problems with IRS diff fit...

[wibby]

Anyone else have problems getting the IRS differential into position in the frame. The yolk on the diff hits the frame before the diff cover clears the lower control arm frame mount tabs. I need another 1/2" before it will clear the tabs. The diff is shoved as far forward as it will go. Anyone else have this problem? I think the diff will go in if I remove the diff cover and re-install it with the diff in place.

Wibby

[AJT '33]

Your not the first one to have this issue, here is a link to another conversation: https://thefactoryfiveforum.com/showthread.php?27773-33-with-8-8-IRS-doesn-t-look-right-to-me-how-about-some-of-you-guys-with-the-same&highlight=differential or https://thefactoryfiveforum.com/showthread.php?26821-JimLev-s-Build&p=316079#post316079 it has a good string of "how to". I would highly suggest that your patient, move it on place and it will fit in. Have a look and f there are further questions, please go ahead and ask, its a tight fit!
89020 89021

[wibby]

Thanks AJT, but the problem I'm have is different than those posts. They had problems with the bushings being off. I have that problem too as I measured the mounts on the diff and the hole spacings on the frame, but I fixed that with offset bushings. The problem I'm having now is that the diff won't go far enough forward to clear the rear pair of lower control arm mount tabs that are welded on the frame. The yolk hits the frame before the rear diff cover will clear.

[JimLev]

It was a bear getting it to fit in, but it should fit. I didn't need to remove the rear cover.
All the frames are jig welded so they should all be the same.
IIRC (it was 4+ months ago) I rotated the diff maybe 20 deg, pushed it up and then in.
I may have had some of the bushings out for more clearance, then put them back in before I aligned the mounting holes with the frame.
I don't have the body on yet so if you need any measurements let me know.

Also, is this a new diff from FFR or from a donor car? Mine was from FFR.

[AJT '33]

Thanks AJT, but the problem I'm have is different than those posts. They had problems with the bushings being off. I have that problem too as I measured the mounts on the diff and the hole spacings on the frame, but I fixed that with offset bushings. The problem I'm having now is that the diff won't go far enough forward to clear the rear pair of lower control arm mount tabs that are welded on the frame. The yolk hits the frame before the rear diff cover will clear.

Possibly get a picture to help us help you. If you notice in the second picture we pulled the nuts off and the bolts back to allow it to get by.

[wibby]

It is a new IRS from FFR.

[progmgr1]

It's been a few months, but I do remember it being a moderately difficult job. However, I was able to install the diff myself by using an engine hoist with a lifting strap to pull the diff up from below. That way I could lift and tilt the diff at the same time - one hand on the lift handle and the other guiding the nose into the chassis. It took a few tries to get the technique down, but the diff went in with all the bushings in place and no eccentric holes or tapers. I did have to spread the tabs a little, but that was it.
Keith

[1932]

Pics on post 21 in toms 33 build

[q4stix]

I think I tried going with the yoke facing up while lifting and eventually went with the yoke facing down, lifted the diff above all the mounts, and then lowered it back down.

[AJT '33]

It is a new IRS from FFR.

Mine was a new one from FFR as well (I just painted it up nice and pretty!) it took my son from the top and me from the bottom with the floor jack to get it in, we took about an hour to slowly wiggle it into place. Be patient and try various ways, it will fit.

[wibby]

Thanks, I have not tried the yolk down approach. I will try that this weekend.

[Packer fan]

I also have the ffv IRS.
I believe it took a pretty good angle, front up.
Lift it through and slightly above.
Then lowered it in place.
It took 2 of us and a floor jack.

[JimLev]

I had the yoke up too when I put it in. Get another set of hands and a floor jack.
I did it by myself, PITA job, but finally got it in.

[UnhipPopano]

If it is difficult to get the IRS installed early in the build, What do you do when the car is completed and it needs to be replaced?

[TxMike64]

If it is difficult to get the IRS installed early in the build, What do you do when the car is completed and it needs to be replaced?

If prepped correctly it shouldn't ever need to come out. The 8.8 can hold a lot of power - the weak link may be the CV axles. But for as little as these cars weigh, there shouldn't ever be a problem.

[wibby]

That assembled IRS differential would not fit in my 33 frame, period. Not front up, front down, rear up, rear down, upside down, or back in time. I will say though, if you pop the diff cover off, it goes in with no problems (well excluding the offset bushing problem). Also, there is plenty of room to reinstall the cover and not even mess up the RTV, which I applied to the cast iron portion that was installed in the car. So, if anyone is interested in an easier approach to installing the IRS rear diff, just pop the diff cover off.

Wibby

[AJT '33]

That assembled IRS differential would not fit in my 33 frame, period. Not front up, front down, rear up, rear down, upside down, or back in time. I will say though, if you pop the diff cover off, it goes in with no problems (well excluding the offset bushing problem). Also, there is plenty of room to reinstall the cover and not even mess up the RTV, which I applied to the cast iron portion that was installed in the car. So, if anyone is interested in an easier approach to installing the IRS rear diff, just pop the diff cover off.

Wibby

Hey Wibby, that does suck, I would take pictures and send it to Tony Zullo and the team as you should not have to do that, it does seem something in the jig is not correct.

[JimLev]

Wibby, good to hear you got in installed, but like AJT said you should call Tony and see what he has to say.
Keep us posted.