1772 rear change out

[Oak]

I'm starting a shopping list for installing a CI rear in my 1772. Will any CI wide frame hydro rear work? The hydro pump was removed and rebuilt by the PO and I hope it's not messed up. The tractor is slow in forward and reverse but it may be a linkage problem or a fluid problem. The coupler at the hydro has slop in it and I'm not sure if it's the shaft or the coupler. What is my best option for a drive shaft and do I need to keep the drive shaft disconnect clutch?

[Matt G.]

The driveshaft itself is probably fine; it's most likely the coupler on the trans. The input shaft is hardened and the coupler is a rather soft type of cast iron. Replace that and it should be good to go.

Any external brake hydro rear CASE will work. I did this exact swap in my 1872, and I used a 127 rear. I'd recommend you read through the 1872 page on my website, as it shows the whole process I went through.

The only 'catch' here is you'll have to do a lot of mixing and matching of parts inside to get this to work. The supers have a different reduction ratio than the GTs do, so you will have to put the driven reduction gear from the aluminum rear into the CI rear. TO do this, you have to completely disassemble both rears, so at that point, the best thing to do would be to put all of the guts from the aluminum case into the CI case, giving you the much stronger fine-spline axles and carrier and the stronger, heavier CI case: the best of both worlds.

This is not a very simple project, and doing mine was one of the most labor-intensive things I have done, but at the same time, I learned a lot, and it was a very rewarding experience. It took me 6 weeks to get my 1872 fixed up, with most of that time being the rearend swap. That's the same amount of time it took me to put the loader on my 682. You need to get both the CCC service manual and any IH service manual and start studying the rearend sections in both. There is one error in the IH manual-- the direction for shimming the carrier left or right to get the appropriate contact pattern is bassackwards. The worst part is probably setting the pinion depth and carrier and getting the right contact pattern and backlash. I can talk you through that if you like. I also had to file away some casting flash in the case because the super driven gear is thicker.

Option two would be to find either another super aluminum rear (good luck finding one that isn't broken) or an iron rear out of a 982. However, the IH-built 982s had coarse-spline axles, which will twist off in a super under heavy load. Both of those will also be really expensive if you find one. It took me 6 weeks to do mine, but I don't have much money in it, and most of that time was spent trying to figure out what the heck I was doing, as I was basically in uncharted territory. Few forum members have been there. I could probably do this again in half the time, now that I know what I'm doing.

[midyearguru]

Are there any inherent problems using a CI case from a Quietline series with internal brakes?

[Matt G.]

You'll have to deal with the internal brakes...If I were using an internal brake rear, I would leave that intact, and hook up the left side pedal to that as a parking brake, and then keep the brake discs when you swap in the fine-spline stuff from the aluminum rear to keep the turning brakes, too.

One problem I can see is that the super's reduction gear is thicker, and there may not be room in the case for the brake pucks with the thicker gear.

[midyearguru]

Interesting idea. I was planning to just strip the CI case and start from there.

[Oak]

I'm gonna give it a try as soon as I get my 126 back together after 10 months of being in pieces.