Replaced front pinion seal today (1 Viewer)

[Kernal]

The front pinion seal on my 96 FZJ-80 has been seeping for awhile so replaced it today. I marked the pinion nut, pinion shaft, flange, and 3rd member before starting the job, and I noted that there was barely one thread of the pinion shaft showing past the pinion nut. With the vehicle on it's wheels, parking brake set, I took a 1/2" impact and 30 mm impact socket and slowly, a tap at a time, removed the pinion nut. I had tried first to pry up the staked area of the nut using a small punch but that wasn't happening. I held the flange all the way over in the direction of rotation with my free hand to take out the normal slack in the system figuring it might help prevent everything from bouncing around from the impact wrench, FWIW. Once the pinion nut was off the pinion flange slid back and off the pinion shaft splines easily by pulling straight back, no hammer needed.

I removed the pinion seal using a standard seal puller and a large screwdriver; it popped out after a few tries. Removed the oil slinger just using a screwdriver to back it out; easy as it's not attached to anything, that exposed the rear pinion bearings. The bearings were firmly in place so didn't disturb them but they looked normal FWIW. The pinion shaft was tight, no slop at all at 312,000 miles.

Cleaned the splines on the flange and the pinion shaft, greased them up, greased the lips of the new seal and the back side around the spring, replaced the oil slinger after putting a smear of grease on both sides where it's pinched in place by the flange and bearing, and cleaned the housing where the seal sits. I popped the new seal in using a hammer and a short PVC pipe connection ( 2 1/2" IIRC) as a seal installer. Initially the seal went in crooked but it straightened out once it was all the way in.

Didn't notice until it was all done but I believe I drove the new seal deeper than the original by maybe 1/16 inch (the FSM says it should be 1mm deep). There's a lip in the housing to stop the seal from going too far back, but apparently the previous (?original) seal was more flush to the edge of the housing. Either way that might turn out to be a good thing as the flange did have a wear groove from the old seal so with the new seal set a bit deeper the seal lips should not ride in the wear groove.


Here's some photos to document the process:

The top photo is what you'll be staring at after removing the front driveshaft (I added the marking paint). The middle photo is what you see after removing the pinion nut and flange however the photo was taken after my first few tries to pry it out hence the deformed lips. Bottom photo shows a wear groove in the flange.

 

[Kernal]

Top photo shows some rust and crud in the splines of the flange, I cleaned and greased these before reassembly. Middle photo shows the relationship of the oil slinger to the flange; when installed the slinger is right up against the rear bearings shown in the bottom photo.

 

[Kernal]

Seal part number, greased up new seal (greased the back side also around the spring), and the seal in place just before installing.

 

[Kernal]

My seal installer: the seal suddenly shot in crooked after a light tap on the low side (middle photo) and I was sure I had messed it up but as I tapped the high side in the seal straightened itself out. The bottom photo is a bit deceiving, the seal is not too high on the left however it felt a fraction higher at the bottom but would not tap in any deeper.

 

[Kernal]

Pinion flange cleaned and greased up before sliding it back on. The marks on both the flange and the 3rd member helped align the pinion flange back to it's original orientation. The middle photo shows the pinion nut before my last pull on the breaker bar, while viewing it from below it appeared like it needed to go a bit further. The last photo shows where the pinion nut ended up after my last pull, maybe ? 3/32 of an inch past where it had been staked originally. I could tell on that last pull that the nut was not going any further. So did I take up some slack that developed over the last 312,000 miles, or did I overtighten it?? I re-staked the pinion nut after the bottom photo was taken.

Edit: my recommendation would be to also mark the outside of your socket so it lines up with the pinion nut mark; that way as you tighten the socket you can watch the mark on the socket as the socket/pinion nut reaches the original position marked on the flange. Not the expert on this, but IMHO in this situation when you are just replacing the seal on an already built/used/preloaded pinion (and not using a beam type torque wrench) it is better to go a just a fraction (however small) past the original mark. As I understand how it all works, if you go short of the original mark you will end up with no preload at all on the pinion bearings as the crush sleeve has already been crushed. Any experts please correct me if that's in error.

 

[inkpot]

I don't like to re-use the nut. The divots in it can distort the pinoin threads on re-applying it. You should be setting that nut by TORQUE value, not but old position. JOhn

 

[Kernal]

IIRC FSM method would be to check rotational torque before removing the pinion nut and getting it back to the same value after, but that would have meant removing more stuff so I went this route figuring if I got the original pinion nut back to were it was before it should be good.

 

[js93cruiser]

I usually torqu it to 130ftlbs and steak it it's not enough to crush the crush sleeve but enough to keep it tight

 

[Kernal]

I was using a 1/2" drive breaker bar about 20" long so probably didn't exceed that number. As mentioned above I could feel on the last pull of the bar that the pinion nut wasn't going to move any more without a larger bar. I figure that means I probably got it back to where it was before in relation to the crush sleeve, but it did go a tad past it's original position; just don't know how much that would change the preload on the bearings. Guess if I had used a beam type torque wrench I could have compared the numbers in relation to the pinion nut depth. Oh well.

