One Piece Driveshaft

[EJH]

So basically what he is saying is it is axle rap slapping the helper spring into the main spring. If that's the case do people who have installed the multi-leaf progressive springs have no or less thump/bump?

Exactly.

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[Superspirit]

I have the TW driveshaft and the global springs and I have the thump bump on stop and start also so I'm thinking i it's normal. My old Silverado 1500 had it also. So I'll believe it could be the spring wrap up. Either way I've decided to ignore it and drive the truck.

 

[Rotortech]

This was an ongoing problem for me, with both the stock driveshaft, and then again with the TW driveshaft. Switching to the correct calcium sulfonate grease in the slip yoke ended the issue for me. Going on a few weeks now since the grease change, and not even the slightest hint of start stop thump. Smooth as butter. (And my commute is lots of stopping and starting) Now I'm totally convinced it was the binding slip yoke I was feeling.

Try putting the transmission in neutral the the next time you're rolling to a stop. This made my thump when stopping disappear. My guess is that there is less twisting force on the driveshaft while braking to a stop in neutral, so the splines are more free to slip as the rear suspension lifts, then settles during the stop.

 

[Superspirit]

This was an ongoing problem for me, with both the stock driveshaft, and then again with the TW driveshaft. Switching to the correct calcium sulfonate grease in the slip yoke ended the issue for me. Going on a few weeks now since the grease change, and not even the slightest hint of start stop thump. Smooth as butter. (And my commute is lots of stopping and starting) Now I'm totally convinced it was the binding slip yoke I was feeling.

Try putting the transmission in neutral the the next time you're rolling to a stop. This made my thump when stopping disappear. My guess is that there is less twisting force on the driveshaft while braking to a stop in neutral, so the splines are more free to slip as the rear suspension lifts, then settles during the stop.

I've tried nuetral, sport and tow mode. None of these have had an effect. I'm a retired ase master tech so I've tried all but changing the grease

 

[EJH]

This was an ongoing problem for me, with both the stock driveshaft, and then again with the TW driveshaft. Switching to the correct calcium sulfonate grease in the slip yoke ended the issue for me. Going on a few weeks now since the grease change, and not even the slightest hint of start stop thump. Smooth as butter. (And my commute is lots of stopping and starting) Now I'm totally convinced it was the binding slip yoke I was feeling.

Try putting the transmission in neutral the the next time you're rolling to a stop. This made my thump when stopping disappear. My guess is that there is less twisting force on the driveshaft while braking to a stop in neutral, so the splines are more free to slip as the rear suspension lifts, then settles during the stop.

I will be lubing again with the grease you linked above. I am just not sure I will bother until next spring. I'm also in Oregon and we only have a short while until temps drop enough for the bump to go away until April or so.

 

[EJH]

I had my Ranger at the dealer today for the bump on stop/start, with kind of mixed results. Some history first:

• I have had the bump on stop start since new. The It was worse when warm.
• Last June I lubed the driveshaft spline joint with Ford’s white single use pouch grease, which helped about 50% or more, especially with the bump when stopping, not as much with the clunk feeling pulling away.
• I recently upgraded to full Fox 2.0 (added front coilovers), which helped reduce the bump on stop more, by reducing overall body motion front to back.

The dealer would not re-lube the spline for me. They reset the transmission adaptive tables. I debated and said it was unlikely to have fixed anything. I ended up having the service manager ride along with me. He was cooperative and knowledgeable, actually a nice guy.

• The thump/bump when I pull away (pushing the gas pedal) seems gone. This could have been a hard shift in the transmission or something tranny related? I can accept the adaptive transmission reset helped here. This feeling pulling away has always felt slightly different than the bump on stopping. It felt more like a gear dropping.
• The thump/bump on stop is still there, at the same level is was before.
  • The service manager, claims this is normal, and not the spline joint. He says it is the little help leaf spring under the main leaf spring making contact when stopping. See my pictures below. A few things he asked me to confirm his theory:
    • Is the bump worse with lighter loads – Yes. I has just removed my RTT two days earlier and the stop bump got more pronounced.
    • Is the bump mostly gone when I have a heavy load – Yes. He says that is because the leaf springs are resting on the helper spring pad 100% of the time.
    • Is the bump worse stopping on downhill instead of uphill – Yes.

The service manager does not disagree that I may have had a binding spline joint on the driveshaft, but I lubed that. What I have been thinking was still a sticky spline joint since my lube job he claims is the rear suspension leaf springs contacting that helper leaf pad. He says all trucks with leaf springs can do this. He says a blinding/sticky spline joint has a different feeling, and you will notice it shifting between reverse and drive.

Like I start off saying, a mixed bag

I’m also curious if what I feel when stopping will change as the weather gets cooler . Lately, I am not noticing a difference at 60’F or 90’F. I wonder if my spline joint I lubed was temperature dependent and the current bump on stop may have always been there, but since it is less that it used to be, maybe it never bothered me during the winter. I won’t know until things cool off consistently here (~2 months from now).

In any case, I plan to re-lube the spline with calcium sulfonate grease next time, out of curiosity. I’d love to try a TW one-piece driveshaft also, just to compare, but not sure I want to spend $700 just for an experiment.

Regarding the rear suspension: If it really is the leaf springs bumping that helper spring, I’m wondering if something like a Roadmaster Active Suspension would lessen the bump I feel on stop? The RAS is basically a helper spring that keeps the leaf springs more extended and taut. I have been debating installed these to help with towing my trailer and hauling heavy loads anyway.

Quick update to this. I relubed my spline with CS Moly and all hints of a bump on stop and start are gone. So the dealer was full of sh!t.

 

[quangdog]

So the dealer was full of sh!t.

I'm shocked!

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