so today i replace the u joints on my rear drive shaft..also did the pinion seal because it was leaking..when i drained the oil it was like chocolate milk..figured it was in there for atleast 5 years so i put new gl 75-90 fluid in it..also did an oil change..after spraying some degreaser on the under carriage let it all dry up..took it for a test drive..still vibrates a little but the worst is..there is still fluid coming out from behind the u joint..near the pinion seal..and its not milky its the right color...
any ideas on whats next or what else i should check..im kinda lost on this one..
once this is done..truck is up for sale..

 

anything????

 

maybe the seal got messed up when ya put it in?

 

well the seal that was in there was a thicker rubber seal..then new one is kinda of metal and the width is shorter..but the diameter is the same size..i did read a few posts..i need to check the breather...just got to find it

 

You shouldn't just "replace" the pinion seal. You need to tear the differential apart and rebuilt it. The crush sleave on the pinions shaft is a ONE time use disposable item (unless you are using a Solid Spacer) and needs the proper torque. Either way, solid spacer or factory crush sleave, the pinion nut needs to be torqued properly to work correctly. If not done properly, it can and likely will destroy your gears. Is there excessive "play" backlash in the differential? And can you feel the pinion flange move forward and backward (in and out) of the 3rd member?

 

there is no play in the pinion itself...how big of a job is rebuilding the diff?? now im talking about the pinion seal that is on the back of the transfer case..just to make sure we talking about the same thing..i was told to put some rtv on it

 

i just put permatex ultra grey sillicone type glue on it and it hasnt leaked since, its been about a year. the stuff can be found at any automotive parts shop

 

okay so i pulled it off again..and since it was a newer seal and was smaller in diameter..i seated it all the way and no leak..YAY ME..thnx for the advice guys..

 

okay so i spoke too soon..there is still a very small leak now..i think im just going to RTV it and call it a day

 

Hey make sure that your diff breather isnt plugged.
when mines plugged it sends oil out the pinion seal cuz of the case pressure

 

i see the breather on the rear diff..its not clogged up...i dont see the breather on the transfer case or 3rd member...where is it located???

 

Generally diff. = 3rd member, at least on a Toyota. Breather atop axle housing vents the whole axle and differential volume.

T-case ventilation is typically though the shifter, no separate breather.

 

not true i run with no crush sleeves and tacked threads instead of staking, once the bearings are broken in and still no play. ive got 2 years of hard driving and wheeling outta my rear end with no crush sleeve, it serves its purpose in setting bearing preload but can be done without if your nut is tacked and cannot back off

 

so if thats the diff..then the part in the back is called the rear end ..and front end haha..
well since the breather is thru the shifter..then if there is no clog then there is something else wrong to make the pinion seal leak..

 

The sealing surface on the pinion could be damaged or worn to the point that the seal can no longer effectively seal. But what I have found is that with a new seal the lip needs some time to round/flatten itself down a bit to provide a better seal in some instances. With a new seal the lip of the seal is sharply pointed and has less surface area to create a good seal. So give it some time and it may well "fix" itself.

Your breathers should be in the same general area as these.

That's not only ridiculous, it's not true either. The FSM states that a crush sleeve can be re-used or re-torqued so long as when doing so the recommended drive pinion pre-load is not exceeded during the process. The procedure calls for tightening the pinion nut gradually untill the recommended drive pinion pre-load is achieved. The process can be repeated as necessary providing that the pinion nut torque does not exceed 253 ft. lbs. before the correct drive pinion pre-load of is reached.
http://personal.utulsa.edu/~nathan-b...35differen.pdf

 

perfect..thats just what i needed to see..i did not replace the crush sleeve..just torqued it down..gonna check the breather then throw some RTV on it and should be fine..thnx again guys

 

Hello Myron, two questions I have for you. First I have not read any previous post so forgive me if I ask a question that might have already been asked. The vibration was it there before you changed the u-joints? Second, toyota joints are some of the most finicky. Make sure you do not have any burrs on the metal when installing the new u-joints or they will cause a vibration. Also when you replaced them did you mark the flanges before removing them from the driveshaft. This will cause a phasing vibration as well. Sealing surface may be worn, this is correct, however, whenever you install a seal of any sort look to make sure the spring inside has not come off of the rubber ring it seats into. Put a little bearing grease inside there to ensure it doesn't come off when tapping it into place. Lastly is the oil coming from the seal or up through the splines of the pinion gear? I know this is a little more than a quick reply but hope it is helpful information.

 

hey,
the vibrations were really bad..till the slip yoke of the driveshaft broke off leaving the u joints still attached to the flange of the 3rd member.
unfortunately i did not mark the flanges before i removed the drive shaft to put new u joints. im actually going to get the driveshaft balanced next week.
only after doing some research on why i still had vibrations did i see that u actually had to mark the flanges.

with the pinion seal..the leak is coming up through the splines and over the seal and then collects just under the flange house in that little cavity.
I pulled the flanged of put RTV sealant around the seal and a little on the flange house..i did this about 3 hours ago and there is no sign of a leak..

thanks again for the information, i also think the vibrations are coming from the tires not been balanced, going tomorrow to check that out.

 

A tip I learned from Marlin was to apply some RTV to the splines before putting the flange and nut on. This helps prevent gear oil leaking out the splines and around the nut and washer. Works on the pinion and t-case flanges.

 

Myron,

Just to Clarify, Are replacing the "Pinion Seal" on the REAR Axle? Or the Transfer case OUTPUT SHAFT seal on the back of the Transfer case?? Two VERY Different Parts!

Or Both?