help with IRS Installation #7967

[cobratech]

Getting ready to install the irs differential and having some difficulty with the diff to fit up between the frame. The instructions say it "installs from the bottom with the driveshaft flange pointing straight up and the axle holes lined up front to back with the chassis". Have made a couple of attempts to get the diff to fit but don't want to cause any scratches to the frame or diff so are trying to be extra careful any suggestions or photos would be appreciated . thanks

[Mesa Mike]

It's been a few years since I installed mine but here is how I did it. First, it was early in the build with no alumn. installed yet. I had my wife lay on the floor as I stood over the IRS frame. As I recall I lowered it in from the top with the driveshaft flange pointing up. I rotated the diff as I lowered it into the frame as my wife took some of the weight off by "bench pressing" the diff as I rotated the axle holes clockwise. It was actually very easy. Good luck.

[hrosenthal]

It took me a few hours to get the pumpkin into place. You need to follow the instructions to the T. There is no room for any deviation. It's kind of a lift and twist motion. The weight only complicates matters. I wish I had photos, but I did it alone (which was a mistake for several reasons), with nobody around to take the photos. If you are not able to lift and maneuver the 80 lbs into place, find someone to do the heavy lifting from underneath while you direct from above. I don't see any way two people can share the lifting. Also, keep in mind that your powder coating may take a bit of a beating. Some high gloss rustoleum will fix that up. This job is the poster child for persistence. Good luck.

[hrosenthal]

As I recall I lowered it in from the top with the driveshaft flange pointing up.
Mike - What model do you have? I don't think it's possible to get it in from the top on the MKIV.

[carlewms]

I just finished the installation on a Mk 4. Here are my lessons learned:

1. The fit of the differential is very tight as you move it up through the IRS cage. Between my addition of a couple of layers of paint on the differential and powder coating on the frame it was too tight a fit and I had to trim a little off to get it to fit;
2. Make sure to remove the plastic plugs in the differential axle connections;
3. Two persons can do it but three would be better; two steady the differential from the sides and one to operate the jack;
4. I used a rolling jack to support the weight of the differential; I kept it steady and my friend maneuvered the jack;
5. The diff must go straight up as described in the manual; any deviation and it won't make it through;
6. I ended up using some line thru the forward mounting points to steady the differential;
7. Make sure that when you twist the differential in position, you take advantage of the semi circular cutout in the forward cross frame of the IRS cage;

Carl

[GWL]

Try this link to a thread I posted with pictures:

http://www.ffcars.com/forums/17-factory-five-roadsters/245886-installation-irs-center-section-how.html

George

[Mesa Mike]

cobratec......MKI. It had full IRS cage from the factory and I used a '91 Thunderbird super coupe. Fit like a glove and I love the performance. Changed the 3:27 to 3:55 and it really performed so much better in town at low RPM.

[cobratech]

Thanks for all the great replies very tight fit but once you get the diff in the correct position it goes right were it belongs. thanks again!!

[teesalmon]

I would like to make one comment. On my Mk4, and maybe others, the pumpkin would only install if I had nose up, half shaft openings lined up from to rear of the car,

AND the bottom of the pumping facing the passenger side of the car.

I did not have to remove the rear cover. I measured the mounts for the rear cover before I started, it was tight, but did not require any force or bending. I first tried it with the bottom facing the driver's side and it would not install.I was going to take the rear cover off, but when I looked at the situation again, the rear cover was not my issue. It was still a tight fit, and required a little nudging. Watch your fingers! I made a small wood fixture to help keep it on the jack on the way up.

[CraigS]

1.5 yrs ago I helped Bill3422 install his. I was dreading it but it was much easier than I expected. Due to the tight fit and the weight I think you just plan on doing some touchup afterward. I see no way to avoid that. It's just too ungainly. And my fingers are too important.