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Messages - AT8 Cat

2
Drivetrain Tech / Highway speed vibration, worse on deceleration
Quote from: jcassity;463368
shop manual troubleshooting step for either confirming, or determining if the DS is the culpurt.

mark the DS near where the weights are at the 12, 3, 6 & 9 o'clock positions.

install a hose clamp around the ds while positioning the buckle to the 12 o'clock location.

drive car and observe symtom got worse or better.

rotate the hose clamp to the remaining 3 locations.

rotate accordingly as desired the hose clamp to the location that now removes or reduces the vibration.


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Apparently, the shop manual implies that if a remedy is reached, the hose clamp is then tightened down and kept in place, customer work order is completed.

This is easy and you should be able to have this small test wrapped up in one round trip test hit
not all hose clamps are designed equally so you can manipulate the weight felt on the DS by selecting one with a different amount of steel or bolt size to retest just in case you think the first hose clamp may have been too heavyl

I guess I should try this method with a hose clamp before spending a lot of money on a custom made DS as it won't cost a lot other than my time spent.  It's just I've seen so many on this forum say they've done the same 3.73 mod that I have done and they've sent their DS out for balancing and this doesn't fix their vibration problem.  I've probably seen at least a half dozen on this forum who have had no luck balancing the original steel shaft so I guess this put me off spending time and effort and money into trying to fix something that probably isn't fixable.  Doesn't hurt to try though, so I think I'll go through the motions.  :D
3
Drivetrain Tech / Highway speed vibration, worse on deceleration
Quote from: TheFoeYouKnow;463190
You work in a Ford dealership.  Ford dealership service departments are required by warranty to have a tire balancer that measures roadforce.  Measure roadforce.


Good suggestion as that can be overlooked, but we have road force balanced my tires and rims.  Roadforce is well below spec so no problem there.  Thanks!
4
Drivetrain Tech / Highway speed vibration, worse on deceleration
Quote from: Aerocoupe;463177
Some light reading:

http://www.markwilliams.com/driveshafttech.aspx

https://www.driveshaftshop.com/driveshafts-101

http://pstds.com/critical-speed-chart/

Great reading!  Makes a lot more sense having read that.  Thanks for posting!

Looks like I need to start planning for a new DS.  I'm thinking after all the mods I've made to this car (lowering and 3.73's) and also all the new parts and repairs that have been made that the DS has to be the culprit.  It makes total sense.  I'm exceeding critical speed for stock driveshaft with the 3.73's by roughly 20%.  I will be looking for a driveline shop about this to remedy my problem.

Thanks to all for your help and advice.  Hopefully this spring I'll be vibration free!

Cheers!
5
Drivetrain Tech / Highway speed vibration, worse on deceleration
Quote from: Aerocoupe;463088
If you put the trans in neutral with a manual gearbox and you still have the vibration then it isolates it to the rotating assemblies from the output shaft of the trans to the tires.  This includes bushings, bearings, shafts, etc.  With a slushbox I do not know because I have never educated myself on how they work so I don't know if this holds true with putting one of them in neutral.

So the other issue is also something that has been talked about for years over in the Mustang community with regards to 3.73 and steeper gears which is called critical speed.

http://www.foxtbirdcougarforums.com/showthread.php?33113-vibration-thread-aluminum-driveshaft-cures-it!


Just read all 10 pages of this.  :-O

Sounds like getting an aluminum shaft is going to be the next step but.............critical speed??  I've heard of guys getting their factory steel shaft balanced but that still didn't fix the problem.  Do you think the factory steel DS could be balanced differently if the driveline shop knows that you've changed gearing and therefore have affected the "critical speed" of the stock shaft, or is our factory shafts just not meant to turn those speeds?
6
Drivetrain Tech / Speedo gear choices....
I'm running a 23t gear in mine with 3.73's.  Still reads about 4-5 mph too high but that's about as close as we can get with speedo gears.
7
Drivetrain Tech / Highway speed vibration, worse on deceleration
Hmmm, don't think we've checked the tranny bushing.  Problem seems to be coming from the rear end but I guess the sound might be traveling down the driveshaft.  Worth a look.

Still using the stock DS.  DS has been rotated/turned 180* - didn't fix either.

