(4wd eagle?) Five speed automatic with overdrive- can it be done?

[SNOWMAGEDDON]

I ran across the link article below and some info on sx4 w/5 speed auto w/overdrive
does anyone know if that trans setup or any other will work with a 258 eagle wagon
sounds like a lot of fun for a long distance highway touring driver -


http://www.conceptcarz.com/vehicle/default.aspx?carID=19324&i=2

[shanebo]

Dimensionally it wouldnt be that much bigger than the stock 3 speed. I guarentee it could be done....Im sure some major adaptation would be involved but its do-able.

[captspillane]

The person who wrote that article thought that a five speed automatic was an option. That person was totally wrong. No five speed automatic existed as an option in 1982. A five speed MANUAL transmission was an option in late 1982 and 1983.

The only automatic transmission available as an option to a 151 Iron Duke was a Torqueflite 904 (with Chevy bellhousing pattern). The 6 cylinder cars got a torqueflite 998 (with AMC Bellhousing pattern). A 998 is a 904 with a number of minor items reinforced. Essentially 904= light duty, 998= medium duty, 727= heavy duty. All are three speed transmissions.

A five speed automatic in a Ford Ranger is exactly the same as their four speed, except that there are two possible second gears. In other words third, fourth, and fifth are universally about the same in all transmissions. There is no appreciable difference between a four and five speed. They will both have a single overdrive gear of approximately .7 to .8 ratio and the second highest gear will be 1.0.

The three speed transmissions do not have an overdrive. Their third is 1.0. There is an appreciable difference of about 4 MPG highway if you have low axle gear ratios of 3.07 or 3.54. There is no difference in MPG with 2.72 or 2.35 axle ratios because they essentially have an overdrive in third. The high axle ratios, however, are very slow at accelerating because they gain an overdriven third at expense of a low first. A four speed gives you the low first to accelerate and tow while still having the overdrive for fuel efficiency.

The only four speeds that will bolt right to a 258 are the AW4 and the later 4RLE. A simple adaptor kit also allows you to install any Chevy four speed transmission at the expense of about 500 dollars just for the adaptor kit. 1973 and 1974 Full Size Jeep trucks actually have that adaptor kit provided from the factory if you can find one. Most Jeep and Eagle guys will use the common Chevy 700R4 truck transmission because the AW4 and 4RLE are medium duty transmissions and the 700R4 is a very common very strong truck transmission.

[captspillane]

Yes, any transmission behind a 4.0 will bolt to a 4.2. There are only two four speeds ever offered behind a 4.0. Both are electronically controlled and tied into the fuel injection wiring harness. They are very complicated installations. They are called the AW4 and 4RLE.

The Chevy transmissions are much easier to install because the 700R4 isn't computer controlled. A newer version is. It can be a bolt on solution if you have the bellhousing adaptor. The catch is that the majority of Chevy transmissions use a totally different output shaft that doesn't work with Jeep transfer cases. You have to find a Chevy transmission from a truck that had a New Process transfer case. Those are actually pretty common. Otherwise you need another 450 dollar adaptor kit.

[carnuck]

AW4 is more of a bolt in than anything else and gives you two optins for O/D. .70 or .75 depending what year you get. renix years used .70

[doc65]

captspillane,

Actually that's not "quite" accurate, the ZJ Grand Cherokee initially used an AW4(93-94 & some of 95) behind the 4.0 engine, then the 42RE(96-98, it's basically an A500/TF with an overdrive tailhousing), then later yet the 42RLE(no relation to the 42RE) that was used in the Wranglers & I believe the WJ Grand Cherokee though haven't verified that last bit.

Doc

ps. I have a 42RE & a 44RE(ZJ with V8) in the garage right now that I'm going to Hybrid'ize together for my 96 ZJ with a 4.6 Stroker in it. The original 4.0/42RE was ok, but since the Stroker install I can break the clutches free in ANY gear.  With this hybrid, additional clutches & steels & a shift kit to speed up the shift instead of slipping it so much I should be good.   

