[Fot] TR4 High speed driveline vibration

[Jim Gray]

I have verified all the driveshaft and trans mount bolts are tight. I use a
J type OD and I haven't been able to find a trans mount for the J type in
this car. I believe they are available for the early tr6 and TR250.
Even though I don't believe yet it's the trans mount I would still look at 
a better trans mount than I currently have. Does anyone know if the trans
mounts were the same from the IRS 4A frame to the TR250 /early TR6 ?
I'm still hoping my driveshaft is either out of phase or simply out of
balance.
jim g

-----Original Message-----
From: rkramer3 at austin.rr.com [mailto:rkramer3 at austin.rr.com] 
Sent: Tuesday, June 16, 2015 6:02 AM
To: toodamnfunky at comcast.net; malaboge at aol.com
Cc: fot at autox.team.net
Subject: Re: [Fot] TR4 High speed driveline vibration

Or just buy one of the ARE poly trans mounts and forgetaboutit.

Bob Kramer
rkramer3 at austin.rr.com

---- malaboge at aol.com wrote: 
>  FOTer's,
> I will assume this car has the stock style trans mount, not the later TR6
style setup...yeah I know about assuming anything, but here I go.
> In order to keep the rear of the trans where it belongs and yet allow some
movement and inslulation this is the mod I have utilized.
> Remove the 2 trans to mount bolts and drill straight down thru those
mounting holes thru the small trans crossmember. Enlarge those new holes in
that crossmember to about 5/8" or so. Purchase 2 new bolts that are treaded
all the way and are long enough to go thru the trans, the trans mount and
the crossmember. Drop the bolt thru the trans and trans mount and start a
nut up the bolt to tighten the trans to the mount. The bolt will now extend
thru the trans, the mount (tighten the nut securely to hold them together)
and the crossmember. Use a large washer and a nyloc on the bolt where it now
extends thru the crossmember. Tighten this nylock only until it "just"
contacts the crossmember. Because the bolt is smaller than the hole you just
drilled it will allow the trans to move a small distance in any direction,
but will stop any excessive movement, including saving the radiator in event
of a serious impact!
> 
> Clear as mud?
> 
> A little out of balance in Nor Cal
> Nick
> 
>  
> 
> 
> 
> -----Original Message-----
> From: Duncan Charlton <duncan.charlton54 at gmail.com>
> To: toodamnfunky <toodamnfunky at comcast.net>
> Cc: fot <fot at autox.team.net>
> Sent: Mon, Jun 15, 2015 12:23 pm
> Subject: Re: [Fot] TR4 High speed driveline vibration
> 
>   Jim,
> How are your motor and trans mounts?  If they allow the engine/gearbox
combo to shift out of line when under high torque, the u-joints could move
out of proper alignment, but then when power is reduced, things would shift
back into position.  If you put the car on jackstands and run it to this rpm
in top gear (might not be a bad idea to remove the drive wheels and tires if
you’re sure they’re balanced) there won’t be much load on the engine, so if
the vibration is due to deformation of the mounts, the vibration should not
appear.
> Duncan
> 
> On Jun 15, 2015, at 10:55 AM, toodamnfunky at comcast.net wrote:
> FoT,
>  I have a driveline vibration that doesn't start up until I get to about
95- 100 MPH. I figured I would start with the driveshaft
>  before looking into the diff or OD/trans. I have an IRS car with Richard
Good CV axles and hubs so it's very un likely its that but
>  I will inspect them. I'm wondering if anybody has any advice on high
speed vibration diagnosis or detection.
>  What I'm wondering is even if it is the driveshaft how would I know with
it sitting on my bench. 
>  Any help would, as always be greatly appreciated.
>  Jim g
> 
> 
> _______________________________________________
> 
> 
> 
> 
> 
> 
> 
>  
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