Can i flip my rear driveline?

[y5mgisi]

On my 78 k20. It's a standard driveline with the slip about a foot from the end near the transfer case. I want to put that end at the axle for more ground clearance and also to see if it helps with my vibration on the highway. so is it ok to flip them?

 

[Fordum]

I kinda did it with my '79 F150. I had had to replace the slip joint for the second time. It would wear a ridge in the splines and bind when coming to a stop.
Mine was near the rear end from the factory.
I had the driveshaft shop reverse everything so that the spline was next to the transfer case.

I don't remember at this late date if there was anything else that had to be done. I suspect that both ends were the same.
On my '89, the ends are different since I am running a different transfer case from stock.

In my case, it solved the problem. Getting the spine up out of the dirt and mud stopped me from ever having to replace it again.

In your case, since you don't go through the knee deep mud I do on a regular basis, it might work OK.

 

[y5mgisi]

I guess it would be worth a shot anyway.

 

[chulisohombre]

i dont think itll make a difference.the ends will still be at the same angles they are now.its best to have the slip up higher to keep it out of the dirt and road debris.its worth trying though and free to do.as long as the yolks are the same size at each end.i take the caps off and chack the needle bearings as well and grease them good to make sure its not a joint problem also.

 

[y5mgisi]

Im thinking im going to just go ahead and put new joints in before i flip it. It does seem like a good idea to keep it up out of the way at the t-case.

 

[y5mgisi]

This is what my vibration seems like. Its the "pace" of a tire vibration but you can see the t-case shifter vibrating at that same pace. So its kina like its between a tire vibe and a typical DL vibe.

 

[y5mgisi]

Forgot to add that it only does it above 50ish MPH.

 

[imiceman44]

Forgot to add that it only does it above 50ish MPH.

I would replace the Ujoints if they are old, and take it and balance it, our driveline shop here charges $15 for balancing it.

 

[y5mgisi]

My shop says $73...

 

[y5mgisi]

But yes, i think i should replace the joints as i have no idea how many miles are on them. They SEEM tight and perfect but you know how that goes.

 

[imiceman44]

My shop says $73...

ouch
Here it cost $50 for shortening a driveshaft and $65 with balance.

Did they quote you that with the price of changing the Ujoints?

 

[y5mgisi]

Nope

 

[Cornfield creations]

Just food for thought. Flipping the shaft backwards, wouldn't that change the rotational torque the shaft has seen it's entire life, possibly twisting the shaft is the opposing direction, and causing it to either A:become unbalanced and cause vibrations or B: fail completely due to stress?

 

[y5mgisi]

The vibes I don't know about. Failing I doubt. It can see full throttle reverse all its life and not have a problem so its probably good there.

 

[y5mgisi]

So, as it turns out, i cant flip my driveline. The u joints are different sizes. Smaller at the t-case. Also took some videos. Im pretty well convinced that the vibe is the passenger rear drum! It totally spins off center. The strange part is that it seems to have developed this vibe over time. All very strange. But i did several scientific tests. more to come...

 

[K85 Octane]

I was just going to say, "only if the u joints are the same". A lot of the driveshafts I've seen lately have the slip at the axle end. My new tom wood cv shaft is that way too.

If I considered the pros and cons, I think the slip is better at the bottom. When the suspension goes through it's travel (on or off road) it would seem you want any tension from the slip to be near the suspension, not the T-case. You want it flexing as quick as possible and not having to travel up the shaft, adding leverage as it move away from the suspension, towards the T-case. Protecting the slip is the only drawback.

Just my thoughts, still warm from inside my rectum.

 

[y5mgisi]

So heres what happened today trying to find the source of my vibe.
Put the rear end on jcak stands and ran the truck up to 55. Vibes.
Pulled the tires and ran it up to 55. Vibes.
Pulled the driveline and tried to flip it but couldnt so i cleaned and reinstalled it. Back up to 55. Vibes.
Noticed the off center drum.
pulled the axle shafts. Back up to 55. No more vibes.

So, it appears the drum is my problem. Funny thing is it has developed this problem has developed over time... Thinking disc brakes might be in my future.

 

[y5mgisi]

Vids.

 

[chulisohombre]

that is pretty bad.no wonder it was wobbling.if you swapped in the rear 14 b it would have 1350 and the stock shaft would more than likely be 1310 at the transfer case for 1/2 ton.so it may be a conversion joint at the axle.ive had 2 of those go out too.i want to replace my yolk on the driveshaft axle end to have a solid 1350 joint instead of the conversion joint.glad you figured out what it was.you will have some work ahead of you and be cheaper and lighter in the long run to switch to rear disks.those drums are stupid heavy.it saves almost 150 pounds i believe.

 

[mudbuggy]

I've got that same vibration. From 50ish to 65 not large just enough to be annoying. I finally got some time to look and it seems that my transmission mount has seen better days. I know that the u joints are good with no play. Hope this is helpful.