cruzer

im debating a 4.0 vs a 4.7. will get a 4 inch lift and biggest tires i can fit. my guess is v8 will be better on the gas having the power to turn the big wheels.

i can get a 2003 4.0 tomorrow but really like v8s, thats all ive had. the sound, the power, but is the 4.0 more reliable?

ill be getting CAI, superchip and exhaust for sure. possibly throttle body if that matters in the debate of mpg 4.0 vs 4.7 after mods

E-Rok

dont buy a Jeep if you are worried about MPG lol

id rather have the V8 with the weight of a WJ and larger tires

cruzer

obviously im not worried about mpg but doesnt mean i want to be ignorant on choosing the engine. if they will get same mpg then i should get the v8 for the towing power because thats one of its uses.

if the 4.0 will still get 1mpg better than the 4.7 my atv doesnt weigh much the 4.0 should tow it fine

721

For the ZJ's, all three engines got about the same mileage (4.0, 5.2 and 5.9). I would assume that the same could be said for the WJ, as it had more to do with weight, gearing and aerodynamics then engine size. The 4.0 is obviously very reliable and could tow an ATV trailer just fine, don't know enough about the 4.7

bryweb

Personally I would not own a 4.7 because I have dealt in the past the (3) timing chain CRAP on a Dodge Intrepid I owned, also two very trusted mechanics who are friends of mine told me to stay as far away from them as possible.

But I know a ton of people who have them and love them - so if you get one make sure you replace the oil religiously would be my advice.

I love 4.0L I have had them in 4 Jeeps now, they turned 35's MTR's to clean the mud on my TJ, I have a buddy that tows his boat, his CJ5 on 44's and his Land Cruiser on tractor tires with a 4.0L WJ.... and he drives like a maniac and never has a problem.

But I do understand the whole V8 thing... and can not blame someone wanting one..... As I start planing taking my WJ to the wild side (Dana 44/9", 35 Tires, 6" Long Arm, Etc.) I am looking into doing a V8 swap - but it won't be a 4.7.

If you get a 99-2001 WJ 4.0L make sure it does not have the 0331 Cylinder Casting Head... RESEARCH IT - those head castings SUCK !!!!! Trust ME.....

Bryan

E-Rok

what does a dodge intrepid have to do with a 4.7?

bryweb

Because the 2.7L motor found in an Intrepid is the same design as the 4.7L in the Grand Cherokee - with 3 timing chains, over head cams, etc both made by the same company.

92notch

Ive owned both and both have been runing 35's and gas was about the same 15-18

bryweb

What gears were you running with the WJ, 35's and the 4.0L - and did the 4.0L have enough torque to spin the wheels in the mud to clean the tread?

My TJ 4.0 w/5spd, 4.56 and 35's had plenty, but the extra weight of the WJ with the Automatic has me a bit nervous as I plan my build..

PS: I never got over 13mpg on my TJ with 35's, although it was more of a brick in the wind.

Thanks,

Bryan

cruzer

tuesday im getting an overland which has the 4.7 HO. should work well with 32s or 33s and maintain decent gas mileage

austinjoe13

I'm talking about an XJ but my dad's 96 has great power even with 33s and 3.55s. I'm gonna follow suit to the 4.0 crowd and tell you everything else is crap . Just stay away from that quad drive II or whatever it's called.

1tonxj

I own a WJ that my brother wrecked into trees at 40-50 mph...It has 170k on the 4.7 motor/trans ...motor runs perfect no oil leaks/no burning oil trans had a leak in cooler line from wreck ,and still runs perfect ...4.7 is just as reliable as a 4.0 .

cruzer

why is that?

bryweb

This is how I remember it and can find from some quick research -

The NV247 the "QuadraTrac 2" or "Quadra Drive" Is a full time 4 wheel drive transfercase and actually has a larger chain which is nice, but uses a unique "gerotor coupling" to make it full time, (its sort of a clutch like in a limited slip axle uses to allow the front a back axles to spin differently in the transfercase), the PROBLEM is the "gerotor coupling" is VERY EXPENSIVE to replace (like $350 for the part alone as I remember), also the preferred NV242 is a (part time 2 wheel or 4 wheel ) and gets slightly better gas mileage. When my NV247 died in my 1999 WJ I replaced it with a NV242.

Personally I don't think its a big deal until or if the "gerotor coupling" blows unless your driving style off road lends itself to times of needing 2 wheel drive or you are trying to pinch every MPG out of your Jeep.

Bryan

austinjoe13

Yeah that's true. I know a guy who put three t-cases in his 99 in less than 100k miles.