differential repair

P

Philip H Grant

Member
On the way back from a four-wheel-drive exploration of Utah's wilderness — from and to New York — the differential blew in Davenport Iowa (3 AM Sunday morning in the rain). It was towed to Smart Toyota. They said that the entire differential had to be replaced, and had to wait four days for the parts. I was charged $3100 (over the 2500 original estimate because brake lines had to be replaced and the parts were rusted so badly). Finally got out of there the following Saturday — and I started hearing a noise in Ohio.

I looked underneath and there was fluid all over the differential and spare tire. Virtually nothing in the differential itself. I put in 3 quarts of 5W-30 and stopped at the next pilot truck stop and grabbed all their gear oil. I then drove for an hour — at 50 miles an hour — and then added a quart or more. 8 quarts later my wife and I got home.

Discovered a leak in the differential about 6 inches above the filler hole. When it was just parked it didn't leak. When I jacked up the rear end — tires off the floor — and ran it through the gears it leaked. I fixed the leak with epoxy.

I can hear the noise in the garage when I run into the gears with the tires off the floor: a whine or howl at certain torques. I tried 85W- 140 gear oil but it didn't help.

I told Smart Toyota service managers the whole story. I have an appointment with Dorschel Toyota in Rochester New York (50 miles north of me) June 1 at 10 AM. I didn't tell them about the leak — yet — because I'm afraid they'll say that that voids the new part warranty. But they started saying things like it might be the carrier bearing or the wheel bearing, and I know it's not. I'm afraid they'll do work it doesn't need and still not fix the problem. (I normally do on my own repair work because every repair I've ever has been screwed up, but differentials are beyond me..) the new differential only has a one year warranty and here at home I only drive about 1500 miles a year (when not going on long trips). I'm afraid they might say also to just wait and see if it gets worse. But it has been getting worse since I first heard it in Ohio. I'm afraid they might stonewall until the year is up.

Any advice? Should I tell the dealership about the leak? I'm afraid they'll say that is Smart Toyota's problem, and not cover the repair.

The frame was replaced a year and a half ago and mechanically otherwise it's still in good shape. It has a homemade camper top which is the devil to transfer to another vehicle. I wanted to keep this until self driving trucks arrive. 135,000 miles.
 
By entire differential did they mean complete real axle assembly? If so that should mean everything internal should be new, not reused from youre old one. You may have to get toyota headquarters involved to get youre local toyota dealer to cover work done by another dealer. If they say that Smart Toyota has to do the work id contact a lawyer and see if it would be possible to have Smart Toyota pick up the tab on transportation from youre location to them and back to you once it's repaired, hopefully correctly this time.
 
I took it into Dorschel Toyota in Rochester New York yesterday. Before taking it in I discovered there was another leak where the drive shaft enters the housing — Smart Toyota seems to have left off the seal! I ended up telling Dorschel the whole story about the leaks. They are contacting Toyota headquarters to see if it will be covered under the new parts warranty (not sure if they will tell them about the leaks; I think not); they think it's likely that it will be covered. I'll know by next week. If not, Smart Toyota SHOULD pay for it. But how I will get them to do it I have no idea. This Tacoma is my only vehicle so transporting it back 1000 miles to Iowa is rather impractical.

I thought they would, but they did not replace the outer housing of the differential. If they had it would've removed the part that had rusted through. Evidently the whole housing is virtually never replaced.

Dorschel also told me Smart Toyota charged me $150 an hour for labor, versus $110 for them — and they thought they were expensive!

Moral of the story: If you have an older vehicle, make sure the differential isn't rusting through! If it had blown on the remote four-wheel-drive roads we were on the towing easily could've been $2000 or more!

I normally do my own repair work — because every single repair I've ever had done, dealership or not, has been screwed up. I had the frame replaced year and a half ago — due to the rust recall. I thought it had been done okay, but checking over the truck before our trip I noticed the four bolts connecting the four-wheel-drive driveshaft to its differential were about a half inch loose! They had rusted in place, but easily could've snapped off under high torque. I had been noticing sort of a clunk in four-wheel-drive from time to time. Found out why! I make plenty of repair screw ups myself, but at least I'm not paying someone else.
 
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the repair has been completed. They wanted to sell me a new housing for only $2000 more. The mechanic took pictures of three spots he said it was still leaking. I told them I thought it was just excess oil left over from the the previous leak that Smart Toyota made by not installing the seal around the driveshaft.

So I drove it home last Friday free of charge. The differential itself sounded fine. Checked for leaks: nothing on the housing was leaking, as I suspected would be the case. But there was a leak around one of the bolts holding the cone shaped housing where the driveshaft enters to the main housing. Actually, it was coming out the bolthole and dripping off the end of the bolt on the lower left side. Obviously the gasket or gasket sealer wasn't installed properly. I will probably just try to take the nut off and seal it myself. But I'll have to keep an eye on the whole thing and if necessary taken back to Toyota.

As I wrote above, I've never had a repair done properly by anyone. But replacing the differential would've been beyond my abilities.

I don't know if Smart Toyota contributed or not.
 