[captspillane]

Ah, good to know. The 42RE has no relation to the 42RLE? I thought it was a minor difference in internal gear ratios. My 2006 TJ has the 42RLE but that is the limit of my knowledge with them. I'm going to have to search for comparison photos this week.

I understood the new Chrysler naming conventions use the first digit to express how may gears it has and the second digit to express a relative value in strength. I understood the 42RE to be conceptually equivalent to the medium duty TF998 with just an electronicallly controlled throttle body and overdriven tailhousing. Likewise I understood the 45RE transmission (not available with an AMC bell pattern) to be equivalent in strength to the heavy duty TF727. The ZJ 44RE (Also not available with an AMC bell pattern) is supposed to be stronger than a 998 but weaker than a 727.

I have never found a torque rating in ftlbs for those transmissions with the Chrysler naming convention. There is a torque rating available for all the others that I researched. I wish I knew what made something a "44" versus "45" in torque rating to compare to all the other options available.

I would be very interested in information about giving the additional strength of a "44" transmission to the "42" transmissions. Ideally I would love to pick up a Dodge truck "45" transmission and join it with the "42" transmission, but I have never seen the two next to each other for comparison. Right now the 700R4 is the clear choice if you want the strength of a TF727 with an overdrive. This information could change that. Thanks!

[doc65]

Here's a couple quotes:

Originally Posted by WIKIPEDIA

A500

The A500, later 40RH/42RH (hydraulic) and 40RE/42RE/44RE (electronic), was an A904 derivative used in trucks and vans. Introduced in the 1989 model year on a limited basis, it was the first light-duty Chrysler four-speed automatic and was placed behind the 3.9 L and 5.2 L engines for light-duty purposes. A tailshaft overdrive unit was bolted to the rear of the case to provide a total of four forward speeds, and was replaced by the 42RLE in 2004.

Gear ratios:

-1-----2----3-----4-----R
2.74 1.54 1.00 0.69 2.21

Applications:

1989-2001 Dodge Ram pickup 150/1500 V6/V8(2WD)
1989-2003 Dodge Ram Van B150/B250 V6/V8
1989-2003 Dodge Dakota
1993-2004 Jeep Grand Cherokee I6
1996-1998 Jeep Grand Cherokee 5.2 V8
42RLE


The 42LE was modified in 2003 as the 42RLE, originally for the then-new Jeep Liberty. It is a 42LE transaxle, modified for RWD use by removing the integral differential and transfer chain. Power flow exits the rear of the now transmission. The case has also been modified. This transmission is still in production for several models. Applications:
42RLE
2005–present Chrysler 300
2006–present Dodge Charger
2004–present Dodge Dakota
2004-2009 Dodge Durango
2005-2008 Dodge Magnum
2007–present Dodge Nitro
2003–present Jeep Liberty
2003–present Jeep Wrangler
2009 Dodge Challenger V6

You are correct in the numbering scheme, 44RE  is 4 forward, strength 4, Rear drive, electronic; 46RH, 4 forward, 6 strength, Rear drive(4x4 still follows rear drive in this case), HYDRAULIC(46RH is used in full sized dodge trucks & vans), 47 or 48 is used behind diesel.

The internal differences in the 42/44 are that each clutch pack gets an additional friction & steel disc as well as an additional pinion gear is two planetaries. The 46 RH internals can also be put into a 42RE case so that it can be mounted  to the 4.0/4.2 those also get more discs & steels, but also larger diameter, it's much more work though. and way overkill even on a potent stroker.  I've not seen a 45...

[shaggimo]

Careful on the 700r4, they are a ticking time bomb in stock form depending on year (the early ones are garbage at best). Granted a 258 probably would never tear one up in stock form, but why would one go through the trouble putting one behind a stock engine   . They can be built to handle some serious abuse though, a rebuild with updates, and quality internals are a must.

[Sunny]

Right now the 700R4 is the clear choice if you want the strength of a TF727 with an overdrive. This information could change that. Thanks!

