View Full Version : Mk 4 Roadster transmission mount question
Good day all
Im presently installing the transmission support A frame with the attached flexible mount. When I lower the TKO 600 transmission on the jack, it contacts the lower cross member. When I jack the transmission back up such that the drive shaft is aligned with the IRS input flange, there is an approximate 1 inch gap between the A frame and the threaded lower attachment of the flex mount. The engine flex mounts for the Dart 351W / 427 are installed correctly so the engine is not sitting too high. Any Ideas? Thanks
FLPBFoot
02-04-2020, 07:03 PM
Yes you will need spacers and longer bolts to engage the transmission mount. I think mine was about 1 1/4 in spacer. I used 1/4 inch AL flats stock and cut and drilled to fill the gap and align with the input flange.
Be sure you are doing this with the weight on the tires as the suspension sag will change the angles.
Yes shim between the mount and the A frame. You mentioned IRS so suspension sag won’t change anything. What is important is matching up the angle of the drivetrain to the angle of the pinion flange on the diff so the driveshaft U joints are in phase. Dozens of threads on this if you need to read up.
Final shim height will be determined when you get the correct angle.
Yes shim between the mount and the A frame. You mentioned IRS so suspension sag won’t change anything. What is important is matching up the angle of the drivetrain to the angle of the pinion flange on the diff so the driveshaft U joints are in phase. Dozens of threads on this if you need to read up.
Final shim height will be determined when you get the correct angle.
Thanks so much for the information
Thanks for the assistance
chuckster
02-05-2020, 07:33 AM
Mike Forte sells shims for this.
rich grsc
02-05-2020, 10:06 AM
So does any hardware store, just use washers, you can get the exact fit you need.
GoDadGo
02-05-2020, 11:00 AM
Remember To Phase Your Driveline!
https://youtu.be/Idk3BVDVHq4
Bad Things Happen If You Don't!
rich grsc
02-05-2020, 11:47 AM
Remember To Phase Your Driveline!
https://youtu.be/Idk3BVDVHq4
Bad Things Happen If You Don't!
Don't confuse 'phasing' with u-joint angle, two different things. Phasing is done when the driveshaft is made and the yokes are welded to the shaft. It is not possible to get the shaft out of phase, as you can't move the welded yokes. The angle of the u-joints are the only variable we have to contend with. They need to be as close to parallel as possible.
GoDadGo
02-05-2020, 12:57 PM
Don't confuse 'phasing' with u-joint angle, two different things. Phasing is done when the driveshaft is made and the yokes are welded to the shaft. It is not possible to get the shaft out of phase, as you can't move the welded yokes. The angle of the u-joints are the only variable we have to contend with. They need to be as close to parallel as possible.
My mistake!
Thanks for correcting!
I didn't sleep at a Holiday Inn Express last night.
Just double check the angle of the driveshaft dangle right & vibrations won't be an issue!