Tear deeper into transfer case?

[NOSAJ]

Built 2001 Lexus lx470 330,000 on the clock.

T case has been leaking out off front and rear seals for a while. Had the 3rd row and 2nd row seats out to do some camping, and pulling my 21’ wake boat. Not a terrible load but not light either. Close to lake was hearing a whine like a bearing right under where the tcase would be under the 2nd row seats. Maybe without the seats in was heard more and more pronounced. It was louder during acceleration and would fade on coasting. Anyway on the way home it seemed to get worse. My son took it out for school and complained about the truck shaking. So I took it out definitely whine and shaking now (still no seats in). So I was thinking time to do the seals and bearings on the front and rear seals and I pulled the case. The thing is I’m not seeing anything offensive. Fluid wasn’t excessively low. Magnet was pretty clean. The bearings seem tight and not even worn no play. I do have a slight and very slight play in the u joint on the rear shaft. But really I’ve seen a lot more slop on other vehicles. The front u joints are tight. The t case is out and on the bench and I’ve torn down the front and rear sections to get to the seals and bearings and not seeing anything there or on the limited view of inside the t case. Everything seems tight. So my question is do I tear this whole t case down and try and find something?? Or replace the leaking seals and bearings and u joints and see what happens?? Any advice appreciated!

Maybe the u joint is the issue??

Jason

 

[NOSAJ]

Btw the offending u joint is the rear and one down at the rear differential.

 

[badlander]

If your drained fluid looks clear then I'd leave it alone. If you see any grayish cloudy appearance, then I'd pull it apart because this indicates outer races spinning in the case and producing aluminum particles. The outer races will spin if the bearings have even light galling or pitting because this causes the rollers to grab rather than roll freely. This happened to me and the bearings were toast. It really suprised me as there were no symptoms other than the cloudyish fluid. I only pulled it out to regear it but I feel lucky that I did and dodged a bullet. Only had 195k miles at the time.

 

[2001LC]

Once TC opened up. At minimum, I'd keep going until issue found.

But I would have first:

Flushed the T-case. Inspecting old gear lube, by filtering inspecting any particles in filter. Which, I may have sent sample to BlackStone if any concern with look.

Finding old lube, normal.

I'd then added AT-205 and filled with fresh 75W-90.

***** I find clear breather, can resolve TC leaks.****
I'd also, have cleared the breather and it's hoses. I find the 98-02, have issues with clogged in long breather hose. We can also get, cross contamination. Due to A/T & TC breather hoses being "Y"' together at rear. This was correct, in 03-07.

I'd R&R the aft propeller shaft's spider found bad. These often, result in vibration and unusually sounds. We must work through issues as they're found, as part of diagnostics. Or we may chase endlessly.

I'd also make sure A/T fluid as it should be. Any concern with fluid, or if I've not personally previously having done a 12 qt. flush. I'd flush with 12qt Mobil 1 MV ATF (98-02), setting level, w/ATF at ~160F (98-02).

Then, if issue still present. I'd consider a TC rebuild. Once all else exhaustive inspected and rules out. Such as rear axle bearings.

 

[NOSAJ]

Thanks for the help @badlander and @2001LC

Will look at all listed

Thanks!

 

[NOSAJ]

Ok just now got back on this after a major home project. After really looking at the t-case it definitely had a mixture of ATF in it. The output shaft from the transmission had a little drip of red ATF on it too. I blew on the long breather hose going up to the top that @2001LC referred to and felt clogged at first then freed up and is free flowing now. Any recommendations? Change the AT fluid? Replace the seal at the back of transmission and the one on the t case side?

Thanks for any help,
Jason

 

[2001LC]

Clear breather(s) and hoses.
Flush all 12 qts of AT fluid.
Flush transfer case.
Clean and watch for leaks.

 

[NOSAJ]

Thanks @2001LC the breathers are clear except for the one at the y that goes to the transfer motor actuator. It is plugged solid. Is this one supposed to be free too? I haven’t cleared any breathers on the transmission yet.

Still don’t think I should replace the seal on the output shaft seal transmission and the one on the t case while I have the t case out?

 

[2001LC]

Thanks @2001LC the breathers are clear except for the one at the y that goes to the transfer motor actuator. It is plugged solid. Is this one supposed to be free too? I haven’t cleared any breathers on the transmission yet.

Still don’t think I should replace the seal on the output shaft seal transmission and the one on the t case while I have the t case out?

Picture?

 

[NOSAJ]

Seal in green is one of the 2 I was thinking about replacing while in there. The other seal is on the output shaft of transmission at the very back where t case bolts to transmission.

Blue breather is clear all the way up to the top and the section that goes into the t case. I split the y at the red section and it is plugged tight. It goes into the plastic housing for the actuator motor.

 

[2001LC]

Hoses, Y and fitting at cases, must be cleared at all times. The only check valve, is the one way breather valve at termination point.
Clearing breathers, lines, valves and flushing fluid is first step. Very often only steps needed.

Replace all the seals you like. But if breather(s) clogged. You'll build excessive pressure in case, and fluid will pass seals.

 

[NOSAJ]

Ok. Thanks for taking time to answer @2001LC I’ll look into clearing that one section marked in red and leaving the rest alone. It is really plugged. And I’ll read up on your AT flush thanks!

 

[NOSAJ]

So I ended up taking the actuator motor off the t case and was still not able to blow through it. I was able to get a section of guitar string through it and clear it out but was still difficult to get air through because it is so small. Anyway maybe this will help someone in the future