Help! Pinion seal problem.

I have a 1990 Jeep Cherokee 4wd (3.55). My rear pinion seal started leaking bad last night. So I got a friend to help me replace it. However he did not mark the nut before he removed it. Now we have no idea what the original position of the nut was on the yoke. What do we do? We are doing this on our backs in the driveway, so I was hoping to avoid completely taking it all apart. Is there a torque we can tighten to that will be pretty close to correct?

If it's a d35 from what I understand you have to replace the crush sleeve whenever you take the pinion nut off. The only way I know of getting the correct load on the pinion is to take it all apart but you might be able to do it without I don't know.

There is no easy answer for your question. So I will describe my personal hacker/flat rate mechanic way of doing it. 2 words "Impact Gun". I have found that "most" impact guns have a difficult time crushing the crush sleeve without really trying. So just gun down the nut untill you see the socket start to slow down, and then stop. This is far from an exact setting, but will be close enough for most situations. No impact gun? Just tighten the nut with a large ratchet untill you feel it start to get real tight, then stop there. Another way to check is to tighten the nut down untill all the side to side play is gone, then just make sure is good and tight. No need to replace the crush sleeve at this point, it will take a good deal of effort to crush the crush sleeve too far. There is maximum torque spec, but this nut is usally tightend down untill you get the proper pinion turning torque when initially building the diff. There is a fine line between play in the pinion bearings and overloading the bearings, just go slow and you will be OK.


Bryan.

Tighten it back to about 250 ft-lbs. Your torque wrench probably only goes to 150, so 250 will be to the end of the scale (or to "Click") plus a bit.

Usually takes around 300 ft-pounds to crush the sleeve and set the preload.

With jack stands under the axles, tires and brake drums off. With the nut tightened properly and after a couple of turns to get things seated, you should be able to turn the yoke with three fingers without straining anything, believe the spec. is like 8 inch pounds of pre load on a used bearing (that´s with the nut on the yoke tightened properly). A new bearing is 15-35 inch pounds, this tells me, that a little loose is better than too tight.
Like Brian said, tighten until all the up/down play is gone from the bearing and tighten a little more, in small increments, occasionally turning the whole works a few times to seat everything. When you start to feel resistance to turning, with your fingers or an inch pound torque wrench, stop. If I remeber correctly, the torque on the nut, should be five foot pounds more, than the torque required to loosen the nut (next time record that number, mark the nut, shaft and yoke). In effect after every thing is seated (the yoke has no side to side or up and down play), it takes very little additional torque, to be close, to were you want to be.
I don´t know how they did it, but more than a few guys have asked for help, with there pinion bearings jammed in the race or way to tight. Always assumed it took like 250 foot pounds of torque, to crush the sleeve (hanging on a torque wrench with your rear in the air). Don´t know how they managed that much torque, with a ratchet. But a really tight pinion bearing, will overheat and fail pretty quick.

As 8Mud writes, the spec for setting up a new crush sleeve is the torque in inch-pounds to rotate the pinion. BUT ... that's measured with no ring gear or carrier or axles to turn, so you can't use that as a guide when the differential is all assembled.

Just checked with a fellow member who's a former Jeep tech. He confirms 250 ft-lbs

Just pulled these specs from the Chrysler Techconnect website.....

DESCRIPTION TORQUE
Bolt, Diff. Cover 41 N·m (30 ft. lbs.)
Bolot, Bearing Cap 77 N·m (57 ft. lbs.)
Nut, Pinion 271 - 474 N·m (200 - 350 ft. lbs.)
Screw, Pinion Mate Shaft Lock 16.25 N·m (12 ft. lbs.)
Bolt, Ring Gear 95 - 122 N·m (70 - 90 ft. lbs.)
Bolt, RWAL/ABS Sensor 8 N·m (70 in. lbs.)



The torque spec is 200 to 350 ft lbs. That is a big window. When I build differentials, I use the pinion turning torque method for setting the pinion bearing preload. This is the only way to be sure of getting the proper preload. The torque spec is to ensure that the nut will not back off(too loose), and that you will not strip out the threads for the pinion nut(too tight).