I wouldn't mind spending money to get an aluminum shaft made up if I knew this would fix the problem but I've already spent over $1500 or more getting rear end done, upper adjustable control arms and tranny mount etc.  It's getting expensive with no results.  I'll have to see if that's the path to try next. 

Does anyone recommend a good place to get an aluminum shaft made up in Southern Ontario (KW area preferably)?

Thanks!
9
Drivetrain Tech / Highway speed vibration, worse on deceleration
Hey everyone,

Starting to get depressed with my Kat.  It has a highway speed (65 mph and up) vibration from the rear of the car.  I don't really feel it in the seat but I can hear it pretty good.  If I take foot off of the gas it gets worse.  It's been into the dealership where I work 3 times on this problem with someone who's been with Ford for over 20 years.  First time was bent axle shaft so those have been changed, but did not fix.  Second time we changed the upper control arms to CHE adjustable to correct the pinion angle (car is lowered), did not fix.  Third time we changed the tranny mount as it was collapsed but this did not fix either.  Car has 3.73's and problem seems like it got worse after gear install.  U-joints and all rear axle bearings, shafts, gear set are new (Ford Racing, Moser).  Wheels are balanced.  Driveshaft hasn't been balanced but looks clean and original weight is still there. 

Any ideas?  Help with this is appreciated!
10
Drivetrain Tech / 88 Cougar AOD very slow to kickdown OD to 3rd gear
Got it.  About 2 years ago when I had the upper intake off I followed this video for adjustment.

http://www.youtube.com/watch?v=6L3hNzxdiYw

This guy suggests no slack in end of cable and no pressure on it either.  Seems simple enough, but this video is much different from the procedure in post #2 by thunderjet302.  Do you think the end result will be different between the 2 adjustment procedures?  I'd like to try it but will have to wait until spring when this Kat comes out of hibernation.
11
Drivetrain Tech / 88 Cougar AOD very slow to kickdown OD to 3rd gear
Mine has the updated brass bushing so that's good.  A TV adjustment procedure has been done but the procedure posted by thunderjet302 has a lot more detail than the one I've tried.  Might be worth a shot.  I know it's important that the stopper that's crimped onto the end of the cable doesn't sit up tight against the adjustment block/rail and mine is adjusted to have a bit of a gap between them just like in the illustration that thunderjet302 posted.

Is the throttle valve internal to tranny on these cars?
12
Drivetrain Tech / 88 Cougar AOD very slow to kickdown OD to 3rd gear
Hey Guys,

When cruising at highway speed and I want to pass someone I put my foot down on the gas and about 4-5 seconds later she finally kicks down into 3rd.  Is this normal for these cars to take that long to kickdown?
13
Drivetrain Tech / Shift / linkage problem
Quote from: Gary3072;455975
Were you able to get the old broken piece out ? If so how did you do it ? Also how did you know the correct length of the piece so the shift  fits correctly ?

I used a small piece of 2-sided tape on the upper broken piece and fished it back down with needle nose pliers and grabbed it that way.  Took some time but eventually got it.  If I had to do it again I might have tried one of the "flexible claw pick up tools" which would have worked even better I think and they are usually less than $10.  For length I just laid out all the broken pieces together to figure out the right length.  After I had the right length I rounded the edges and greased them up so they wouldn't damage the contact points especially the shifter  button.
14
Drivetrain Tech / Shift / linkage problem
I replaced my broken "string of beads" by cutting off a piece of an old toy hand held windmill on a plastic stick that my daughter wasn't using any more.  You can probably buy one at Walmart or dollar store.  Just cut the right length, lube it up and slide it in.  The plastic handle on those windmills are tough and very flexible.  Good for going through the s-shaped shifter tube.  3 years later still working mint!
15
Drivetrain Tech / How to correct speedo after changing to 3.73 on '88 Cougar
Wow, sounds like I've got a few options!  You guys are awesome.  Thanks for the good information, I'll have to sort through it all and figure out what's best for me.  7 kph isn't too bad, at least I'm going slower than what speedo says.  I like the idea of swapping over to a t5 but that's probably a few years down the road.  I appreciate the tips!

Cheers!