2005 Toyota Tacoma Rear Axle rusted though and leaking, Fix or Trade?

My V6 4x4 Tacoma Double cab has 77,000 miles. I live in the Adirondack Mountains of NY, a high salt area with the closest Toyota dealers over an hour away.

I noticed the breaks were going and some oil leaking from the rear axle ‘pumpkin’. Took it to my local mechanic figuring the calipers in the front were seized again (replaced everything in the front breaks twice now), and really didn’t know why the pumpkin was leaking.

Mechanic said I have 2 major issues. 1st, the vent on the rear differential was plugged causing pressure to build up and pushed out the seals on each end of the axle coating the drum breaks with gear oil and ruining them. He also found that the pumpkin was rusted out so bad that a pin hole had formed and was leaking gear oil also. He unplugged the vent and sent it home with me. He said fixing the rear axle was way beyond his tooling and that I should ‘find a new home’ for it.

I have no idea what to do now. Not even sure how to go about fixing it. Mechanic said everything is sealed up back there, and fixing the pin hole would be very difficult and it might be easier to try and find a used rear axle for it. He suggested not fixing the rear breaks until the axle itself was fixed so it doesn’t happen again. He said it was possible that the rear seals would not leak again with the vent cleared, but wasn’t sure.

This is my 3rd Toyota truck and maybe my last. Should I trade or fix? If I trade, what do I need to tell the dealer? I’ve already taken a look at the local used car places and said there was a break problem, and was offered 1350-ish for trade. OOPS Forgot a 0, that should have read 13500

Thanks for reading!


Of course a dealer will offer you squat as a trade in

If $1350 is all you’d be getting as a trade-in, you’d be better off finding an axle housing.

FWIW I believe your axle seals will be fine for awhile

Transmissions sometimes have seepage from the housing, due to case porosity. And they are SOMETIMES fixed successfully with epoxy.

Is your pumpkin so bad that you’re past the point of an epoxy repair?

BTW is the rest of the Truck (the frame, suspension, steering, etc.) also severely rusted?

db4690, thx for the reply. I’d say the frame/suspension/steering is rusted, but not sure if its severely. On my last tacoma, a 94, I had a leak on the pumpkin, and I fixed it for a very short time using jb weld (sold the truck a few months later to get this truck with the 4 doors).

Here is the pumpkin:

And here are 2 pics of the frame:

taken at a strange angle, sorry, passenger side, behind front wheel, looking front:

Sure, this truck isn’t mint by any means, but this is something you could fix yourself. Is the leak from around the fill plug or down lower in the housing? I can see fluid that looks like it might have been spilled during filling. If the fill plug isn’t tight, I would remove it, clean the threads well with carburetor cleaner. Try and clean the hole in the housing as well as possible. Goo of the threads of the fill plug with Ultra Black RTV sealant and tighten. Let sit overnight and you should be good. If lower in the housing, DRAIN all the fluid from the axle. CLEAN off the rust around the hole with a wire brush and rough up the area. Find a thin piece of metal and shape it to the contours of the area around the hole. Rough up the side that mates to the housing. Apply JB weld and let sit for a couple days. I did this on an oil pan once and it continues to hold many years and tens of thousands of miles later. It is SUPER IMPORTANT to have the surfaces VERY CLEAN, otherwise this patch won’t hold long. Use carb cleaner and brake parts cleaner once you have the metal prepped to make sure all oil and dirt is removed.

I was hoping the diff had a plate with a flange bolted to the rest of the housing as that would have been easily replaced. Most I have worked on are like this but I don’t mess with many Toyotas.

As for the frame and wheel well rust, wire brush this, pressure wash it with water, let it dry outside for a nice dry day, apply Rustoleum Rusty Metal Primer, and then follow with several coats of their PROFESSIONAL undercoating. It costs more but seems to work better. Most home improvement stores have this. Wal Mart might but I think they only have the low grade kind.

@cwatkin OP’s rust looks as bad as earlier Tacomas that were bought back for rusting through

The frame is already on the downslope

Attempting a “fix” of the leaky pumpkin is worth a shot, as long as the repair is cheap.

But nothing is going to fix that frame. The process is already well underway

Fix it for pitys sake ,BTW looks like water running out of the drain plug in the picture,Every chance you get you should wash the salt off if possible,you do have a little time,for most of the corrison occurs after it warms up a bit,clean the rust up as good as you can and prime and paint-then give a dose of diesel fuel and oil every whipstitch.Toyota are you listening? can you give us a little more Nickle or something in chassis materials to increase the rust resistance,you are damaging your reputation on otherwise fine vehicles-Kevin

Replace real axle housing with one from a junk yard. There will be a gazillion of them. Scape frame down as best you can and spray ( motor or linseed) oil from a garden sprayer inside frame as best you can. Paint red grease with a foam brush on outside and spray areas that are hard to reach. If you do this every over year ANY places you can reach will not rust anymore. If you don’t, kiss the truck goodbye… Painting or any undercoating material which will enhance rusting, at this stage imo, is a waste of time. I guarantee, that if you do this a couple of times, the life expectancy will increase many times over. Spray oil under truck bed, fenders, in body panel drain holes and doors too.

It’s messy, you need to spread news papers till oil runs out , but it works and any one who can work a garden sprayer can do it. If you worry about the environment where you are, use red grease and linseed oil.


With all due respect, anyone who says that rust once stated can’t be stopped, is wrong.It takes a little work, but it can be done… Rust needs O2 and oil or grease prevents rust but must be renewed everyso often before it washes away…nothing else works as well. Ask the military and old farmers.

