What is my gear ratio in 1982 SX4 2.5l iron duke, T5

[Monkeyjoe]

I know I asked this question before, but the eaglesnest is down and that whole thread is gone from this forum.

I have a 1982 SX4, with the 2.5l Iron Duke, and the T5 5spd.  I could go into the whole story but now just need to replace a set of gears in the rearend. 

The wrecking yard put the wrong axle in the car as some of you may remember that whole story.  I will be returning home from my deployment in a couple of months and I am ready to order the gears and installation kit. 

I cant remember what gears you all said would be in my car.  Was it 3.55 or 3.72.  If memory serves me correct I think someone on here said it is the 3.55.

Also, does it matter if the gears are for a dana or an amc rear end? will they fit in both?

[IowaEagle]

4 cylinder with a T5:    Low altitude cars:  2.73;   High altitude models & California cars:  3.54   AMC/Dana cases are the same.

[Monkeyjoe]

the car is a Wyoming car elevation around 7000 feet.  I think that counts as high elevation.

[IowaEagle]

If it was first sold in a high elevation area then it could have been.   Look to see what is stamped just to the right of the diff cover.  "J" = 2.73 and "E" = 3.54.

[Monkeyjoe]

thanks, I will have to wait till I get home before I order the parts then.  The wife cant crawl under the car to look.  So I will have to when I get back.

Thanks for the info.  Now if it doesn't get lost before I get home I will refer back to this post.

[IowaEagle]

I don't think it will be lost anytime soon.  Unless I break something here.

[Monkeyjoe]

Just glad to see some of the familiar "faces" here.  I have missed being able to talk about Eagles.  It had been one of my favorite stress relievers here.  Now I found the new forum, I am looking forward to catching up.

[IowaEagle]

....... much less stress for me as well.  We have a great team here.

[carnuck]

Didn't 4.10 and 3.73 come as an option for the 4 cyl 5 speed?

[IowaEagle]

I was thinking the same.  I went by what the '82 TSM said.   So, I checked some other year's manuals.  In '81 according to the TSM, 151, 4 speed cars only came with 3.54's, '83 TSM says that 151's came with 3.54 gearing across the board.; and '84 onwards, the same, 3.54 across the board.

[Monkeyjoe]

I think that is what you had said before in the other forum.  3.54.  to save money, I will wait to get home and check.  I only have the front end now to look at as the rear end is the one the wrecking yard installed so it will be stamped with the wrong size for the car.  I will have to re-stamp the rearend when I get the new gears in it for future repairs.  so nobody get confused.

At the time I had the wrecking yard put the axle into the car, I told him that an axle from 85 and newer wouldn't work.  He said he had this big book that wrecking yards use and he would trust it over anything and it told him that any year axle would work because they all had the same gear ratio.  I disagreed and told him the ratio will be stamped on the axle or on a tag.  I guess he just went with what his book said.  Now I cant hardly drive the car.  almost stalls out when starting in 1st gear and cant maintain speed in 5th gear, have to take all the hills in 1st or 2nd. 

[Prafeston]

From what I've heard the 5th gear isn't of much use unless you are on flat ground or going down a hill. I can't speak from experience though.

[Monkeyjoe]

5th gear has always been pretty good, before I rebuilt my iron duke, I had to hit the hills in 3rd or 4th, now with the wrong rear end, I hit the same hills in 1st or 2nd. 

With the correct rearend I was getting anywhere from 30-34 mpg, 5th gear works really well.

[captspillane]

Your old first gear is now exactly the same as your old second gear. The lack of first eats up your clutch and makes the car a nightmare to drive for someone uncomfortable with stick. Your current 4th gear is exactly the same as your old 5th gear. Now in 5th you need to be going at least 85 mph to upshift into it and at a low 2K RPM you'll be doing over 100 mph. Craziness!

Before you complain too much about how terrible your situation is, realize that your current gearing is the factory default for every single stickshift 258 Eagle and Spirit from the factory.

Just about every Iron Duke stickshift Eagle was 3.54 gears and just about every 258 stickshift Eagle was 2.35 gears. AMC claimed that it was a safety advantage to the higher gears because you wouldn't need to shift from first to second while turning left through an intersection. That's poppycock. Some AMC upper managment dooshwiggle made that decision in 1980 judging by the fact that my 1979 V8 AMX was 3.54. I drove my white SX4, black Spirit GT, and my current daily driver station wagon all with 258 T5s for a long time cursing that dang gear ratio. Your built up Iron Duke puts out as much power as a stock 258, so you can now appreciate how annoying it is to own a factory original 258 T5 Eagle.

At the end of the day you will want 3.07s with a T5 and 215 or smaller tires. With my 235/75R15 tires I prefer 3.54. With 225 size tires its a toss up and I'd prefer 3.54 over 3.07.

FYI All stickshift XJ's are 3.07 and all Automatic XJs are 3.54. I found 235 tires and 3.07 gears annoying in my XJ because the shift point between 4th and 5th is right at highway speeds so I had to shift with hills. Going to 3.54 lets you shift into 5th on the highway and stay there the whole time.

[Monkeyjoe]

Wow, that was awesome.   I love this forum.     I think in the Nest forum we determined it was 3.54 but that is all lost now.  That ratio worked really well with the new motor too.  Shifted to 5th right at 55 very comfortable from there up to 70,  we were able to put about 3000 miles on the new motor before the axle broke and started the whole wrong axle situation.    Fuel economy was great.

You are right, it feels like I am starting out in 2nd gear.  4th gear is way worse that what 5th used to be.  I cant even look at a hill in 4th gear now.  and fuel consumption from Colorado Springs was double.  I was only getting between 12 and 15 mpg, mileage was counted using actual miles, not the odometer reading or adjusted for the gearing difference. 

I worked many late nights trying to get that car ready for my wife to use as a winter car.   But The car has had to be parked since I left for deployment, and forget about using it in winter we cant put it into 4WD or we destroy the VC in the transfer case, however, my wife does go out and start it every month and drives it either around the block or to the grocery store and back, about 12 blocks.  The she parks it and plugs the battery maintainer back up.  She even put Stabil in it for me.  She is a gem.