AW4 Behind a 258

[89 MJ]

Long story short, this summer I am going to get my first car back. It is an 86 AMC Eagle with a 258, 3 speed auto, and 2.73 gears. My plan for the car is to lift it enough to be able to clear a 235/75R15 tire and regear it. In order to make it a pleasant driving car, I also want to swap in an AW4 or some other transmission with overdrive. 

 

So to any of you CJ or other Jeep guys, what is the best route to go for an automatic transmission with overdrive? Would an AW4 be the best option since it will bolt up or should I look at something that is not electronically controlled?

 

So far, I haven't come up with much for any overdrive AT options, and I'm wondering if any of you have experience with this.

We are also considering doing a 4.0 head and fuel injection swap, in which case I would be able to use an AW4, but at this point I want to do my research as if I am keeping the carb.

An AX-15 swap isn't off of the table, I would just rather keep an automatic in this one. 

[Strokermjcomanche]

I seen someone use a AW4 behind a 258 before. What he did was use a TPS on the throttle cable so the AW4  knew where to shift at. I seen the car in person, but can't give you much more info than that. I can try to go back through some of my messages and try to find the guy, maybe has a post somewhere showing how he did it. His  father owned a jeep dealership. 

[Strokermjcomanche]

I found him and sent a message

[scaleless]

Automatic transmission?

[89 MJ]

2 hours ago, Strokermjcomanche said:

I seen someone use a AW4 behind a 258 before. What he did was use a TPS on the throttle cable so the AW4  knew where to shift at. I seen the car in person, but can't give you much more info than that. I can try to go back through some of my messages and try to find the guy, maybe has a post somewhere showing how he did it. His  father owned a jeep dealership. 

Interesting. Thank you for the info and for checking with him.

 

2 hours ago, scaleless said:

Automatic transmission?

I know, I know, I prefer 5 speeds too, but the pedal assembly is hard to find for these cars and I want to keep this car similar to how it was when I had it the first time. Its the same reason I want to keep the IFS

[Caish]

TPS mentioned... 

Need to have a TCM also unless you plan on making it switch selectable. 

[89 MJ]

31 minutes ago, Caish said:

TPS mentioned... 

Need to have a TCM also unless you plan on making it switch selectable. 

Thank you

[Eagle]

In the days of the old XJ forum -- before it died and was reborn as NAXJA -- we had a frequent contributor named Frank Swigert who had been, IIRC, an engineer of some sort at AMC. He had a an AMC Eagle with an AW4 in it. He controlled it manually with a 6-position rotary switch to trip the shift solenoids.

 

[89 MJ]

4 hours ago, Eagle said:

In the days of the old XJ forum -- before it died and was reborn as NAXJA -- we had a frequent contributor named Frank Swigert who had been, IIRC, an engineer of some sort at AMC. He had a an AMC Eagle with an AW4 in it. He controlled it manually with a 6-position rotary switch to trip the shift solenoids.

 

Interesting. I am hoping to have the transmission completely automatic though. Otherwise I might as well AX-15 swap it. 

[cruiser54]

Why not keep the A904?

It has a lockup torque converter.

And your gear ratio is higher than the moon.

[89 MJ]

2 hours ago, cruiser54 said:

Why not keep the A904?

It has a lockup torque converter.

And your gear ratio is higher than the moon.

I want to regear it to run larger tires and make it so it can almost keep up with some modern vehicles. Plus I want it so I can have the power to tow if need be.

[cruiser54]

I'm not seeing what that has to do with an AW4. 

[89 MJ]

17 minutes ago, cruiser54 said:

I'm not seeing what that has to do with an AW4. 

I want lower gears but also want to drive on the highway, so I want overdrive. 

[cruiser54]

well, here's my experience. 81 Eagle Wagon limited. Had high gears like yours. Put 3.54s in it. Little bigger than stock tire. Towed a heavy tent trailer from Arizona to Colorado and back. Worked great. Also Prescott to Tucson and back. 

[89 MJ]

29 minutes ago, cruiser54 said:

well, here's my experience. 81 Eagle Wagon limited. Had high gears like yours. Put 3.54s in it. Little bigger than stock tire. Towed a heavy tent trailer from Arizona to Colorado and back. Worked great. Also Prescott to Tucson and back. 

Do you remember what kind of fuel mileage you got, even while regular driving with the 3.54s and slightly larger tires? Of course, I’d rather keep the stock trans, but it needs to be semi fuel efficient for me to justify having it and using it everyday. 

[cruiser54]

It was my wife's daily driver. Keep in mind 3.54 is what a Cherokee with an automatic has.

Fuel mileage was just fine. 

[89 MJ]

1 minute ago, cruiser54 said:

It was my wife's daily driver. Keep in mind 3.54 is what a Cherokee with an automatic has.

Fuel mileage was just fine. 

Thank you, I know that Cherokees also have AW4s. Maybe it makes the most sense to do gears and tires before doing the trans swap. That gives me time to save up some money anyways. 

[cruiser54]

Exactly. 

[89 MJ]

1 minute ago, cruiser54 said:

Exactly. 

Thank you for the help. Since you had an Eagle, I may lean on you when I have questions. 
Did they have the same rear end as an XJ? I know they both were SOA, I’m not sure if the axles would be a bolt in swap. I know the front isn’t because the Eagle front is IFS. 

[cruiser54]

Dana 35 in the rear like many XJs. Dana 30 in front but in an IFS configuration.

 

I have all the engineer's hand written notes and part numbers for putting an AMC V8 into an Eagle......

[89 MJ]

1 minute ago, cruiser54 said:

Dana 35 in the rear like many XJs. Dana 30 in front but in an IFS configuration.

 

I have all the engineer's hand written notes and part numbers for putting an AMC V8 into an Eagle......

Thank you. I wasn’t sure if I could bolt an XJ 44 or 8.25 into the Eagle for a strength and gearing upgrade. 
Those notes must be extremely cool!

[cruiser54]

The 35 will be fine in an Eagle. 

 

[eaglescout526]

3 minutes ago, 89 MJ said:

I wasn’t sure if I could bolt an XJ 44 or 8.25

The Eagle used the AMC35 which is a bit more stout than the 35 we all know and love. 

[89 MJ]

2 minutes ago, cruiser54 said:

The 35 will be fine in an Eagle. 

 

Holy cow. That is super cool. Priceless to an Eagle guy. 

[89 MJ]

1 minute ago, eaglescout526 said:

The Eagle used the AMC35 which is a bit more stout than the 35 we all know and love. 

Interesting. I remember discussing the D35 vs AMC35 in Chunks build thread. I know the 35 would be fine, especially considering my driving style, but I can get a D44 or 8.25 for the same price as a 35 at the metal recyclers. And the D44 would still look and be mostly correct for it. An AMC 20 would be ideal though.