I’ve replaced a number of pinion shaft seals on trucks about this one’s age. The seals only lasts so long and they start weeping. It’s not too hard to replace. Most of mine have been Chevy’s and they use a crush sleeve. That’s the hardest part of the repair IMO, getting that sleeve to compress the right amount. By hand it is very difficult. An air gun makes it a lot easier…
I have torque wrench. Can you point me to instructions for this? I’ll look, but if you know something that’d be nice. I don’t have a lift so I’d do it on my back.
I think rtv on the outside is just going to weather / wash off. I’ll have to google a pic of a 1998 Tacoma (I believe you said?) rear differential to understand what you’re explaining on how that thing is assembled.
'87 Toyota pickup, 22R, carbureted. For some reason the choice of make & model in these threads doesn’t work for me. I have the Chilton’s and the Haynes.
As mentioned, they can be real bears to change by hand (pinion seals). Removing the pinion nut is tough. I was unable to remove one on my old CJ5 with an impact. Not enough pressure from the compressor, I guess. So I had a shop do it.
I wouldn’t worry with doing that until I was certain it was leaking there, although it’s not uncommon at all.
This is from a 1992. Is yours similar?
image|666x500
There should be a gasket between the carrier (the part with pinion, yoke, etc) and the axle housing (the part that the carrier bolts in/onto). Someone correct me if my terminology is wrong. I believe you’d have to remove the axle shafts in order to seperate those two parts, which could get a little involved. Again, someone correct me if I’m wrong. I’m no expert here, and tend to leave transmissions and differentials alone other than very basic stuff.
1 Like
There it is. Looks a lot like a Ford 9”, for you hot rodders.
Is it that cylinder on the top, a bit to the driver’s side of center, about an inch tall, about ½ inch diameter, a sheet metal cap that moves a bit up and down?
Is that permanent damage?
I drenched it in mineral spirits and scrubbed it with paper towels; it was clean. I couldn’t blow anything out of it.
That looks like it, from the bottom. Is the thing that sticks out on top the vent?
After a closer look today I see the forward side the bolts on the bottom half are oily as are the vanes beneath each. It seems that it leaked out those bolt holes. There’s no new leaking and the drain bolt is as clean and dry, but the leak is really slow.
I’ll have to get a new 24mm socket.
The Chilton’s and the Haynes tell me to check the level by putting my finger in the fill hole and feeling if the oil is within 5mm of the bottom of the hole - really? Who does that? For a finger, it’s a small hole.
It looks like the vent is underneath the axle in this photo. I’m assuming the axle has the top facing down in the photo. But yes, the vent would come out the top of the axle. I think you can see the end of it in the photo. Should be a little plastic cap on the end of a rubber hose. The other end of the hose attaches to the differential somewhere near the top, but can’t see exactly where in the photo.
As for checking the level, 5 mm from the bottom of the hole isn’t much. If it’s low or you can’t get your finger in the hole (no jokes, please), just add gear oil until it runs out the hole. A few ounces overfilled won’t hurt, especially since it seeps a bit.
Ok, jokes are permitted.
It’s a cylinder of solid metal with a sheet metal cap, no rubber hose, no plastic cap. I don’t see those.
Really! I can’t even get a finger in and crooked enough to do this, so why recommend it? The owner’s manual says to fill it to overflowing, what I did.
You can use a 15/16" socket.
Ah, Toyota does the vent a little different apparently.
But the fill and check methods appear universal. Cause er’body wants to stick their finger in a hole.
That’s what I remember from my 1979 Toyota 4X4. I removed it and put in a threaded barb, then ran hose from the barb to a much higher place on the truck.
Seals leaking, drain plug, or plugged vent. More common though is that sometimes the differential metal casing is a little porous and gear oil weeps through a little. Unless the gear oil is low, whatever the cause, when I see it on my truck’s differentials, I just ignore it. When I first bought my truck it was one year old and had a noticeable leak from the rear differential. Definite puddles of gear oil underneath the truck. I had to replace one of the seals to fix that one. Don’t recall which seal it was, but It wasn’t a very difficult job as I recall. The biggest problem I think was all the oil drained out in the process, which made the job a little messy.
Differentials leak for various reasons but porous metal housings is not a common problem in my experience.
When you remove the fill plug and check the level you may find that the loss is insignificant.
Why?
This is such an astonishing claim that I must not understand it.
Hmmm… What is a differential? I think of mine as that ‘pumpkin’ (@Scrapyard_John 's word), the only seal is where the 2 parts go together, around the circumference. The seal where it attaches to the power shaft, the pinion seal?, requires separating the 2 to maintain, which looks difficult to me, especially lying on my back.
I’d drain the differential first.
The pinion seal (the front, where the driveshaft enters), just requires removal of the driveshaft and and yoke (part that connects drive shaft and differential). There will be a seal behind the yoke, on the snout of the differential. The only issue there, is the nut that holds the yoke on (on most differentials) is torqued to 4 billion foot lbs (ok, not really, but it’s tight).
The other seal on your differential, where the differential bolts into the axle housing, requires removal of the axle shafts to seperate the differential from the housing in order to get to the gasket, I think. I’m not 100% sure that the axle shafts have to be removed. It does on a lot of applications. The Toyota axle appears to be built similar to a Ford 9” axle, which was a common swap in the hot rod community. I was hoping someone who had more knowledge than me would chime in as to whether the axle shafts had to be removed (or at least slid outwards) in order to seperate the differential from the housing.
I’d recommend starting with the easiest items. Clean it up and make sure oil isn’t coming from the drain plug, fill plug, or vent/vent tube. Then proceed from there, if you wish. Although, if the truck is driven very little and it’s a very small leak…I might be inclined to leave it, depending on your skills, tools, and work area.
It’s a mod I learned from some off-roading magazine. The little spring-loaded valve on the top of the pumpkin can release pressure from inside pumpkin. The heat of operation raises the temp therefore pressure of the air inside. If you cool the pumpkin quickly, like dip it into a lake, the air inside contracts. If the valve does not seal perfectly, water can be drawn in. That’s not good for the long-term health of the gears and bearings.
Google 'porous axle casing ', I expect you’ll see some links.