So, naturally, my steering box is leaking. It looks like power steering fluid is in there. I'm going to do a system flush and add the appropriate Dextron III ATF. I'm thinking of using some leak stop to help at least slow down the leak until I can rebuild the box. First, is that a good idea? Second, since ATF will be in the system, do I use transmission leak stop or power steering leak stop? I'm not sure how the the leak stop fluids work work, so I need help here.

I'm driving a 1990 4Runner, 3.0L V6, 4WD

 

Unless you are stuck on the side of the road in death valley, in the middle of the Sahara or way out in the Australian outback. No never use a magic bottle, stop leak type, product.

 

Well, alright. I won't ever be in any of those situations, so I'll stay far away from the magic bottles. Thanks!

 

I'm curious as to why you would give such a warning. I used Leak Stop in my 86' 10 years ago after it started leaking after I adjusted the steering slack. I just checked the fluid level and it still looking good.

 

On a PU I recently bought, there was PS fluid in the PS reservoir and a leak at the gearbox. I replaced the PS fluid with ATF (the correct fluid) and the leak has gone away. Not sure how long that will last but putting the right fluid in is a good thing to try.

 

The problem isn't that stop leak doesn't work, it is actually that it works too well.

If something is leaking, a seal has failed or something is loose. Stop leak products do not magically fix a bad seal. The bad seal is still there. Stop leak products only try to fix the symptoms of a bad seal.

Cooling systems are negatively affected the most by stop leak products.

Stop leak type products are designed to plug up holes in a system and can inadvertently clog up fluid passages and can coat the insides of passages and pumps.

Sometimes the clogged passages can lead to system failure.

When it comes time to rebuild a part in that system where stop leak was used (especially the cooling system) it often turns into a lengthy project trying to remove the stop leak product from the entire system.

Problems from stop leak don't always happen (probably your case) and there have been many people who swear by it, but the gamble is not worth it in my opinion.

If "mechanic in a bottle" products always worked, we wouldn't need mechanics!

What it comes down to is short term gains, long term losses in most cases.

 

Great explanation, better then just saying not to use it!