Is overdrive feasible on '91 GW?

[TheGossert]

My gas mileage is atrocious (8-9 mpg). Fuel injection and/or overdrive would certainly help. I had overdrive on my old Austin Healey and I believe it was a stand-alone unit, separate from the tranny. I wonder if a unit like that would work with my tranny.

[gsmikie]

i did not think about that let us know if it makes a diff after you get the austin bolted in the wagon......should be room for it

[FSJeeper]

There are a number of ways you can get OD in your wagoneer. None of them are less than $2000 unless you are lucky finding used parts cheap. Gear Venders makes a bolt on OD, but expensive. You could have a 700R4 or 4L80 swapped in, but expensive. Even with the swap, it would take a long to to recoup your investment in an OD setup.
Plus, if you are running hig gears (low numerically), you will have to swap those too. Add at least $800 for that.

[mdill]

Well is feasable ? yes, is it economical, practical ? probibley not.
What is the goal ? If it is just saving gas money, forget it, it would
take a long time and a lot of gas to pay the $1000 + to get an
overdrive under there. You will be $ ahead figuring out why you
are not getting the 12+ mpg that you shoud be getting (kinda
sorry but that is about what you should be getting)

Mike D.

[gsmikie]

oh welcome to the board

[The Anti-Chrysler]

Your cheapest alternative would likely to be to use a clean boneyard TH-700R4 or early '90's (non-electronic) 4L60 from a fullsize GM truck. You don't need a 4L80 series tranny in a Wagoneer, unless there's serious circumstances (like towing houses or running 44's). You can get the adapter plate to use the GM tranny with your AMC engine, and either use a GM transfer case and adapt the driveshafts (GM uses slip yokes at the rear), or use an adapter to retain your transfer case. You're not going to be doing this swap for mileage alone - as said above forget it for that reason. What you would get also, though, is a decent performance improvement in that the TH-700R4 has a 3.06:1 first gear ratio (much lower than your Chrysler tranny) which will give you a good boost in acceleration. It would help compensate for that lousy axle ratio (if you have the 2.73's), but when in OD, you'd have almost no power unless you had the 3.31's. A 700-R4 has a 0.7:1 OD, vs. a 1:1 D for the 727 in your Wagoneer.

I can't see you getting away with this swap for less than a grand. Probably more.

[joe]

With your stock axle ratio(2.73 std or 3.31 opt) the tranny would constantly be kicking out OD anyway. With 2.73's it'd never stay in OD.
My little XJ which has a 3.54's and OD is constantly kicking out of OD at the first sign of a rise on the road. It's not bad on long runs on the interstate but even in that rig which is a lot lighter and prolly a better hp/wt ratio 3.54's are boaderline on anything but flat ground.
How worn out is the motor, total miles? When was the last time you did a full tune up? Cap, rotor, wires blah blah? You should be getting better than 8-9 mpgs. Granted not much better but in the 10-12 mpg range. Keep in mind one Wag weighs about what two Healey's weigh. Curb weight with you in it is almost 5000 lb and with the aerodynamics of a barn you're not going to get much better. I'd find out why your mpgs are poor before talking thousands of dollars for trannies, fuel injection etc. Neither of which will rebuild the motor or tune it up for you.
I'm not trying to be rude just honest...but if you can't live w/10-11 mpg's you prolly bought the wrong type of vehicle and should be looking for something smaller and lighter.

[TheGossert]

I just bought this 91 GW from a local new car dealer for only $1700, so I have $$$ leftover for repairs and upgrades. The odometer says 123,000 miles, but the Carfax report indicates "SUSPECTED ODOMETER FRAUD". Which means, I have at least 180,000 miles. Nonetheless, the car was well taken care of. The paint is glossy, but there is some surface rust. I love the car and I'm gonna keep it. If I can only reach 10 or 11 mpg, I'd be thrilled. I'll start with a tune up. By the way, my previous ride, 1998 Isuzu Trooper, was also a pig on gas: 13 mpg city.