phutch11

Sorry for the bad news about having tried all the "easy" tricks with no success.

Kalli - That's what Gun and I are experiencing, your just getting less of it. If you don't mind checking, what is the total length of your slip yoke?

I'm guessing that a 3" aluminum DS will "fix" the problem by pushing the harmonic from 4200 rpm to higher speeds that are rarely encountered - but it isn't fixing the problems, just the symptoms.

That's not to say I won't buy one, I am getting very tired of replacing everything in my car to try and fix this issue.

What brand of gears are you guys running? I'm running 3.55 Richmonds.

Just trying to figure out the common link...

kalli

3.5:1 ford racing.
can't remember what u-joint but I think it's a 1260-1310 conversion (1" cup dia driveshaft side, 1-1/16" yoke side). not 100% sure. forgotten. b ut as said I still have angles all wrong. so i'll report back on that

Gun Jam

3:80s from summit racing....forgot who makes them

Kalli's vibration sounds like its on the other end of the DS...Im pretty sure mine is at the tail shaft.

-Gun

kalli

if yours is at tailshaft, then maybe it's just the fact of DS being too short ?

Gun Jam

Yes Kalli maybe...ill have to begin perusing that again..the Ron Morris mounts seem like they are going to be okay....maybe im just getting battle hardened but they seem to be softening up a bit... I gotta figure out something with that c4 trans mount.

-Gun

Gun Jam

New Ideas

I talked with Bruce of modern driveline. He said these vibrations are not typical.

His first thought was the 1.7" of slip yoke hanging out of the trans was excessive

His second thought was the slip yoke was worn...

He said if you could get under the car and add force to the DS there should be no noticeable play at the slip yoke and trans...This is not my case I do indeed notice movement at the slip yoke/ trans area.... I also know that If I took dial calipers to the inside end of the slip yoke and the part that rides on the bushing I would find a very measurable difference. .005 minimum probably closer to .010 (maybe ill get real numbers here in a few hours just for fun)

So

1) Find old school style slip yoke and replace old one and see if that makes it okay
2) new drive shaft with 1310 u-joints and correct length and stop pissing about with the one I have now.

If I wanted to find a slip yoke that will fit the original DS where would I get one....

Thanks

-Gun

Gun Jam

untouched section of the DS is 1.502" Section where the bushing rides on is 1.497"

the untouched section requires considerably more effort to slide into the bushing than the last 1/3 of the yoke.

-Gun

kalli

good idea talking to the man how should know.
a yoke sticking out too far will cause wear and vibration alright. that's at least waht the fella told me who rebuild my box. i never had to cut mine. I just couldn't find a u-joint to convert from the mini 6cylinder DS to 1310. So I just bought a used DS from a 66 auto on ebay. To be honest I can't even remember if I left the yoke in there or put the new slipyoke on. I guess I used the new yoke. I'll get more info tonight I hope. maybe even find time to shim it

Gun Jam

Kalli / Scott

Or anybody for that matter

If you guys get under your car and push up on the DS a few times with light to moderate force do you see the slip yoke flex up and down in the tailshaft?

Bruce said you shouldn't see any flex at all I see a clearly noticeable amount of flex and it takes not much effort. I can still see flex when I slide the DS all the way in... Would a new slip yoke really make that much difference?

-Gun

chris66dad

I installed mine a few weeks ago and it was a snug fit and did not move up or down.
I decided to not have my original DS shortened and instead bought a Coleman Aluminum DS from Street or Track for 299 and it came with 1310 Ujoints but no slip yoke.
My total freeplay is 7/8 of an inch. There is not any vibration up to 65 mph. Still sorting out alignment problems so I did not go faster than that.
Hope you find the problem soon