vermontoyota

The last time my truck was on a lift (the only time it was on a lift since I've owned it) - for some reason the tech broke the rear diff breather.

When I picked it up from the timing chain job he mentioned this, I asked him why and he said he thought maybe it was plugged so he tried to free it up and it broke....

Anyway, prior to this the seals seemed tight. I had changed it to Amsoil Severe Gear about 12 months earlier and none lever eaked out.

I noticed gear lube starting to collect on the pumpkin after this. I figured pressure was building up and that I had better change it. Picked up the part for $2 or whatever they are from Toyota and changed it for a shiny one.

4 months later, more and more gear lube is finding its way out-faster than before, giving my bed a nice undercoat but not making me feel good. I opened the fill plug and "Shhhhhhhhh" - clearly pressure had built up. I filled it back up (about 1/2 quart +) and checked the vent. I could not blow through it - clearly it was not working after only a couple months in service. I got the dealership to give me another one and I replaced it.

here's the question: did lack of ventilation cause the seal where the drive shaft enters the differential (via U joint I assume), to fail? Can this be fixed or replaced? If not properly vented should that seal now do its job (ie pressure won't build up?) Could that vent have been blocked by metal fragments, indicating severe wear?

Worst comes to worse I'll have an excuse to put in 4.56 gears, but I'd like to not blow my differential on accident. It also stinks like gear lube everywhere I go.

snobdds

The rear pinion seal does wear out over time. It could be the pressure has nowhere to go but through that seal. Just replace the seal, I think it's $20 bucks from the dealer. While your at it, replace the breather too.

I did this a month ago and it only took me about an hour. Not hard at all...

dropzone

iTrader: (6)

What kind of lift are they using that would cause the diff breather to break? Having a hard time figuring that one out but oh well.

But if the vent is plugged, the pressure has to go somewhere, one of three places-one of the two axle seals or the pinion seal-where the u joint go

Fink

I renamed your thread - if you have to censor the thread title I would just pick a different one.

Fink

sb5walker

Be aware that the stock breather allows pressure out but not in. When the diff gets hot, air expands and is vented, then when it cools a vacuum is created but the breather (if it's working right) seals and doesn't allow air to be drawn in. So that SSSSSSSSSS can be air being drawn in, not escaping.

vermontoyota

Okay I'll pick one up as its clear that is where it's coming from.

The lift didn't break it - the tech thought it may not have been venting so he tried to free it up and broke it. I just was implying that it was in a shop, not that being on a lift had anything to do with it.

Sorry about the title. Point taken.

Good to know- Maybe next time I crack it I'll put some soapy water around the fill plug and see if I can tell if its going in or out. Out and I'll know the breather is not working (again) and if its going In I'll assume the breather is working.

Thanks for the help

Keith B.

My suggestion: Replace the stock breather with the later one made for the Tacoma--and extend the breather "valve" on a hose while you're at it. Do search for 'Diff breather extension'. The Taco breather allows flow both ways with minor resistance. Test it yourself by blowing through it in both directions. Toyota had good designers, but I personally cannot construct or invent a scenario where it'd be a good idea to have a stock, 'one-way' valve, especially if the two-way valve is extended and not likely to be submerged in water, etc.

vermontoyota

I took a peak at the online FSM and it looks like to replace that pinion seal on the truck you need two different SST's. Anyone done this without?

For things I plan on doing often (i.e. oil changes on my GF's 2010 corolla) its clearly worth forking out the money. But I hope to not have to change this pinion seal again. If you need them to do it right, and they're expensive it may be more economic to have a dealer do it

Also - when I added gear oil yesterday it HISSED again - on its third diff vent in recent history. I can't beleive that's the shound of air going IN the diff. Getting hot, I dont beleive negative pressure could build up. I mean I guess if its leaking fluid out that seal and the leak is slight enough not to let air in then a vacuum could be created by loss of fluid not being replaced - but I'm thinking of simply doing the extended beather mod first, and hoping the leak stops. At this point two quarts at least have leaked and been replaced, so my hopes for the seal still being good when properly vented arn't that high.

Anyway- anyone done the seal without those SST's??

snobdds

I used no SST's when I replaced my seal. A little tip on replacing the seal...put the seal in the freezer for a few hours prior to replacing it. Also get a 2x4 and cut a round hole in it about 1 - 1.5" wide. Then put the cold new seal in and tap into place with the 2x4. The hole will fit over the pinion shaft. Works slick as snot!!

Just remember to count how many threads are exposed on the nut to get the proper torque on the nut. Also note where the "stacked" part of the nut should be. I also had to use a inpact gun to get the nut off of the pinion shaft. Mine was on there pretty tight.