Detroit question

foreman1063

foreman1063

Well-Known Member
Joined
Jul 11, 2005
Location
Raleigh
Got a new Detroit installed with 4.56 gears in a TJ D44. Went for a spin around the yard and am hearing some odd noises. Trying to determine whats normal since I've always heard Detroits are noisy. Seams to be some clunking when going from reverse to forward and vice versa. Also how much play should be in the drive shaft? I can grab the drive shaft and turn about an 1/8 of a turn before stopping. Just trying to determine if everything is cool before driving too far.
John
 
John, my detroit does not make any noise although I have heard once in a while you can get them in a bind and they will unload and sound loud. I have about the same movement in my shaft, check the clearance on the gears and they are perfect so I assumed the detroit allows for more lash than expected. I was reassured that this is normal.

No idea what the noises are though. With club packs it should be quiet for the most part I thought.
 
foreman1063 said:
Got a new Detroit installed with 4.56 gears in a TJ D44. Went for a spin around the yard and am hearing some odd noises. Trying to determine whats normal since I've always heard Detroits are noisy. Seams to be some clunking when going from reverse to forward and vice versa. Also how much play should be in the drive shaft? I can grab the drive shaft and turn about an 1/8 of a turn before stopping. Just trying to determine if everything is cool before driving too far.
John
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Sounds like it's working fine. :D Do you have an auto?
 
Autos are quieter because it keeps pressure on the gears more often than a stick shift does. So long as the transmission is in gear, the torque converter is always pushing a little bit and keeping the gears snugged up. The gears will roll to the coast side under closed-throttle decel, but it still cushions the movement comparatively.

A stick shift goes completely slack (or rolls all the way to the coast side) every time you get in and out of the gas, change gears, etc etc. So it feels a lot more loose, makes more noise, feels more twitchy in turns, etc.
 
Here's a great picture of a detroit. Notice the dog gears at the center of the detroit -- the gaps in those gears are the reason it feels loose, and the reason the driveshaft moves so much before it binds up. They're also the reason it engages quickly and easily, and the reason you can turn a detroit-equipped front diff farther before it binds compared to an ARB or spool (ram-assisted steering aside).
 

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Could you have too much backlash in the gears? I bet that would cause the Detroit to unload and make the gear ping loudly when it snaps back to the coast side of the ring gear. Set your backlash .001 -.002 tighter if you run out of options??? My Detroit make NO noises but its in the front.
 
Thanks for all the good info and pics guys. I feel better about the set up now. Jdubb, not sure what the backlash is set at but will find out tomorrow when I talk to the installer. John
 
Do some internet searches for ring and pinion setup and you'll find out easy enough. If you had the gears professionally setup, it SHOULDN'T matter. But it is not real hard to check yourself. Backlash is the play between the teeth and can be anywhere from .008 to .012 sometimes. I know dirt trackers set they're gears up tighter, or is it looser?, whatever. You might even try some thick and sticky Lucas additive if there nothing mechanically wrong. Just some quick ideas... But turning the driveshaft 1/8 turn by hand?
 
jdubb said:
Just some quick ideas... But turning the driveshaft 1/8 turn by hand?
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That's pretty close to normal.

I wouldn't recommend changing the backlash in the R&P. If your gear guy knew WTF he was doing, it's set up properly.
 
Now that I think of it, I have a Detroit question too. I wanted to run some of Warn's hub fuses in my Dana 44 but the instructions claim they will damage a Detroit when they fail. I am having a hard time believing the hub fuses would do anything to a Detroit. I mean its the same thing as breaking an axle and I'm sure that has never happened. Is this just Warn covering their butts?
 
detroit

Best advice I have for Detroit Lockers is to use something else. I have broken three, they are expensive, it takes forever to get one replaced under warranty(if your real lucky), and their customer service sucks.:driver:
 
jdubb said:
Now that I think of it, I have a Detroit question too. I wanted to run some of Warn's hub fuses in my Dana 44 but the instructions claim they will damage a Detroit when they fail. I am having a hard time believing the hub fuses would do anything to a Detroit. I mean its the same thing as breaking an axle and I'm sure that has never happened. Is this just Warn covering their butts?
Click to expand...

The shock load of breaking an axle alot of time will break off teeth of the detroit. I am sure the hub fuses could case this, too. I wouldn't purposly weaken my drivetrain using the hub fuses. Just keep the joints and hubs the weak link.
 
My only problem is, if something breaks, is this Detroit up to it? I mean, regardless of whether its a hub fuse or u-joint its going to possibly damage the Detroit? I thought they were the strongest thing out there.
 
The one I have in my AMC 20 made more noise when it was first installed and now is better with 20k on it. sometimes it will "bang" when it unlocks usually when I back up and go foward while changing direction i.e 3 point turn with moderate skinny pedal.
 
My last jeep had front and rear Detroits with a 5 speed. It would bang loudly just about everytime I stopped somewhere that invloved turning in. It would also buck like a bronco under neutral throttle. I now have an auto and you wouldn't know there was a Detroit in the rear if you didn't hear the tires chirp a little in a tight turn. There's a bigger jolt going from park to drive too that results from that backlash.
 
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