North American Turbocoupe Organization



Duh! Driveshaft!
vegas_ss Offline
Senior Member
#1
A while ago while driving on the interstate around 70ish, there was a pretty noticeable driveline vibration going on when all of a sudden I heard a noise and things smoothed out.  Been driving fine and forgot all about it.  Today when changing the oil I was looking around and noticed what had happened was the driveshaft balancing ring had come apart and the outer ring was up around the transmission tailshaft.  Luckily it stayed put or who knows what may have happened.  I'm just going to remove it for now.

I did have another 87 turbo coupe and had the driveshaft rebuilt and balanced however they removed the balancer since they weren't able to balance the driveshaft with it on.  I did have problems with that setup, mostly noticeable during slow speed driving in 4th gear, not really lugging the motor, but at low rpms it would cause quite a bit of vibration.  I assumed at the time that the balancer/dampner really did it's job.  Now that I'm missing the outer ring I wonder since I don't really have those same issues.

What is the consensus on the driveshaft balancer?  Is there a replacement available or can it be rebuilt?
1987 TC, 5sp, Boport Stage 3 Head/2.1 Cam
1996 Impala SS
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Jeff K Offline
Administrator
#2
I am sure Ford engineers put it there for a reason. They probably could have saved $5 per car = several hundred thousand $$ over the years the TC was built. My guess its purpose is to absorb torsional vibrations in the driveshaft caused by excessive crankshaft acceleration / deceleration inherent in a fairly large displacement 4 cylinder engine. My 86 Tbird 5.0 doesnt have the damper ring as crank acceleration / deceleration is much less with a V8 engine. Again just a guess on my part based on info I gleaned from working with a few mechanical engineers on various projects during my carrier.

No clue if replacements are available or not, but I doubt it. Since the rubber in the damper is firmly attached to both the ring and the driveshaft, I doubt it can be rebuilt, but it might be worth asking a driveline shop about it.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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vegas_ss Offline
Senior Member
#3
I made an appointment at a local driveline shop however the first available wasn't until July 17th. When I removed the driveshaft to slide the yoke off I found the rubber boot at the trans tailshaft ripped up pretty well. Looks to be more of a dust boot than a seal though. I'll have the driveline shop check it out.
1987 TC, 5sp, Boport Stage 3 Head/2.1 Cam
1996 Impala SS
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Jeff K Offline
Administrator
#4
The seal / dust boot at the back end of the tranny is cheap an easy to replace.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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vegas_ss Offline
Senior Member
#5
I did order the seal/dust boot from Rockauto, not sure if I will try and replace it or wait until I take it in.

Was thinking that it seems to drive fine without the outer balancing ring so there may not really be a need to replace the slip yoke. I was looking around online for one, but of course I didn't measure it and not exactly sure on the length. I do see some listed as for an AOD or T5 but other comments that the slip yoke is different between the AOD and T5.

I also was looking around to see if there are places that can rebuild the slip yoke balancer assemby. I found some places that do harmonic balancer rebuilding and thought it may be the same process?

Would need to get the correct slip yoke in order to remove the stock unit to have rebuilt so any help in figuring out what the correct slip yoke for a 1987 TC with a T5 is appreciated.
1987 TC, 5sp, Boport Stage 3 Head/2.1 Cam
1996 Impala SS
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anasazi4st Offline
Senior Member
#6
(06-27-2020, 03:49 AM)vegas_ss Wrote: I did order the seal/dust boot from Rockauto, not sure if I will try and replace it or wait until I take it in. 

Was thinking that it seems to drive fine without the outer balancing ring so there may not really be a need to replace the slip yoke.  I was looking around online for one, but of course I didn't measure it and not exactly sure on the length.  I do see some listed as for an AOD or T5 but other comments that the slip yoke is different between the AOD and T5. 

I also was looking around to see if there are places that can rebuild the slip yoke balancer assemby.  I found some places that do harmonic balancer rebuilding and thought it may be the same process?

Would need to get the correct slip yoke in order to remove the stock unit to have rebuilt so any help in figuring out what the correct slip yoke for a 1987 TC with a T5 is appreciated.

My harmonic balancer also fell apart, in 2014. I removed it, and have had no issues without it. It seems like it does nothing, but as Jeff said (and I concur) Ford put it there for a reason. However, without it seems fine as well.

I CAUTION YOU: this might seem obvious, but that depends I guess on your perspective. If you mess with the front slip yoke and snap rings, BE CERTAIN to use a brass mallet to tap on the yoke and MAKE SURE they are seated properly. I thought I had done this, but several miles later going onto the freeway—the driveshaft came loose from the T5OD transmission.

I am not making this up.

It was a horrible experience. The car was put on a flatbed and brought home. I ended up with a new driveshaft—the OEM one got all dented up. The problem is—it was still connected to the wheels, so it banged around under the car (I still have dents on the floor pan). Fortunately most damage was avoided—but I do believe that the two sheared off mounting ears on the block for the bellhousing, and the broken ones ON the bellhousing—were a direct result of the torque from that experience.

Had I used a brass mallet, that likely would not have happened. I did not want to bang away too hard on the yoke with a steel hammer, because of the resulting dents and unbalanced condition. A BRASS mallet would not have caused that, and would have better seated the snap rings. I therefore also should have better verified that they were in place.

It is my single greatest regret in the ownership of my TC.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 1 T5OD full rebuild, 5 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
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vegas_ss Offline
Senior Member
#7
Wow, I'll be sure to double check them!
1987 TC, 5sp, Boport Stage 3 Head/2.1 Cam
1996 Impala SS
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