Question on different F150 Slip Yokes

[Rembrant]

Gentlemen,

This might be a stupid question but figured I'd ask anyway. Even though I've changed transmissions, I'm still running the original '84 slip yoke. I don't have a picture of it at the moment, but it is the same as the one in this pic below. The casting is round and it has an external ring mounted like a harmonic balancer. (The whole thing is probably 5 1/2" or 6" OD)

I have another slip yoke here that I removed from a 1996 F150 with an M5OD trans. Pic below. It's hard to read the numbers in the casting, but it looks like E1TW CA34, but could be E1TW CA84?

The purpose of the larger one with the rubber mounted external ring is just a vibration damper? Was it by any chance specific to my truck's original 3spd trans?

I guess my question is...are these slip yokes interchangable? It looks like they likely existed at the same time, so why would one truck have one and another not. (For the record, I'm pretty sure I've seen the larger style with the damper ring on factory 5spd trucks).

Is there a reason one was used over the other?

What say the experts?

[Gary Lewis]

Well, its been 4 hours and the experts haven't shown up. But let me jump in here.

First, I'm trying to determine what the original yoke is, but I don't know what tranny it had originally. It wasn't the M5OD was it? Regardless, from the Application tab at Documentation/Driveline/Driveshafts it looks like an '84 shortbed (116" wb) with a 5.0L and with any manual tranny would take slip yoke #117. And on the Slip & Flange Yoke tab I see that #117 translates to E1TZ 4841-B. And tomorrow I might slip out to the shop and see if I can crossref that to an ID #.

But the MPC doesn't have an E1TW prefix for any yoke. Obviously that the ID # since it is on the part, but sometimes the MPC gives both the part and the ID #. Not this time.

As for why the ring, it is surely just to take out the pulses. And as long as the slip part of the yoke is the same length I don't see why you can't interchange them. So the one with the ring would my choice.

[Rembrant]

Well, its been 4 hours and the experts haven't shown up. But let me jump in here.

First, I'm trying to determine what the original yoke is, but I don't know what tranny it had originally. It wasn't the M5OD was it?

Gary,

Factory trans in my truck was 3spd manual column shift.

Reason I asked was I am trying to really fine tune things now, and get rid of every little vibration in the truck lol. I dropped my driveshaft off today to get balanced (or checked to see if original balance is still OK), and was trying to decide what slip yoke to re-install on it.

 

[Gary Lewis]

Well, its been 4 hours and the experts haven't shown up. But let me jump in here.

First, I'm trying to determine what the original yoke is, but I don't know what tranny it had originally. It wasn't the M5OD was it?

Gary,

Factory trans in my truck was 3spd manual column shift.

Reason I asked was I am trying to really fine tune things now, and get rid of every little vibration in the truck lol. I dropped my driveshaft off today to get balanced (or checked to see if original balance is still OK), and was trying to decide what slip yoke to re-install on it.

I would think the yoke with the ring would dampen more vibrations than the one w/o. And the only very slight downside I can think of is slightly more inertia to accelerate or decelerate. That will cut ever so slightly into your ET's at the strip.

[Rembrant]

I would think the yoke with the ring would dampen more vibrations than the one w/o.

So, interesting...I just picked up my driveshaft from the shop and they said not only was it out of balance, but it was also bent...lol. They straightened it and did a fresh balance. They balanced it with the old slip yoke (with the damper ring) so he said that I might as well leave it on there. However, he said I could stick the other yoke on if I wanted to that it wouldn't make much (if any) difference in what I would feel in the truck.

I was doing some Googling, and it looks like the damper ring was a problem on some later F150's...the rubber would fail and the rings would randomly fall off. Seems most people just cut them off and carried on without them. Makes me wonder how effective they actually were.

 

[Gary Lewis]

I would think the yoke with the ring would dampen more vibrations than the one w/o.

So, interesting...I just picked up my driveshaft from the shop and they said not only was it out of balance, but it was also bent...lol. They straightened it and did a fresh balance. They balanced it with the old slip yoke (with the damper ring) so he said that I might as well leave it on there. However, he said I could stick the other yoke on if I wanted to that it wouldn't make much (if any) difference in what I would feel in the truck.

I was doing some Googling, and it looks like the damper ring was a problem on some later F150's...the rubber would fail and the rings would randomly fall off. Seems most people just cut them off and carried on without them. Makes me wonder how effective they actually were.

The bend and balance issues would certainly cause bad, bad, bad vibrations. Way beyond what the damper could smooth out. Glad you got that fixed.

And I can see that the rubber could deteriorate and cause the ring to come off or slip, which could cause problems. So if that happens cutting the ring off would be an easy fix. Or are you going to change it out now?

[Rembrant]

The bend and balance issues would certainly cause bad, bad, bad vibrations. Way beyond what the damper could smooth out. Glad you got that fixed.

And I can see that the rubber could deteriorate and cause the ring to come off or slip, which could cause problems. So if that happens cutting the ring off would be an easy fix. Or are you going to change it out now?