This truck – at 70k miles – still looks very serviceable to me. Ask your mechanic for a recommendation of an inde mechanic who has the tooling to work on differentials. It looks to me like it can be repaired at least well enough that it will work fine, but you might have to check and top off the fluid level once in a while is all. A little leak from a differential isn’t that unusual. Plus it appears the leak is from the threads on the plug not sealing, which is easily rectified by the RTV method posted by @cwatkin above. I’ve fixed a similar problem just wrapping the plug threads w/a layer of teflon tape like plumbers use. If you see signs of leakage through porous metal in the housing, Google that problem. I expect there are simple methods to minimize the flow rate of the leak to the point where it would be acceptable (for a used truck that is).

If the differential seals need replacement, even that isn’t that big of a job for an inde mechanic with the right tooling.

Do you have one of those do-it-yourself car washes in your area where you put some quarters in the meter and they provide a pressurized wand that spray water at a high force? Those work very well at removing salt from the underframe and wheel wells. During the winter when I lived in snowly Colorado I used one of those car washes every week to remove road salt from under my Ford truck, and the truck (early 70’s) – a little the worse for wear – is still and on the road.

On the other hand, if you are looking for an excuse to buy a new truck, I think we can agree you have one. Your truck isn’t in as good condition as would be a new truck. Some teenager in town would probably love to buy it from you. And you’d contribute to the economy and provide jobs by buying a new truck. It’s a compromise.

Thanks for the suggestions! I might try fixing it myself now with this support. I don’t want to buy another vehicle at all, just worried how deep this could get. I kind of like the idea of JB-Welding a plate to the rear diff. What metal would work well? Not steel I’m sure… I’ve got quite a bit of aluminum kicking around.

Anyone have experience with the rear seals on this model? My mechanic said that he didn’t think they could be replaced without taking the whole thing apart (including bearings). He’s a little old fashioned and longs for the good old days, so it might not be too bad.

As far as the rust, I have been a little lax on the rust prevention. I bought the rust treatment from the dealer, and do wash it a few times every winter…I know I should do it more, but what a pain. I really like the idea of the lanion oil and have a friend who also swears by it.

Thanks again,

I forgot a 0 on the first post, I was offered 13500 on trade, not 1350…oops. Still leaning toward fixing it

I always found it was a bigger pain trying to fix a rust out fender or frame, as well as pay for it, then put a set of coveralls on, fill the sprayer with linseed oil or the like, crawl under and do the job, once every other year. It takes only about twenty minutes after a little experience. Beside, you will become more informed with your undercarriage and much more likely to inspect it regularly yourself long before things like this get out of hand. Get your friend to guide you through.

Btw, rust treatments from dealers that not factory installed, can accelerate rust…they are totally useless in general.
Guess we are not telling you anything you don’t already know looking at your truck.

Anyone have the rear axle seals replaced on the 05 tacoma yet? Is it as big a job as I hear?

Dont patch steel with aluminum,it will create a set of corrosion problems all its own,kinda like the anode on a battery,particulary in the prescence of salt and moisture,even though the aluminum will corrode much faster,just doesnt sound like a good idea-do the “Dag” my former bosses noted years back that a fuel tank on the back,with attendent diesel fuel spills stopped the sheetmetal from rusting out-Kevin

Yes, I used aluminum sheet to patch my oil pan as the oil pan is cast aluminum. You will have different expansion characteristics as well as different metals expand and contract at different rates with changes in temperature. I would just use ordinary steel and prime it and undercoat it once you are done. Yes, aluminum would essentially “sacrifice” itself and the rusting of the steel would actually slow down but I would just use steel and be done with it.

My oil pan is also integral to the engine so the engine would have to be removed to replace it. I had obtained a good junkyard unit but didn’t want to spend the time replacing it once I figured out what it involved.

As for the frame, you CAN essentially stop the rust or slow its rate to that of a basically new car. If your frame is a box tube, you can fill it with Eastwoods Internal Frame Coating. The stuff is expensive but many swear by it. I would try to pressure wash all the crap out of it you can and let it dry really well before doing anything. Then treat the outside by wire brushing as much rust as you can and then pressure wash and let dry. Actually, I would do the cleaning part as one step and do the inside and outside next. Spray the outside with Rust Oleum rusty metal primer and then their pro undercoating. Trust me. I drive old beaters and several of these types of repairs still look as good as the day I did them. The rust on your truck isn’t yet structural so why not keep it that way?

The big problem with these undercoatings is four fold. First, the surface must be rust free. If any areas are not completely free of rust and the undercoating is applied with any access to moisture, the moisture is held in place, not allowed to dry and accelerates rust…remember Ziebart ? Nothing has changed. Secondly, this stuff does not migrate and you must directly apply the area, rust free with any coating. It will not run and Follow the path of any trapped moisture which itself runs into weld crevasses and low areas with no drain holes. Thirdly, it’s expensive. Once you apply this stuff, just like other petro based substances, it can harden, make things worse and last and most importantly, CLOG INPORTANT DRAIN HOLES which further exacerbates the problems.

Oil, on the other hand, does not need rust removal, except for minimal scraping, it migrates and follows where ever water naturally flows, it’s cheap, and it does not clog drain holes and because it will not wash away in areas without direct watere contact, will last a long time, as much as several years while our after maket undercoating is promoting rust on several levels. Oh, did I mention it’s a much easier clean up. Also, continued rust can be hidden until that good looking frame collapses under weight and the worst could happen. We should never cover rust with cosmetic fixes so you can’t follow it’s progress; it isn’t safe…

Either use fresh motor oil if you are fastidious about controlling the flow or linseed oil if not. It’s biodegradable. Lastly…oil ( red grease on areas you can paint) is completely idiot proof. I can do it, any one can. There is no such thing as a one time fix it…if there were, it would have been done at the factory.