 

[Tools R Us]

There are two types of pinion setups:

I don't like to re-use the nut. The divots in it can distort the pinoin threads on re-applying it. You should be setting that nut by TORQUE value, not but old position. JOhn

This is correct for the spacer type setup (like on the early diffs), but if this is stock it is a crush sleeve setup.

IIRC FSM method would be to check rotational torque before removing the pinion nut and getting it back to the same value after, but that would have meant removing more stuff so I went this route figuring if I got the original pinion nut back to were it was before it should be good.

How you did it is how I would do it on a crush sleeve setup. Going slightly tighter will restore preload lost from age/wear. It has slight risk, the bearing may not be happy, if so, will tell you by grumbling, whining, etc.

The "correct" way is to drop the third, pull the carrier, push out the pinion, inspect the bearings, install a new crush sleeve and set the preload. This is a significant job, so IMHO, the short cut is worth the risk. If the bearings start talking, will have to do the full job.

 

[Tenzig Norgay]

I have the rear pinion seal in hand, about ready to do this on the original with 345k on it. Thanks for the pics and step by step. Does the back end have the oil slinger on it as well?

 

[Kernal]

Haven't done the rear myself but the FSM shows an oil slinger. The FSM also refers to a plate washer ? under the front pinion nut but there wasn't one, so thinking that's a typo??

 

[landtank]

I have the rear pinion seal in hand, about ready to do this on the original with 345k on it. Thanks for the pics and step by step. Does the back end have the oil slinger on it as well?

The two times I tried to replace the rear pinion seal it was more of a job than just that.

Look at the upper rear control arm on the right side of the vehicle and see if you can see some oil spray.

On the two diffs I took apart there was some spray up there and when I removed the pinion nut the pinion itself fell in to the diff.

The leak was from a bad pinion bearing which allowed the some wobble and subsequently the oil leak.

 

[Tools R Us]

^^^ Yep, pinion bearing failure will cause seal leakage, but so can simple seal wear, so IMHO the quick way is worth a try. If it fails, just have to do the whole job.

 

[Tenzig Norgay]

Great, exactly what I wasn't hoping to hear. The upper rear ps control arm looks like someone took it off and used it to stir a 50 gallon drum of roofing tar. If the pinion falls in, can I plug the hole, drop the shaft, and lock the center diff for a while?

I would imagine the third has to come out or I risk catastrophic damage.

 

[Kernal]

Is it wet with gear oil or grease from the rear U-joint?, got a photo??

 

[landtank]

Great, exactly what I wasn't hoping to hear. The upper rear ps control arm looks like someone took it off and used it to stir a 50 gallon drum of roofing tar. If the pinion falls in, can I plug the hole, drop the shaft, and lock the center diff for a while?

I would imagine the third has to come out or I risk catastrophic damage.

Having been through this twice, I would just pull the third and have a master kit standing by.

The pinion won't completely fall in. What I did was to set the e-brake, and then rotate the pinion so it would push itself out of the third to where I could replace the flange and nut.

But the tell tale sign of this problem is the oil on the link so I would really not try to just swap the seal.

There is a thread on mud covering my saga with this problem. I'll try and find it.

 

[Crashdix]

What parts are in master kit and what is the price at Toyota ( or if you have a better source). Need to do mine along with front and rear transfer case output bearings......

 

[landcruisertx]

I don't like to re-use the nut. The divots in it can distort the pinoin threads on re-applying it. You should be setting that nut by TORQUE value, not but old position. JOhn

do you know the nut part number?

 

[bicycleagent003]

Pinion flange cleaned and greased up before sliding it back on. The marks on both the flange and the 3rd member helped align the pinion flange back to it's original orientation. The middle photo shows the pinion nut before my last pull on the breaker bar, while viewing it from below it appeared like it needed to go a bit further. The last photo shows where the pinion nut ended up after my last pull, maybe ? 3/32 of an inch past where it had been staked originally. I could tell on that last pull that the nut was not going any further. So did I take up some slack that developed over the last 312,000 miles, or did I overtighten it?? I re-staked the pinion nut after the bottom photo was taken.

Edit: my recommendation would be to also mark the outside of your socket so it lines up with the pinion nut mark; that way as you tighten the socket you can watch the mark on the socket as the socket/pinion nut reaches the original position marked on the flange. Not the expert on this, but IMHO in this situation when you are just replacing the seal on an already built/used/preloaded pinion (and not using a beam type torque wrench) it is better to go a just a fraction (however small) past the original mark. As I understand how it all works, if you go short of the original mark you will end up with no preload at all on the pinion bearings as the crush sleeve has already been crushed. Any experts please correct me if that's in error.
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Hey Kernal, how is your front pinion seal holding up? I'm going to replace mine the same way you did this coming weekend. I'm planning to torque the nut to the same spot or very slightly past. Just curious how yours has been since you did this job. Any leaks or bearing whine or wear?
Thanks.