gear swap

[amc1989]

I have an 81 SX4 that I believe has a 2.73 ratio. Would I be able to put a 3.54 gear set in this? I would like to be able to use a locked Chrysler 8.25 from my old Cherokee and this would be easier than finding a front diff out of a 4 cly SX4.

Thanks

[txjeeptx]

I recall that there is no way to get 3.54 gears, new from the aftermarket, or factory originals from another Eagle, to work with the differential case(what the ring gear is bolted to) from anything else but a 3.54 axle. The ring gear mounting surface on the differential case of any other ratio(like 2.73, 3.07, 2.35, etc) does not have the right offset to mesh the 3.54 gears correctly. The Eagle uses a D30 low pinion gear set, which is shared with the early 80's Jeep CJ D30, so there are aftermarket gears available, but I recall you need the 3.54  differential case to get the gears to set up correctly.

Its been so long since I went through the front gear swap problems that I don't recall what the final answer was on it. I know I had a 4cyl front axle shipped from Massachusetts to Texas, and when it arrived, it was so beat up that neither of the axle shafts were useable(flanges bent), and there was a bolt broken off in the top of the housing, so I think I swapped the gears, shims, and diff case into my original 2.35 housing and just replaced all the bearings, and reused my original axle shafts.

You might be able to use car-part.com to locate a 4-cyl Eagle anywhere you can, then call them up and have them send you the differential carrier and gears, along with all the shims, rather than getting the whole housing shipped.

[amc1989]

Would 3.07 ne possible, if it doesn't already have them? Cause I can get a 3.07 Cherokee diff easy and put the locker in that. I have an 81 with permanent 4wd so from the research I've done I either have 2.73 or 3.07. Haven't had much time to work on it cause of school so I haven't had a chance to check which.

[txjeeptx]

. . . and if I could actually recall what I had done in the case of my axle regear. I got a spare axle housing from TrapperJack, and it was a non-disconnect 3.07 housing. I know I didn't use that housing, because its buried in the corner of the shop somewhere. I recall having tried to fit the 3.54 gears onto the 3.07 diff case and not having any luck getting the gears to mesh up properly. I think we(the differential shop and I ) used my 2.35 housing with the 3.54 gears and 3.54 diff case, since the housing they were shipped from Mass in was no good(messed up axle mount bolt hole). It was several years ago, and for what its worth, I should spin a tire over and count the driveshaft revolutions to check if they actually installed the ratio they said they did. It was one of the most perplexing things they'd ever come across, trying to regear an Eagle front axle. There has to be something different in there, becuase I have the original 2.35 gears from my housing, but for some strange reason, I also have a set of 3.54 gears with a beat up pinion(bad threads), and mysteriously no 3.07 gears, and I know the buried-in-the-shop 3.07 non-disco housing is empty. I wonder if they stuck the 3.07s in there, or if we managed to use new 3.54 gears from the low pinion CJ D30 application. Its all too long ago to remember. Before I get the car back under its own power(going on two years down), I'd better check it out.

[eaglefreek]

  Its all too long ago to remember. 

http://forums.amceaglenest.com/index.php?topic=21608.0

I suffer from CRS also.  Here's a thread that discuss the 3.54/3.55 ratio issue.

This was in a reply from a member in that thread. I can't say that it clarifies anything though.

[amc1989]

Thanks for the info. It sounds like 3.54s will fit since I have an 81. If I already have 3.07s in it I'll probably leave them and get a Cherokee rear end. If not I think I'll try the 3.54s 

[txjeeptx]

Good info. Guess thats why the 3.54 gears fit into my stock 2.35 housing, since its an 82, before something was changed in the housing design.

[carnuck]

The change was for the vacuum shift setup and the hanger changed on the housing. 2.72 was more common than 2.35