simon

I have a '00 model GC4.7V8. At some time in its life a previous owner has changed the front axle using one from a 2003 GC, I dont know what model. Is this likely to have the same ring and pinion ratio as the one that is suposed to be in my car? Will it make much difference if it is wrong?

Also, my dealer has advised me to change my tires so I have the same brand/tread pattern on each wheel or I risk damagint the transmission. Is this really likely?

Cheers

Simon.

dlundblad

If it doesnt have the same ratio, in theory your transfer case may get a little messed up from the front and rear axles going a different speeds... Not quite sure on that though...

As far as the tires are concerned, it should be ok as long a they are the same size on all four wheels, once again, you want all the wheels going the same speed for your transfer case's sake...

seed

yes,they must be the same gears or...bad things will happen. Your dealer "advises" you on that because thats what jeep says you must do with the "full time" 4WD t-cases,they have little tolerance for variations in tire size,especially quadra-drive

simon

So are the ratios in the fitted '03 axle likely to be correct for my '00 V8? It seems to drive OK. Is it worth getting all 4 wheels in the ait and doing a check to see the front and rear wheels rotate equally for one engine revolution?

dlundblad

They could or could not be... I feel that it is a good idea to check them... if they are off, it could cost a good hunk of change to replace/fix the the T- case...

simon

Sounds like a safe option. Whats the best way to check? Do I have to open the diff cover? Can I do my idea of counting revolutions?

dlundblad

Jeez, I have no idea... I would suggest taking it to a car place... but Im sure there is a way to check yourself...

simon

After reading a bit about this I have a plan...
Park in Neutral
make a chalk mark on all wheels and both drive shaft flanges
Push the car for one wheel rotation.
Check all wheels have turned the same
Check both drive shaft flanges have rotated the same ammount.
I will post on here how it goes......

seed

if you have the 247 t-case (AWD) and have been driving it for a while like that then the gears are the same,if they weren't it would be broken by now. Your not gonna be able to tell doing the DS/tire revolutions thing...you only have two gear options 3.55's or 3.73's the factory tag might still be on the axle to see.

93gc40

X2, if you have AWD TC, and the gears didn't match, you would have already broken something, and would know it. If you want to be sure, remove the covers and count the teeth on R&P, ratio may be stamped into the Ring gear.

tsconver

easiest to just raise it up and rotate the a wheel on the front and count how many times the driveshaft turns, it should either be 3.5 times or 3.75 times for one tire rotation. rinse and repeat on the rear. As mentioned most v8s have quadratrac and you would have destroyed it by now if you had mismatched gears.