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Doing a little discovery work

B

Bbs383ci

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About a month ago I noticed a knocking noise when I would accelerate from a stop, sounded like it was coming from the front diff.
Had a little time today to explore.

One of the u-joints on the front driveshaft is toast.
2CD1A7CE-6C9D-4828-A5B2-DE9649E68031.jpeg 33F3C634-1483-43B3-B99E-3619C2E14331.jpeg

But would like some input on the front diff. Seems to me that there is excessive back lash in the gears. I know the ideal way to check backlash would be with an indicator on the ring gear directly. Probably going to pop the cover off and do a visual till I can get back to work to get my indicators. Here’s a short video of it.

Is there a better way to post videos from a phone?

 
play looks nornal for front with open spider gears and 2 shafts and 2 u-joints and 2 locking hubs all added up in the mix .

but a pull of the cover to verify and know what you have and fresh gear oil is a good thing .
 
Sweet! Thanks. I will be looking inside hopefully Sunday evening.
 
Most of the play between when you change pinion direction and the axleshaft(s) turn is in the spider gears. The actual ring/pinion backlash is much more subtle and maybe impossible to judge from the outside. Slop in the spider gears is normal and isn't really a problem - the clunk dropping into gear is just annoying.

If you do want to pop the cover and measure backlash you may be able to get the spiders in a neutral position that doesn't interfere. The best way to check it is with axleshafts removed, but that requires a lot of front end tear down
 
Bumping this thread with some discovery work of my own. This is the opposite end though, 14b ff.

Yoke has a about 35° rotational play. Post 2 and 4 here would explain it if it applies, because there is no discernible play in yoke and ring gear, so hoping post 5 is my case too.

I ask because I have 2 other 14b ff and a dana 70 and they only measured about 5° rotational play.

Thoughts?

Pics of diff, I don’t think there is anything special going on there.

7B2C5984-F478-4316-9433-6D934C9909BE.jpeg


BF744A65-3366-4876-84FE-BA7CF301A59E.jpeg

9B08774A-2A4C-402E-9EBB-8E5D93982F7F.jpeg

477A8E23-2AB6-4695-9739-AE06E1EF78A2.jpeg
 
35* is not good at all. Warn out gears if bearings are not slopping. Even if they were, the gears will be bad by now. That is a full rebuild.
 
It probably has a Detroit Locker in it. They do have some slop built into them, which is multiplied by the gear ratio. https://ck5.com/forums/threads/detroit-slop.344074/

From the Eaton FAQ:
This happens because Eaton Detroit Lockers have “backlash” or “slack” between the drive and driven teeth and you will hear this in everyday use going through corners and when transitioning from drive to coast. Also, with the vehicle on the ground and the transmission in neutral, several degrees of lash in the driveshaft is normal. Here is a formula to calculate the degrees of rotation of the driveshaft: (differential internal lash X ring and pinion ratio) + ring and pinion backlash + driveline slop such as U-joints wear.
Click to expand...

For the 14B FF, the Detroit installs inside an open carrier, kind of out of sight. You may be able to spot that it's a Detroit and not spider gears through one of the holes. Also, you can test the locker operation by spinning the tires in different directions, etc.
 
Truckman4life said:
Are you holding the diff from moving at all while measuring this amount of play?
Click to expand...

Tires are on the ground, no movement there.

I can make the yoke turn the same amount of degrees by moving the ring gear with the diff cover removed.

Does this answer your question?
 
joshuak said:
Tires are on the ground, no movement there.

I can make the yoke turn the same amount of degrees by moving the ring gear with the diff cover removed.

Does this answer your question?
Click to expand...
To truly isolate ring and pinion backlash you need to hold the ring gear solid and then check yoke play. I usually use a hammer handle and pry it against the ring gear while checking the play. As stated above the locker or spider gears and play on axle shafts can all add together to make it look like way more play than just the gear backlash.
 
Blue85 said:
It probably has a Detroit Locker in it. They do have some slop built into them, which is multiplied by the gear ratio. https://ck5.com/forums/threads/detroit-slop.344074/

From the Eaton FAQ:


For the 14B FF, the Detroit installs inside an open carrier, kind of out of sight. You may be able to spot that it's a Detroit and not spider gears through one of the holes. Also, you can test the locker operation by spinning the tires in different directions, etc.
Click to expand...

I'd read over on the thread linked bellow that Detroit Lockers can have some amount of slop to them. But my diff sure looks like the one TJ1978 posted and it was decided that his was/is an open diff, I honestly can't tell from looking at the pics, I have heard it chirp when going around corners though.

https://ck5.com/forums/threads/clunky-rear-end.346793/

Checking out the thread you linked, thanks.
 
Truckman4life said:
To truly isolate ring and pinion backlash you need to hold the ring gear solid and then check yoke play. I usually use a hammer handle and pry it against the ring gear while checking the play. As stated above the locker or spider gears and play on axle shafts can all add together to make it look like way more play than just the gear backlash.
Click to expand...

I didn't take a measurement, but there was no play that I could feel in the yoke when I held the ring gear in place and tried to rotate.

I'll try and get some numbers to go with my feel later.
 
joshuak said:
I'd read over on the thread linked bellow that Detroit Lockers can have some amount of slop to them. But my diff sure looks like the one TJ1978 posted and it was decided that his was/is an open diff, I honestly can't tell from looking at the pics, I have heard it chirp when going around corners though.

https://ck5.com/forums/threads/clunky-rear-end.346793/

Checking out the thread you linked, thanks.
Click to expand...
Look at the spider gear showing on his diff - open.

TJ open diff.png

Now look at yours...
 
That explains it, thank you for pointing that out and learning me something today.

For future reference here’s a slightly better picture than I posted previously.

8256FECD-00DE-4C4B-A224-6AD05E68060E.jpeg
 
Like mentioned above, Detroit and open ARE the same differential case. You open the stock carrier, remove the spider gear stuff, put the Detroit in and re-assemble.
 
10-4. Certainly is clear as mud when you know what you’re looking for.

It appears that I have what tarussell calls the good kind of rear axle slop!

tarussell said:
... a No-Spin ( Detroit Locker ) in your open diff - just say’n…
That would create the “good” kind of rear axle slop !
Click to expand...

Thanks for the help guys.
 
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