Axle & Noise Identification

[J-Ro]

Hi Guys,

I recently bought a 2wd 94 Ranger. I bought the truck for cheap with no engine or transmission in the thing so I wasn't able to drive it.

The previous owner had lowered it a bit and in the process he put in what he says is a "8.8 3.73 LSD Disk Brake Rear End from an explorer". He weekend drag raced the truck with a turbo'd 2.3L of unknown power level and was his daily driver during the week. He also says the rear end only has 2,000 miles on it since new bearings and seals were put in it.

1) How can I tell what year this rear end is from? Its going to need brakes soon and I dont have any idea what to buy for it.

2) When I am going in the area of 50mph and higher and I remove my foot from the throttle I get a fairly loud grinding/vibrating/ratttling type sound. None of those words individually properly describe the sound but its somewhere in the middle of those sounds. I hear the sound if I am in gear, out of gear, clutch in & clutch out. It really just seems to be speed based. The faster I go the louder the sound is. When I am going approximately 45mph, if I listen hard, I can maybe pick out the sound but its mostly not there. The sound goes away the instant I give it any amount of throttle.

I initially thought it might be transmission becasue the sound sure seems to be coming from the direction of the firewall but the way the sound seems to be there regardless of the gear i am in or not in makes me think maybe its rear end noise.

Any ideas on what might be making this sound? What are some things I can do to help pin-point its source?

Thanks!

 

[Explorin94]

Sounds like the rearend needs to be rebuilt and the ring and pinion need to be reshimmed. Explorers started the disc brakes in 96 and they were pretty much the same until the new body style came in.

 

[mattging94]

There should be a tag on the differential cover of the axle that will tell you exactly what year it was made and what gear ratio it has. Looks like this:

As for your noise problem, it could be either something in the axle or possibly the U-joints on the driveshaft or the output shaft of the transmission - you could try puting the back end up on jackstands and the run the truck up to 50 with the tires off the ground so you can at least try to better pinpoint where the sound is coming from.

 

[4x4junkie]

'95 is when Explorers got the disc brakes, so if it has discs, it's a '95-'01 axle.
Link to page for decoding the tag:
http://www.therangerstation.com/tech_library/Axles.html
Note that the MFG date often can precede the axle's model year by 3-4 months (so if yours decodes to Oct '95, it's quite likely a '96 axle).


Grinding/vibration sounds when letting off the gas could be a loose pinion and/or bad pinion bearings.