14 bolt pinion help

[dstang97]

on my 14 bolt when I put it in to reverse or forward I hear a clunk. The pinion moves 1 inch before it catches I guess the next tooth. I know its not a mount making the noise its the pinion yoke. I had the driveshaft off and with both wheels on the ground when I checked. Any got any answer before I pull the cover?

 

[91W350]

Is the pinion nut tight? I had the same concerns with my first Detroit locker, I am betting it is not the ring and pinion at all, but the locker reversing. Glen

 

[taildragger03]

Check the u-joints as well, while your there.

 

[91W350]

I agree to check the U joints, but he said he had the shaft out, the U joints have nothing to do with what he is describing.

Is there another truck around, would you like me to shoot a short video of my M1008? I can neutral the transfer case and roll the shaft for you, that would be simple enough to give you some comparison. Glen

 

[ALFA2]

dstang97, if your 14 bolt pinion rotates about an inch, before contacting other gear teeth, you may need to tale off the diff cover and take a look at the ring gear/ pinion gear.
This is a strong gear set, and does not wear out or break often, even if seriously abused, but can have broken teeth or excessive wear, if water got in and was not drained before damage was done. Take off the rear cover, drain the gear oil, look at it's color, is should not be foamy, or cream like, clean out the gear set with spray cleaner, and you can see the gears mesh when you turn the pinion. By moving the pinion input flange back and forth, you can see if the clunk it made before is repeated, and what is making the clunk. if it it excessive clearance between the gears, they need to be replaced, same for bearings, sometimes the passenger side carrier bearing cap can crack, and become loose, and sometimes the carrier cap bolts get loose causing all-sorts of noises and damage, while still working the gear set.

Hope this helps.

ALFA2

 

[91W350]

Good information, I was not aware of the bearing cap issue. One thing about it, pulling the cover is cheap enough to do and you can get a good look at it. If you turn the pinion a complete turn and set the tires down again, is it the same? I am betting it is just the Detroit.

ALFA2 is correct though, pull the cover and put your mind at ease. I did on my original M1008 and it all looked new at 80,000 miles, but the jail never used it very hard. They pushed a lot of snow with it, but that is a no load operation in comparison to a hard pull or big tires. I have never seen one full of oil fail.

When my buddy was still in the truck salvage business, there was not a large demand for 14 bolts, unless you found somebody wanting a different gear set or an upgrade for a half ton 4x4. Glen

 

[dstang97]

thanks guys I have 2 other 14 bolts so I'll check them and then take off the cover. It just seems there is just to much play.

 

[4bogginchevys]

you can try rotating the pinion back and forth carefully to see if the "lash" is tight and your finding looseness within the carrier. I commonly notice some looseness going into gear if parked on a slope or even with the front wheels turned hard in one direction. The detroit locker does some "ratcheting" to engage, like has been said, if needed pull the cover and inspect while turning the pinion, you can make it ratchet easier while on jack stands. good luck

 

[dstang97]

I put both trucks on the ground both in park but transfer case in nuetral My k30 had about 1/4 inch of play and seemed normal. the D30 moves about 1 1/4 inches. guess I'm pulling it tomorrow.

 

[91W350]

Does your K30 have the Detroit? They have more free play than any other differential I have owned. Glen

 

[dstang97]

no open. You sure I am supposed to move the shaft 1 1/4 side to side. it seems fine driving it down the road no noises or anything. Its late now but tomorrow ill take it off and see whats going on in there.

 

[91W350]

I am betting it is okay. Both of mine are about like you describe. When we put Detroits in the Dana 70s in our M715s, they felt like they would turn a half turn on the shaft. They were not that bad, but being used to a regular differential, we were wondering if we had committed some serious assembly error. After several trips to the rocks, it was obvious that they were really solid. It is even more exaggerated on a 5.89 gear....

Pull the cover and check, it will set your mind at ease and if you find something, it will never get cheaper to fix it than it is now....... Glen

 

[dstang97]

thanks bud

 

[91W350]

Just wait until you catch it just right while backing up and stopping just as it is about to skip into the next locking notch. You drop it in drive and the driveshaft sounds like a bell ringing. I find it is especially bad backing with the front wheels turned right, then taking off to turn left, like leaving my driveway. These M1008s are not as bad as my M715s were, but they will still bang and ring. My Toyota LandCruiser's Detroit was pretty rough too and it was a 4.10 gear. It was set up quite a bit different than the ones in my M715s were. Glen

 

[dstang97]

you know what I just realized everytime it does it its in high Idle. so it must be fine.

 

[Croatan_Kid]

Mine does the same thing, you can turn the driveshaft about half a turn before it engages. Mine will also unlock with a slight load on it while going around a corner...it feels like I broke a gear in my trans, but it's just the Detroit binding and then unlocking. They're weird, but it's just "the nature of the beast"

 

[AJMBLAZER]

Nothing like reversing and turning in a parking lot out of a space and it going BANG and then some "gearhead" going, "YOUR REAR END IS MAKING NOISE!"

"It does that, thanks."