We were looking at two driveshafts in the garage today and are trying to determine their use. We think maybe one is 55 and the other 56.

Both have the same length shaft, 55 inch center to center with same ends, cast or part #5662636. I assume 98s had a longer c-to-c length shaft, since the wheelbase was longer. The difference is in the yokes that slide into the trans. One is about 5-1/2 center of the u-joint to end that slides in trans, and has a cast # 5666445. The other yoke is 7-5/8 center to end, and has cast #5666687 (5668 on one ear and 687 on the other, plus STEEL and ARMA stamped or cast in). This longer one also has the inside splines starting at least 2 or 3 inches down from the end of the yoke. Any ideas on these? Thanks.

 

From what I understand is that the 98 had a longer tail shaft on the transmission than the 88 did. This might make up for some of the difference in the wheelbase, so maybe they just used the same shaft with different yokes for the different models? Or if one is a 55 and the other a 56, maybe the older hydramatics and the jetaways used different yokes?

 

We were thinking the longer yoke might be for a Jetaway aren't very familiar with them, it would obviously slide further up into the tailpiece and apparently the first couple inches don't do much since no inside splines.

 

I don't know but I would be surprised if there is any difference in the length of the transmission in the 88 and 98. However, I believe the 98 had a longer wheelbase so it seems the driveshaft would be longer. I don't know, I am just guessing.