14 bolt driveshaft play?

[Javin]

hey I have a 14 bolt ff in the rear of my truck and I was just curious when the emergency brake is on and I put the truck in neutral, I have about a 1/5 of a turn on the drive shaft back and forth like counterclockwise and clockwise? Is this normal, it operates good but it reminds me of a lunch box locker I put in my old trick and it had lots of slop in it.

 

[1987 GMC Jimmy]

I’d check the U Joints just to be safe. They maybe on their way out the door and just haven’t started clunking yet. Honestly, not the likeliest, but things get progressively more complex from there. It might be a backlash issue. The best thing to do would probably be to drain the diff., pull he pan, spray down with Brakleen, and inspect the wear pattern on the ring gear. It can be quite telling of what the situation is.

https://www.racingjunk.com/news/2015/03/24/how-to-set-up-your-rear-gear-correctly/

You must be registered for see images attach

 

[bucket]

Likely just a little slop in the spider gears. A slight amount of wear in everything can add up to a lot of slop at the driveshaft.

 

[Javin]

Yeah the u joints have no play, I’m thinking more the back lash, but there is no noise or any vibrations and I’ve had the truck for 2 years and it’s had the same amount of slop

 

[Dutch Rutter]

Last week I had my truck in a good drive line shop for this plus a loud clunk and jerking motion when the trans shifted from 2-3 and I happened to let off the throttle. I thought backlash.
They found some play in the spider gears, not enough to do anything about he said. He then told me that my np208 has some play and is most likely my culprit, it will be getting rebuilt sometime down the road. Just something to check out as well.

 

[nvrenuf]

My money says the axle is fine, there can be a lot of opportunities for slop in an axle without it being bad.

To get the best feel you'll need to disconnect the driveshaft and really get comfortable by the yoke. Rotate the yoke by hand the full about of the slop (the 1/5 turn you described), now carefully rotate it less and feel for a very small amount of slack - this should be your backlash. Do this a few times and you'll learn to the feel the differences in the slop. Chances are the backlash slop is more like a 1/16" of rotational movement of the yoke. The full 1/5 turn you're feeling / seeing is likely the total combined slop of the r&p backlash + spider gear slop + inner axle shaft spline slop. If there is any kind of limited slip or locking diff they can add to the slop as well. You'd have about 1/4 turn of slop if you had a Detroit Locker. LOL

 

[Javin]

Hey thanks for all the info yeah I’ll have to put her in the air and have a look at it a bit more closely, I think she’s ok but I would like to know at least where the slop is coming from