you will need to raise the fan shroud, or add a body lift at the same time for the fan to clear with a MML. I have seen jeeps on the street with big time T-case drops. It doesn't really make sense to me to lift it, then lower the lowest point, but at least its cheap!
Good old launch shutter . Just put a 4 inch long arm kit on my 02 tj and got the same thing I changed the angle and dropped the tranny another 3/4 of an inch for a total of 1 1/2 inches . Ideal is tranny and pinion at the same angles . got rid of 90% of shake may still add a sye to get rid of the rest . If you drop tranny a bunch you may want to over fill with lube a bit because it has all run to the rear
85 cj7 51cj3a
Notice in the picture the front and rear u-joints have the same angle. For that type of driveshaft that's very important. Yours has the front joint bending lots more than the rear joint.
You might be able to eliminate most of the vibration, if not all of it, by going to adjustable length upper or lower control arms. Adjust so BOTH both u-joints are at the same angle.
A CV joint is entirely different - the rear angle should be straight and the front where the CV is, takes all the bending.
It's no wonder the country is falling apart - stupidity abounds!
Really, the best thing to do is install a SYE kit. All the trouble you have to go through just to get the least amount of vibration you can settle for, and you will likely never get it all out, and still you have to worry about popping that shortened driveshaft out of the back of the TC spline every time you get the jeep on a trail and flex a little anyway. I know, I've been there! Trust me you will never be fully content with your jeep.
If you cut corners what your left with is silly looking dropped crossmember, losing needed ground clearance, and all the other little gremlins you have to contend with like shift linkage and motor mount lifts, fan shrouds etc:. You will likely find you will spend more time, and probably nearly an equal amount of money messing around with all of those little PITA problems than just doing it right in the first place.
You can buy a good SYE, not a hack and tap, for around $250 online. I would go with the SuperShort SYE if you have the standard TJ because it allows for a longer driveshaft and it will help with the pinion angle. The CV driveshaft can also be purchased for a couple hundred dollars through several shops online, and if your budget is tight, go to your local Junker and buy a used front CV driveshaft from an 87-99 cherokee and take it to your local driveshaft shop and have it shortened to your dimension, these also work well and its an affordable solution to the driveshaft expense.
Its a half a day job or full day depending on your ability to turn a wrench. Its not too difficult to take out your TC and put the kit in, Ive done several of these by myself. Buy an $18 chiltons manual if you need help, or go online , there are tons of walk-throughs you can read for the 231 TC.
Look, you will not regret having spent the money to do a SYE. You know the job will be done the right way, it will be reliable and worry free when you need it to be while on the trail, and best of all it will not need any other mods, your trans crossmember will stay tucked up where it belongs, the shifter linkage will work perfectly and it will drive like a perfectly normal stock jeep with no vibrations when all is done. Save up the dollars and do it right, and Good luck!
your angle in the back is not too bad, they have to be on the same plane, or within 3 degrees, you might want to try and take out half of your tranny drop maby go to half an in, your shuttering on takeoff most likley is from your front shaft, it is a double cardin so your pinion has to point strait at the cardin joint or just a little bit under like .5 deg to 1.5 deg but never over, when it is pointed over it will make it shake when you take off, too much under and it will make it shake when you slow down, you can go to the home depo and buy an angle finder for 8.00 they sell them were they sell drills, theres a lot of people in these forms that dont know what there talking about and are just spewing out things they have herd and there are a few that really know what they are talking about, so dont get confused, well good luck with it man all you have left now is to dial her in, O one last thing it is allways a good idea to install new u joints when installing a lift lots of times its the old joints having to move in a dif plane that will make for some vibes
You might first want to get an external oil pressure reading on it to verify your gauge is working properly, the factory gauge and sending unit is not always very accurate and over time can become off.
The 4.0L is hard to kill, and if the previous owner changed the oil like he/they should have it might be ok.
The oil viscosity and age of the oil can effect your pressure reading too, so change it and filter out if you havnt done it already and make sure you use the recommended weight. Then recheck the pressure.
If your not visibly blowing out blue smoke when running, (burning oil) or having to replace oil between changes, and barring oil leaks (a little is ok,) your engine might be Ok
A lot of folks can push 250k plus out of the 4.0L if maintained properly.
Originally Posted by Apshouse
The mileage is 150000 I bought it from the original owner, when you start it in the morning it reads about 45psi but when it gets hot it only reads @ 8psi at idle driving at 2000 rpms it's @ 20 psi
99 TJ 4.0L Auto SS SYE, 4.5" Longarms 33"s BFG's Locked on a Turdy5
"""""theres a lot of people in these forms that dont know what there talking about and are just spewing out things they have herd and there are a few that really know what they are talking about,"""""
Yup - One just popped up!
Dropping the trans to equal out both angles would create problems -
Fan shroud interference -
Valve cover to firewall interference etc. -
Twisting of the motor mounts, creating early failure -
Shifter clearance problems -
Increased angles on the front driveline - transferring the vibration problem to the front -
Not to mention the T-case hanging down creating a clearance problem.
Obviously the best way is to go to a CV type driveshaft - and a SYE. But it's pricey!
Or simply rotate the rear diff snout down till it matches the front angle. By far the cheapest solution.
Here's a good explanation about angles and why they need to match. It's written by one of the respected driveline experts -- Tom Wood.
Just a thought- when I test drove the jeep before I bought it I dont recall it having a vibration or low oil pressure, shortly after I bought it I put it on a lift at work and changed the oil I used val. 10w30 high mileage and a mopar oil filter, I also replaced 1 tie rod end and tightened the locking nut on the front track bar that was loose. Than put it on the ground and after that I noticed the vibration on take off, maybe it was already there and I just dont remember. Or maybe raising it on the lift changed the angle somehow. I just don't know but it seems weird to me..
That's the trouble with multi-viscosity oils. The additive they put in makes it act like it's 10 weight when cold, and 30 when warm. The PO may have had much heavier oil in it - 40, even 50 wt oil - it may have been low before, that's why he used heavier oil.
You might try using straight 40 and see how it fares.
The vibration - could it be when you tightened and replaced those items you became more aware of any vibration?
A bent or damaged DS vibration is more pronounced the faster you go. Your complaint is under acceleration (load,) not speed.
During normal 2 wheel drive operation the front DS turns, but is not under load. Vibration would be constant whether accelerating, coasting, or decelerating.
The rear DS carries all the load. Problems in the rear DS, like bearings, or in your case, the angles of incidence, will be most pronounced under load - like acceleration. The harder you push it, the more it shakes.
It's no wonder the country is falling apart - stupidity abounds!