5 speed standard transmission for my wagon

[wnlewis]

I would like to put a 5 speed transmission in my 1987 Eagle DL Station wagon. It has the regular automatic transmission in good shape.

What transmission would people recommend? I want to be able to pull an Airstream Caravel trailer. I know AMC would not set up the towing package with a standard transmission, but that could be done now with the right one.

Thanks,

Neal Lewis

[captspillane]

The AMC Towing package included a rear sway bar, 3.07 gear ratio axles, and rear bumper mounted ball hitch. The frame spacing on a Jeep Cherokee is identical to an Eagle, so I have mounted a Cherokee 2 inch reciever under mine. I used six grade 8 bolts  that went all the way through the frame so that the head was under the carpet inside the car.

I also took a Jeep Cherokee sway bar and compared it to my Eagle sway bar. The bar itself is identical. I did manage to fit the Jeep Cherokee sway bar into an Eagle by making a little L bracket and rotating one of the axle joints 90 degrees. In hindsight it wasn't worth the effort, you're better off finding a parts car with a sway bar. All Eagles have the holes already drilled on the rear frame.

The next thing you should do is buy Load Leveller shocks. I buy them from "wwwdotshockwarehousedotcom." They have a coil spring wrapped around the shock that will stiffen up the rear springs perfectly to tow with.

Here is my SX4 with the frame mounted 2 inch reciever:

[captspillane]

Your 5 speed options are as follows:
1) T5 transmission rated at 265 ft/lbs. This is the five speed original to Eagles and CJs. It is a very small casing and prone to breaking in a bunch of ways. It shifts very nicely and doesn't weigh much, but its really just intended for cars. Don’t get a T5 if you’re going to tow with your Eagle.

2) "World Class" T5 transmission. These are common in Ford Mustangs but do not adapt to our transfer cases easily. Some people take the Jeep T5 and swap in most of the "World Class" parts, but it’s not even remotely worth your time. When they're finished the case is still prone to warping under torque and it is still considerably weaker than an AX15 or NV3550.

3) AX15 Transmission rated at 285 ft/lbs: This is found behind the 4.0 in Wranglers and Cherokees from around 1990 to 1998. I forget the exact years. This transmission shifts very nicely and is also very strong. It’s very common and is the easiest transmission to find at a junkyard. Early AX15s had an internal slave cylinder and later ones are external. Either one works fine, but I would prefer the internal slave cylinder because it has a normal 3/16 double flare input versus the crazy pin and o-ring input the external slave cylinder has. You must use a 4.0 flywheel with this transmission because the 4.2 flywheel is a quarter inch thicker. The T5 clutch is the same, but the pilot bearing is different for the AX15 and NV3550. Instead of a brass plug the AX15 and NV3550 have a thin roller bearing pressed into an aluminum spacer that in turn is pressed into the end of the crankshaft. Make sure you get the roller bearing and aluminum spacer together, since you can’t remove the bearing without damaging the spacer. I first bought mine at Autozone and only the roller bearing part came. I then bought it at Advanced and the two came together for the same price.

4) NV3550 rated at 300 ft/lbs: This is the strongest five speed found in factory Jeeps. It replaced the AX15 around 2000 until 2004. Advance Adaptors sells the external slave cylinder with a stainless mesh flexible input line and the brass adaptors it needs. With that kit you just need to make a short piece of double flare brake line from your Eagle clutch master cylinder to the flex line. You must use the correct fluid or you’ll damage the synchros.

If you’re installing it behind a 4.2 or 4.0 you should retain the NV3550 bellhousing and 4.0 flywheel so that your fuel injection has a place for the crank sensor. If you’re installing it behind an AMC V8 you cannot use a 4.0 flywheel because V8s are externally balanced. In that case use an Advanced Adaptors kit that mounts between the NV3550 and a T5 bellhousing (Its basically a 3/4 inch thick spacer). That retains the bigger flywheel and all the original shift linkage.

5) NSG370 6 speed transmission rated at 272 ftlbs: This replaced the NV3550 in Jeep Wranglers. They’re very rare but not impossible to find. Only a NSG370 from a 2005 or 2006 4.0 Jeep Wrangler has the AMC bolt pattern. They still use the NSG370 today in Jeeps, but the bellhousing cannot be removed from the transmission so 2007 and newer Jeeps have a Chrysler bolt pattern and are useless to us. This transmission has a 4.46 first gear and a 0.84 overdrive in contrast to the 3.83 first gear and 0.79 overdrive in an AX15. This means that you should use 3.07 gears with a NSG370 to get the same shift points you would have with an AX15 mated to 3.55 gears.

6) AX5 transmssion: Its a very weak transmission easily confused with an AX15. Don't use it. Only 4.0 Jeeps have the AX15.

7) NV4500 rated at 460 ft/lbs: This is a true truck transmission. It’s literally twice as heavy as a T5, it shifts clunky like a truck, and it is easy to adapt to our engines and transmissions but it’s not easy to fit under our Eagle floorpan. This option should only be considered if you have a 401 in front of it and a custom Dana 60 axle behind it.

[captspillane]

Next thing to consider is axles. The rear axle in your Eagle has the same internal parts as a Jeep Cherokee, but the axle tubes are much smaller. They flex more and you will likely break an axle if you tow with your Eagle. The Dana 35 is also a C-clip axle, which means that your wheel can fall off if a tiny little clip breaks. I’ve had this happen to me, the entire tire and drum assembly just fell off the car. It will happen if you lean the car over on two wheels or jump the car airborne as often as I used to.

A Jeep Cherokee Dana 44 was a rare option. It is the perfect width for our Eagles and shares the 4.5 on 5 bolt pattern. This axle is a full floating axle that does not rely on a C clip to hold everything together. A Dana 35 is basically a car axle, a Dana 44 is essentially considered a 1/2 ton truck axle, and a Dana 60 is considered a one ton truck axle. There are companies that narrow a Dana 60, convert it to calipers, and convert it to 4.5 on 5 for about five thousand dollars. Some Grand Cherokees, especially the V8 ones, have a Dana 44 axle with calipers. It’s a common Jeep conversion to take the caliper and parking brake and axle assembly from a Grand Cherokee and put it on a drum brake Dana 44. I bought a Cherokee Dana 44 off the evil bay for 300 dollars and another one with factory limited slip for 350 dollars.

All my Eagles have 235/75R15 tires and 3.55 gears and its the perfect gear ratio in my opinion. This is the most common Jeep Cherokee gear ratio and it is easy to get this ratio when you upgrade your rear axle. The front axle is more difficult. Only 151 Iron Duke Eagles had 3.55 gears from the factory. You will need to find one of those front axles or find the thread here on the forum that talks about switching gears. There are three different front axle castings, so not all Eagle front axles will accept 3.55 gears. A lot of station wagons had 3.07 gears, including all the tow package Eagles, so those are easier to find.

-Dave Spillane-

[Bird-o-Prey]

WOW!  You asked...

[autumnglen]

WOW!  You asked...

thank you for sharing all the information, I printed it out for my personal archives, in case it gets lost later.
Rita