Well, I've been battling this one vibration at 50mph that has been a real thorn in my side. It seemed to come and go at other times too, but I'm not sure. The roads are rough here a lot of the time, and with the wide tires and short wheelbase...the truck is kind of rough anyway. I've had the wheels balanced three times...once on the inside only, then again on both sides, and then the third time a proper road force balance. Maybe it has been the driveshaft all along, but it sure seemed like it was wheel/tire related. In all honesty, it feels like a tire (or tires) with flat spots...which the Cooper Cobras are somewhat known for on vehicles that sit a lot of the time, which mine does.

Also puzzling...under certain circumstances...I believe if I hit the brakes while coasting at 50mph, then I'd get a fairly serious vibration....like what you would think were warped rotors. However, it rarely happened, so I assumed it wasn't the rotors. Anyway...last week I adjusted the drum brakes, and it seemed to get worse. So, I marched out and bought and installed new drums. The truck did seem smoother, but there was still a shake. That's when I decided to have the driveshaft checked out, and now here I am.

I'm going to install it shortly and take it for a test drive. It's Thursday again, and super nice out, so hopefully there will be a decent gathering for car night.

 

[Gary Lewis]

The bend and balance issues would certainly cause bad, bad, bad vibrations. Way beyond what the damper could smooth out. Glad you got that fixed.

And I can see that the rubber could deteriorate and cause the ring to come off or slip, which could cause problems. So if that happens cutting the ring off would be an easy fix. Or are you going to change it out now?

Well, I've been battling this one vibration at 50mph that has been a real thorn in my side. It seemed to come and go at other times too, but I'm not sure. The roads are rough here a lot of the time, and with the wide tires and short wheelbase...the truck is kind of rough anyway. I've had the wheels balanced three times...once on the inside only, then again on both sides, and then the third time a proper road force balance. Maybe it has been the driveshaft all along, but it sure seemed like it was wheel/tire related. In all honesty, it feels like a tire (or tires) with flat spots...which the Cooper Cobras are somewhat known for on vehicles that sit a lot of the time, which mine does.

Also puzzling...under certain circumstances...I believe if I hit the brakes while coasting at 50mph, then I'd get a fairly serious vibration....like what you would think were warped rotors. However, it rarely happened, so I assumed it wasn't the rotors. Anyway...last week I adjusted the drum brakes, and it seemed to get worse. So, I marched out and bought and installed new drums. The truck did seem smoother, but there was still a shake. That's when I decided to have the driveshaft checked out, and now here I am.

I'm going to install it shortly and take it for a test drive. It's Thursday again, and super nice out, so hopefully there will be a decent gathering for car night.

Make sure you check the splines on the slip yoke and the driveshaft. If they are worn you can easily get vibrations that come and go depending on if the driveshaft is transmitting power to the rear, to the front, or coasting. I had one that only appeared in coasting and it was the splines.

[Rembrant]

Make sure you check the splines on the slip yoke and the driveshaft. If they are worn you can easily get vibrations that come and go depending on if the driveshaft is transmitting power to the rear, to the front, or coasting. I had one that only appeared in coasting and it was the splines.

Ok, so my newly balanced (and straightened) driveshaft is MUCH smoother! I had kind of gotten used to the driveline vibration and had chalked it up to the engine...it vibrates a little on it's own. So it's much smoother now...surprising really, but I fixed a problem I actually wasn't really trying to fix...lol. It's wonderful, and I'm super happy about it, but I was trying to fix a separate issue.

Still have a little bit of a bounce there somewhere. I think I'm going to replace the 36 year old rotors anyway...there is a bit of a pulsation there at certain speeds.

But Gary, you got my attention with the slip yoke fit. I did check it, and it does seem to have a little slop in it. I have no idea what is normal, but I can wiggle it side to side a little bit. Question: Are the female splines in the slip yoke what wears? Better question is, do the male and female splines both wear, or just the one side, or...?

I might try the other slip yoke and see how it fits, and if it is also bad, I could always order a new yoke.

[Gary Lewis]

Ok, so my newly balanced (and straightened) driveshaft is MUCH smoother! I had kind of gotten used to the driveline vibration and had chalked it up to the engine...it vibrates a little on it's own. So it's much smoother now...surprising really, but I fixed a problem I actually wasn't really trying to fix...lol. It's wonderful, and I'm super happy about it, but I was trying to fix a separate issue.

Still have a little bit of a bounce there somewhere. I think I'm going to replace the 36 year old rotors anyway...there is a bit of a pulsation there at certain speeds.

But Gary, you got my attention with the slip yoke fit. I did check it, and it does seem to have a little slop in it. I have no idea what is normal, but I can wiggle it side to side a little bit. Question: Are the female splines in the slip yoke what wears? Better question is, do the male and female splines both wear, or just the one side, or...?

I might try the other slip yoke and see how it fits, and if it is also bad, I could always order a new yoke.

Glad that helped a bunch. But fixing one layer always uncovers another layer.

On the splines, in my case both sets of splines were badly worn, meaning the slip yoke and the driveshaft. And the key was being able to move the driveshaft side-to-side when it was mounted.

As for the tires, the Subie we have had a set of tires on it that were slightly out of balance, and when the imbalance got in phase on a smooth road it was noticeable, although on a road with some texture it wasn't. Anyway, as things went in phase and out of phase the vibes would come and go.