Just for kicks, here are the pinion preload specs, among others...

DESCRIPTION SPECIFICATION
Axle Type Semi - Floating Hypoid
Lubricant SAE Thermally Stable 80W - 90
Lubricant Trailer Tow Synthetic 75W - 140
Lube Capacity 1.66 L (3.50 pts.)
Axle Ratios 3.07, 3.55, 3.73, 4.11
Differential Bearing Preload 0.1 mm (0.004 in.)
Differential Side Gear Clearance 0 - 0.15 mm (0 - 0.006 in.)
Ring Gear Diameter 19.2 cm (7.562 in.)
Ring Gear Backlash 0 - 0.15 mm (0.005 - 0.008 in.)
Pinion Std. Depth 92.08 mm (3.625 in.)
Pinion Bearing Preload-Original Bearings 1 - 2 N·m (10 - 20 in. lbs.)
Pinion Bearing Preload-New Bearings 1.5 - 4 N·m (15 - 35 in. lbs.)


The only way to be sure, like Eagle said, is to take out the carrier and reset the pinion bearing pre-load with a dial type torque wrench. If you don't want to, or don't have the tools to do the job right, you just need to wing it.


Bryan


OK here is the proper way to service the pinion seal, as per Chrysler.

PINION SHAFT SEAL
REMOVAL
Raise and support the vehicle.
Remove wheel and tire assemblies.
Remove the brake drums. Refer toBrakes, for proper procedures.
Mark the propeller shaft and pinion yoke for installation alignment reference.
Remove the propeller shaft from the yoke.
Rotate the pinion gear three or four times.
Measure the amount of torque necessary to rotate the pinion gear with a (in. lbs.) dial-type torque wrench. Record the torque reading for installation reference.
Using Holder 6958 to hold the pinion yoke, remove the pinion nut and washer.
Use Remover C-452 and Wrench C-3281 to remove the pinion yoke Pinion Yoke Removal
Use a suitable pry tool or slide hammer mounted screw to remove the pinion gear seal.
INSTALLATION
Apply a light coating of gear lubricant on the lip of pinion seal. Install seal with Installer C-3972-A and Handle C-4171 Pinion Seal Installation
Install yoke on the pinion gear with Screw 8112, Cup 8109, and Holder 6958 Pinion Yoke Installation
CAUTION: Do not exceed the minimum tightening torque when installing the pinion yoke at this point. Damage to the collapsible spacer or bearings may result.

Install the yoke washer and a new nut on the pinion gear and tighten the pinion nut until there is zero bearing end-play.
Tighten the nut to 271 N·m (200 ft. lbs.)
CAUTION: Never loosen pinion gear nut to decrease pinion gear bearing rotating torque and never exceed specified preload torque. If preload torque or rotating torque is exceeded a new collapsible spacer must be installed. The torque sequence will then have to be repeated.

Rotate the pinion shaft using a (in. lbs.) torque wrench. Rotating torque should be equal to the reading recorded during removal plus an additional 0.56 N·m (5 in. lbs.) Check Pinion Rotation Torque
If the rotating torque is low, use Holder 6958 to hold the pinion yoke Tightening Pinion Shaft Nut , and tighten the pinion shaft nut in 6.8 N·m (5 ft. lbs.) increments until the proper rotating torque is achieved.
CAUTION: If the maximum tightening torque is reached prior to reaching the required rotating torque, the collapsible spacer may have been damaged. Replace the collapsible spacer.

Align the installation reference marks on the propeller shaft and yoke and install the propeller shaft.
Add gear lubricant to the differential housing, if necessary. Refer to the Lubricant Specifications for gear lubricant requirements.
Install the brake drums. Refer toBrakes, for proper procedures.
Install wheel and tire assemblies.
Lower the vehicle.

Thank you to everyone for replying. I found Brian C. and Eagle's advice to be the most helpful for my situation. It isn't perfect, but it seems to drive ok. I drove it for 70 mi last night without a problem.