I would give Toyota zero slack on that drip. When I bought my 2018 off road I had rear axle seeping from the carrier gasket and around the carrier bolts. I installed a vent in the rear axle and in 15,000 miles there are no leaks or any weeping at all. The 'vent' that Toyota puts in the rear axle keeps the axle under positive pressure. When the axle gets hot, the pressure rises, the oil thins, and you have leaks. I ran my vent hose into the plastic gas filler housing . Zero problems.
 
thanks for the tip but yesterday I cleaned off all the oil with paint thinner — the truck has just been sitting in the garage for the past six days — and this morning I can see fresh oil has seeped down from the gasket even though it hasn't been driven. So I'm not sure why your idea would help.

I'm debating whether to just live with it. I'm so disgusted with repair work. The "technician", a.k.a. grease monkey said I needed a new housing for $2000, which wasn't true, and then when he repaired it he made a new leak! If I take it back maybe he'll be pissed off about that and make some other screwup. intentionally. Like loosen my transmission drain plug a little bit. Screwup the clutch when he test drives it. I know this sounds paranoid, but as Woody Allen said, "just because I'm paranoid doesn't mean someone's not trying to kill me."

I even start to think technicians — a.k.a. grease monkeys — are trained to screwup to encourage people to buy a new vehicle.
 
When I removed the vent from my rear axle the truck was overnight cold and parked inside. There was enough pressure in the rear axle housing to pop the vent plug out when it reached it's last thread.
 
Okay, but before I cleaned the oil off I had opened the fill hole to check the level so any pressure should of been released there if there was any. But I did see online that others are doing what you did just so that if you drive through a stream water wouldn't get sucked into the differential. So I may do it just for that reason.

I notified Toyota of the problem and asked how long a repair would take. But I'll probably drive it more to see how much is actually leaking before bothering to take it in. It's my only vehicle and we live 55 miles south of the dealership — Rochester New York — where we only go in every three weeks for shopping, so it's a real hassle to take it in.
 
As you said, when you removed the fill plug you released any pressure. That would remain so until you drove the truck again and the rear axle became warm. If you have more than a weep, just a stain from the gear oil, then you have a problem caused by whoever did the repair.
 
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I'm not sure what the Toyota gasket looks like, but FelPro makes their carrier gaskets (the one on your truck that leaks) that are imprinted with a bead of silicone around the perimeter and around the bolt holes. Best gaskets out there.

Most likely the rear housing has a dig in the mating surface causing a leak, or a similar dig in the carrier unit causing the leak. I'm like you, I prefer to do my own work. Best of luck to you.
 
actually, the one thing Smart Toyota did right was I could see there was a bead of permatex gold all the way around— maybe they didn't have a gasket. But it didn't leak there! What you think: is is it worthwhile to, without disassembling it, just fill in the groove between the mating surfaces with permatex gold? Might that stop the leak? Same thing with the two bolt holes.
 
It can't hurt, but I doubt that it will cure the leak. There should be a gasket between the carrier and the housing.
 
I just replaced the rear wheel left bearing because it was leaking grease onto the brake pads. (Big project as I had to cut the bearing retainer and the bearing off with a metal cutting blade on my drill. Then take it to a shop to have the new bearing pressed in.) I looked in the differential housing — and it was full of particles of rust! The housing itself was like new. I drained the oil — it was orange from rust! Note that I had put in about 9 quarts in the whole process of driving back once I discovered it was leaking so the tiny bit of rust where it had rusted through was negligible and should have been long gone)

But in the main part of the differential — there are little barriers that keep too much oil from coming down the actual shaft where the rust particles were — there were no rust particles. Presumably they had been all ground up.

So the Toyota dealership — and Toyota itself, since they had to order the part and wait for a week — gave me an extremely rusty differential that somehow had been sitting out in the rain for months or 15 years? They figured I'd never notice.

I put it back together. Put one round of gear oil through it to flush out all the rust. Then put in 3 quarts of synthetic. I also added this for luck

.https://boostperformanceproducts.co.../15-cleanboost-emt-engine-metal-treatment-8oz

I've only driven about 500 miles since the repair (I don't drive very much these days, except on trips out West). Most of the noise that was the problem before they repaired it the second time is gone. But there's a little noise on acceleration if I give it enough torque at roughly 3000 RPM in first and second. Anybody know if this is normal or if it will last me for another hundred thousand miles? Hundred and 35 miles on the truck at the moment.

I'm damned if I ever will buy another Toyota!
 
I should mention that the leak has virtually sealed itself. The noise in first gear is a little buzz around 2800 RPM. In second gear it's about 3200 RPM. And I have no idea if it was there all along, or when the truck was new.
 
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this read was quite the difficult ordeal you had OP
and I don't mean truckin' through that Davenport at that hour of the morning :eek:

had you ever checked the condition of that vent valve thing screwed into the axle housing that it wasn't all chocked and clogged up not allowing any pressure to escape the enclosure
i did not know it was a thing either until somewhat recently
 
When i had a jeep cj back in the day i blew the rear differential out 4 wheeling. I was able to drive it home using just the front differential while in the 4wd mode. When i took the rear end apart, not much was any good. Nothing but blown pinion, and ring gears, plus stripped spider gears. I was able to buy all the individual parts.
 
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