A TF727 is miles ahead of a 700R4. Keep in mind a 727 is a 'heavy duty' transmission.

Like Shaggimo said, the early 700R4's are weak. A 258 couldn't tear one apart, but anything with a bit more power will. Even a mild SBC will destroy them. The only advantage of a 700R4 is the 4th overdrive gear.

If I remember correctly, GM rated them for a max of about 300FT/lbs Pre 1987.
The ones behind an L98 were a little bit stronger, but that motor was still pushing near the limits of reliability torque wise.

The up side, is there is a lot of companies and kits who offer rebuilt kits to make them bulletproof.
I've got a friend with a Bowtie 700R4 Stage III, pushing 650HP in a Vortec supercharged Iroc, and he's put 30K on it so far with no issues.

Without exaggeration, I've seen a TF727 handle over double the torque that would turn a 700R4 into a pile of scrap.

I've owned probably 5+ cars with a 700R4 and anytime I start modifying them, it doesn't take very long to start loosing gears. Even on a fresh stock spec rebuild.

[captspillane]

A torque rating of 300 ftlbs for an automatic is dismal. Wow that's terrible. The source I read must have been dead wrong. It suggested that the TH400, which shares the exact same torque rating as the TF727 of 450 ftlbs, was the grandpappy of the 700R4 and that the 700R4 had the same exact strength with the addition of a fourth gear.

I'm interested in a automatic with a fourth gear that is strong enough to live behind a well built AMC V8. I'm rather interested in the concept of using a AMC casting "42" and swapping in the internals from a "46" or "47." That is something I will have to research thoroughly. Is there a Chevy four speed automatic transmission exceeding the strength of the 727? Obviously the 700R4 is not.

[shaggimo]

The 4l80E is the th400 relative, but, putting one behind an engine without a computer system is no cheap task, but it is do-able.

[doc65]

Of course I can't find it right now when I'm looking for it, but there is a very endepth writeup about the 46 into 42 case rebuild out there on the web somewhere, it was related to a Grand Cherokee (ZJ) install.  I'm sure I have a link ot it on one of the computers/laptops, just gotta search a little

Doc

[shaggimo]

captspillane: forgot to add, the th400 was GM's stout three speed tranny, which was the one they used behind their big block cars and HD trucks (closest of the gm offerings to the strength of a 727). The 4L80E is the electronic replacement 4 speed for this tranny. There are companies out there that offer the the computer and harness to retro fit one into an older car/truck, but as I mentioned previously, it's pricey to say the least. I'm sure with a little trickery, one could come up with a shifter to control it manually, but of course without the computer doing the work, it would always have to be controlled manually (which could be good or bad, depending on how you look at it).

[carnuck]

A torque rating of 300 ftlbs for an automatic is dismal. Wow that's terrible. The source I read must have been dead wrong. It suggested that the TH400, which shares the exact same torque rating as the TF727 of 450 ftlbs, was the grandpappy of the 700R4 and that the 700R4 had the same exact strength with the addition of a fourth gear.

I'm interested in a automatic with a fourth gear that is strong enough to live behind a well built AMC V8. I'm rather interested in the concept of using a AMC casting "42" and swapping in the internals from a "46" or "47." That is something I will have to research thoroughly. Is there a Chevy four speed automatic transmission exceeding the strength of the 727? Obviously the 700R4 is not.

700R4 is a TH350 with an O/D tacked on.
The true weakness of the 42RE is the rear of the case. I've seen several now with the web torn out due to the torque of a heavy takeoff while hauling a trailer or downshifting manually while loaded. Another that was torn up while doing a brake stand.

AW4 gets a bad rep, but it is easily stronger than the 700R4 in stock form. Isuzu even uses a slightly beffier version in their NQR trucks with a turbo diesel. Some of the overseas Isuzus came with the same version of AW4 and 2.8 or 3.1L turbo diesels (I'm trying to see if I could afford the setup for my extended cab Comanche)