Gun Jam

This whole thing was kind of annoying but now its just downright funny.

I called Denny's DS he said he also thought it was a balance issue but maybe DS was reaching critical speed or it could be a pinion angle. He said pinion angle isn't super critical it could be off a deg or 2 and still be fine he said both the engine AND pinion should be at -3 deg....but having it get worse when you back off the gas sounds like it could be an angle issue.

SO

I call this shop Alltech Auto and they said "its probably balance" we would just take the DS and have bayshore truck balance it first. I was like well okay...They then asked who balanced it the first time and I said Mcallister automotive some guy named Buddy. They said "well that sounds sketcy just talk to Bayshore truck and have them balance it"

SO

I call Bayshore truck and tell them my story..they said "well who balanced it last?....OH Buddy? I know him!!! he does great work he used to buy stuff from us...I bet its an angle problem" im like

SO

its obviously a vicious cycle that won't end I'm just going to go to Bayshore and have them check the angle because they thought it was a good idea and belive that Buddy did a good job on balancing the DS and all roads end at bayshore based on the conversation with AllTech auto.... BayShore can balance and check angle.... with a fair price.

Final note...Denny's DS said to check and make sure the bearing caps on the rearend side of the DS were 1" and not 1 1/16" or that would cause a big problem on the ford 8"....I cant guarentee they were 1" maybe they got mixed up they were installed..or the wrong ones were picked out, or the wrong ones ended up in the right box..... Im going to check this straigt away!

-Gun

snorulz

at least you only have to work with one place now. Best of luck to you!

Norm Peterson

Before = old tranny = OK.
After = T5 = vibration.
Obviously something changed.

How much vertical distance is there in your T5 between the centerline of the output shaft and the face of the mounting pad? How does that dimension compare to that of your previous tranny, and did you do anything to accommodate any difference?

If the tranny output shaft is indeed "high" now compared to before, a pinion angle that was OK before could easily be too much "down" now.

Just out of curiosity, did you also change the amount of weight in the trunk and/or back seat at the same time? That'll change pinion angle too.


Norm

urban_cowboy

As Calvin Coolidge said, "Nothing in the world can take the place of persistence...The slogan press on has solved and always will solve the problems of the human race."

Good luck. I bet you are close.

Gun Jam

Norm

I dont know how the distance now compares to the C4. No trunk weight was changed. I'll let you guys know what happens here when I check bearing cap size and maybe after a visit to bayshore truck....

Again thanks for your help

-Gun

kalli

Hi Gun, you know I have the same problem. I spent the whole weekend putting my engine back together. it seems to drive now so I'm a happy camper. will take it for a spin midweek and let you know if the change to 5leaf made a difference or not. If it did, then my problem was the angle (no matter if it changes to better or worse).

As towards the 1" and 1-1/16. i no way I want to doubt on what denny say as they are specialists for ds and joints. but I can't see how 1" or 1-1/16" makes a difference as long as you have the correct joint for the shaft and pinion. 1" caps on a shaft are 1260 style joints where as the 1310 style are 1-1/16"

my rear axle pinion is 1310 style with 1-1/16" and my driveshaft end is 1260 style so I had to get a conversion U-joint. I am currently not concerned about that as the outside diameter of both styles are the same. But who knows, maybe that's exactly what gives me/us the problem.

as said if in my testdrive the issue still persists I'll probably buy a new shaft ...
But yes. persistance helps. And just as norm said: my problem only appeared as I changed over to T5
But I changed the driveshaft at the exact same time as well as rear axle. as I couldn't get a conversion for the old shaft. the new one (DS) I have I bought used of eBay (from a 1966 289 auto) and that thing has seen better days.
Rotating speed stayed the same before/after the swap as the rear end ratio stayed at 3.5:1

I have it down to:
DS length or
DS balance or
pinion angle.

nothing left anymore. I hope we'll get to the bottom of it soon. I'm afraid to destry the T5 with all those vibrations so I'm driving very carefully (slow) ... :-(

Gun Jam

Well I would think trying to stick a 1 1/16th cap in the rear end receiver (which is machined for a 1" cap would cause a poor fit and improper alignment.

Good luck to the both of us right...

-Gun

kalli

if it's machined for 1" you won't even fit a 1-1/16" in there. it's only minimal but should never work. ... and sooner or later we'll have it. you have plans, I have plans. one of us has to succeed ;-)
what I meant with my driveshaft and seen better days is that I have the joints in but it's not very very tight. I have a little tiny play. If I bomb it with the grease gun it is tight, but only for about 2 mins driving then I can feel that play again. it's minimal but who knows. at this stage I'm ruling nothing out anymore.
What adds to it is that I tried to balance it with driving on pit and chalkmarks. I attached selfmade weights to it, but if I add a bit of weight the chalkmarks seem to jump. and even when I get it right so that the chalkline seems to be going nearly the whole way round I feel it vibrating,. I just don't trust any of this anymore ...

kalli

on a sidenote. I see from your other post that you have a lot of knowledge about the T5 conversion from an auto. did you do that to yours? if yes then we might just have the exact same driveshaft as I mentioned i got mine from a 289 66 auto. did you shorten that thing? do you have a 8" rear or 9"? according to the fella i got the 9" from he said no driveshaft modifications. Therefore we should both need the same length. I haven't cut mine.
Maybe our shafts are just a tad to short causing vibrations?! do you have a dust cap (a rubber boot) on the end of your T5? can you re-upload the picture where it shows the shaft coming out of the T5 that you had?

Gun Jam

my DS was from a 66 auto. its 1" shorter than stock at stock play was nearly 0 now its got nearly 0 + 1" of play for bumps see photos. If you need your DS shortened or not seems to have a lot more to do with luck than with logic, year, rear end, transmission, car color or engine size. I did all the T5 swap myself other than the DS

It better not be a tad short i already have way more invested in that DS than its worth.





Humm the angle of the trans looks about right from here

-Gun