Hi Mark

I recently found this sight. I have the same problem with rear differential housing rust out on my 2001 4 runner. I went to the goverment official complaint site to log in a complaint. The site says it will review complaint and if they see a trend will have the manufacturer look into it/fix it. The site is down for repairs until tomorrow. i plan on filing on official complaint for this problem. There is already one there from 2008. Please go to the site and log in an official complaint as well. If we all do so, maybe Toyota will see there is a trend and will do something to help us out.
The site is www.nhtsa.gov It is the official site of the Office of Defects Investigations. A contact phone # if you want it is 888-327-4236. Please file an official complaint if you have not already done so.

Good luck. Hopefully, we will see some results.
smilesbd

 

Everyone,
Bad news from Toyota. The will NOT help with any goodwill adjustments of any sort on 4Runner differential rust. I must say that I am very disturbed by this rejection. The only recourse is thru the NHTSA Complaint process. If you have this problem, notify the NHTSA. There are 2 complaints on record now.

 

Hi,
I also came across this thread. I too have a 4-runner with the rear diff rusting out with a pin hole leak dripping oil. The location of the rust hole is on the bottom part of the pumpkin. The dealer tried to check the oil level in the differential but couldn't get the fill screw out because it was rusted-in and couldn't be moved. When they tried tapping the fill screw it with a chisel and hammer the rust leak got worse. They squirted some RTV in the rust hole as best the could and said dont take it on long trips. The truck is a 2001 and has 122K miles with eight north east winters on it. So much for the 100K mile warrantee. I have never had a car or truck do this. The dealer customer reps are both on vacation till Aug. 13. Let's wait to hear what they have to say.

 

I've got the same problem on my 2000 Toyota 4Runner SR5, and it's been leaking for at least 2 years as far as I know. The entire cover is rusted and the fluid leaches right through the metal.

I called a Toyota dealership today and was told by the parts department that they do not even sell the cover separately, that you have to replace the entire rear differential housing, at a parts cost of at least $1000. (The actual range was $1000 - $1105, depending on model). I filed a complaint at www-odi.nhtsa.dot.gov today (thanks for the info, smilesbd!), and found 3 other complaints that were identical to mine. Hopefully if nhtsa gets enough complaints it will initiate a Toyota safety recall, as the rear differential could lock up and cause an accident (not to mention dripping fluid onto the roads). If you haven't already done so, please file a complaint either via telephone or online if you have the same defect (or any others, for that matter). The more complaints that are filed the faster it'll be addressed!

 

Thanks btw for giving the site, it was quite helpful for those who had complaints to Toyota and their 4runners... I also had the same problem as yours...

 

I wish I had come across this forum a couple of weaks ago. I thought I had a unique problem. Appearantly not.

When I asked my local dealer if my leakage was unusual, they told me that they had recently replaced several rear axle housings due to leaking pumpkin housings. This appears to be a widespread issue. I was quoted $2K to $3K for replacing my rear axle, and just over $1K to hand me a new axle housing and fix it myself. So far I have tried a "peel & stick" repair that did last a few days, before oil forced it's way out. Has anyone had a problem with the breather not functioning, possibly allowing pressure to foil cheap repairs and increase oil loss? If the housing is rusting so easily, maybe the breather is crappy too.

 

YES!! The breather was not functioning. Rusted solid as a brick. Removal and light massage between a hammer and hard place made my breather fully functional again ($12 toyota's not getting today). The soft-foil backed, peel and stick, tar based product I used, sticks like hell, but because of it's flexibility is not able to deal with oil pushing out against it. Except for the small leaking area , my patch is quite well attatched to the metal. So, I will clean it up reapply a new patch, now that I know I'll have no heat generated pressure within to deal with. I just need to make it through winter, then I can look for a replacement option. Anyone have any experience with installing a shortened Dana-60 rear end(personal choice)? Any other non stock diffs? Love to hear from anyone with or wothout leaky diff problems. Have ownd my ruuner for 10 years. May have knowledge that could help you, or shoulder to cry on (virtual of course).

 

My '02 4Runner Ltd has the same rusty differential dilemma as those listed above. This vehicle is in literally showroom condition, 65k miles, always garaged, undercarriage always washed if used in salt conditions, and virtually NO RUST elsewhere...undercarriage, frame, components and body. In short, the rear differential housing is the ONLY rust on the vehicle. Like others, the welded brackets (emerg. brake cable & brake lines) on the differential housing appear to be where the rust originally started, and from those two points spread like wildfire. I'm not talking about superficial rust either...VERY deep rust, large THICK flaking, that has seriously compromised the housing, and has caused several pinpoint holes from which lubricant has leaked.

I repaired the pinpoint holes by wire brushing, then thoroughly cleaning with solvent, and lastly, using two part putty (marine grade) epoxy, plugged each hole. The first repair lasted about one year. I am now experiencing very slight seepage, and will remove the first crappy patching and re-do. Unfortunately, there is not sufficient steel thickness remaining to effectively weld or braze a proper patch.

My local Toyota dealer states they have NEVER seen, nor heard of, any such differential rust through. They state a new differential housing is in order... to the tune of $2K +/-. Really disappointing appreciating an initial vehicle cost of over $35K, 65K easy miles, and 100% spot on maintenance.

I have no faith in the abilities or work this Toyota dealership offers, and thus will find a good used rear end and will personally install it. I will also NEVER purchase another Toyota product (this 4Runner was my third Toyota product). Although it is of little personal consolation, I know I have successfully dissuaded at least three friends from puchasing new Toyota's. I know it may seem petty, but my outspoken attitude was the result of Toyota's glaring poor manufacturing practices and even more shoddy "after the sale" customer service. Tit for tat...

If anyone has any rusty differential success tale to relate I would love to hear from you. You can email me directly via my user name link. Yep, I've already posted my complaint to NHTSA, but I'm not holding my breath for any positive Toyota response.

 

I have a 91 Runner with a V6. I was slowly getting SAS parts trying to save money but with the great deals that T-G has Im just going to order the 5" SAS kit. I already have a set of 44044 springs that I was going to use up front. Ive seen a 4Runner the was running them front and rear. How much would I get if I used them in on the rear of my Runner? I want to run a 36" or 37" hummer H1 goodyears.

 

Yep my mom just had to replace the differential in her 2001 4 Runner due to the same rust problems mentioned here. The vehicle has only 24.000 miles on it and sits in the garage most of the time. They charged her $1600. I've owned Toyatas since 1983 and have never seen or heard of such nonsense, not even with other makes. I can go to the junk yard and see differentials that have been sitting out for 30 years that are not rusted out. I called Toyota and they deny any knowledge of the problem. I feel bad because I recommended the brand to her. Can't say I'm surprised in light of the recent problems with Toyota. Never again.