise and minor vibration came back. Noise is there when steering, straight line, accelerating and deaccelerating. I tried locking just the left locking hub and the noise quit. Then my wife got mad that I wasn't taking care of the yard work so I changed focus. I did try to rock the wheels side to side, they don't. U-joints on the front are as tight as the new ones on the rear drive shaft. Then I got another visit from my wife. I'll check more tonight.

Figured you meant the steering U-joints, as the others shouldn't have been turning if the wheel locks disengage; but I was there. Its screaming hot outside, its a Texas thing. I put the jeep on jack stands first thing in the morning, check for disengagement and looseness. I'll send out a note first thing in the morning. I'll post a picture as well.

Jeep is up on the jack stands, hubs unlocked. Drivers side steering U-joint doesn't turn with the wheel, conversely wheel doesn't turn when manually turning the steering U-joint. Oddly enough the passenger side steering U-joint turns with the wheel in either direction as well as the wheel turns with the U-joint.

I've looked on line for rebuild parts for the superwinch locking hubs. Couldn't find any. They were a replacement for the plastic warn hubs that were OEM. I'll probably just replace the hubs. Never heard of Selectro locking hubs, I'll have to look them up, I get a discount with 4WD, I'll see what they and Summit Racing have. Thanks for your help.

Never noticed the gas mileage drop, aerodynamics of a brick, lift kit, large tires, 4.11 gears, and a V8, hmmm.

Seems they, Mile Maker, doesn't make the Selectro for the Dana 30 on a 1980 CJ7. I can find the Warn Premium, Mile Marker 457, Rugged Ridge and Crown. I've never had anything from Crown that fit without modification so they are out. Any preferences with the others?

I'll check them out, thanks for the help. By the way, I love your Willy's, sweet.