Metal transmission dipstick?

[Ol 54']

Not quite sure here but they claim automatic transmission fluid does not prevent rust. Well I have a T.H. 400 that needs rebuilding and along with that a new dipstick and tube. It seems as if all your after market dip sticks are metal. So tell me is the transmission going to be junk after about a year once the non treated metal dipstick is installed disbursing off rust into the oil?

 

[Janicholson]

If the fluid is on the metal, rust will not happen (opinion) based on 70 years of metal dip sticks in automatic transmissions. coupled with not seeing any rusted off. or in. Jim

 

[Fritz Maurer]

I think the 'no rust protection' theory is faulty within itself.

Since the case is vented to the atmosphere, it may suck in some humidity from time to time when it cools off. I have seen slight rust discoloration near the cap of the dipstick, probably from when the trans heats up and tries to expell the moisture...whether it came in the vent or through the tube when the dipstick was removed. Since there is normally no oil near the top of the tube, voila... rust.

What exactly have you seen to spur this fear?

 

[stevieb49829]

Not quite sure here but they claim automatic transmission fluid does not prevent rust. Well I have a T.H. 400 that needs rebuilding and along with that a new dipstick and tube. It seems as if all your after market dip sticks are metal. So tell me is the transmission going to be junk after about a year once the non treated metal dipstick is installed disbursing off rust into the oil?

If you are really worried about your dipstick rusting, coat it with a good rust converter before installation. But like Jim has said, there's millions of those metal dipsticks in millions of TH350 and 400's. I used to rebuild them in a dealership many decades ago, and none were ever rusty. steve

 

[used red MN]

they claim automatic transmission fluid does not prevent rust.

Who is “they”? ATF is a lubricating oil refined from hydrocarbon stock (crude oil) even most synthetic lubricants are from the same base. That said engine oil comes from the same “beginnings,” have you ever heard someone say engine oil is not a rust preventative? Bare iron will rust (iron oxide) when it reacts with oxygen, moisture accelerates this process.
Controlling the contact of oxygen with the iron is the key. You have been given several suggestions above as preventative measures. I am not sure they are needed. As Stevie said millions of those transmissions(he only mentioned a couple of GM transmission models this same configuration was used by all brands on most all ATs) with metal dipsticks and tubes and have been in service with minimal problems down the lines of rusty dipsticks. The most problematic ones that I have encountered were on vans with very long dipsticks and tubes.

 

[BarnyardEngineering]

What kind of dipstick was in the transmission before? I personally have never seen a non-metal dipstick in an automatic transmission. Some of them are 6ft long, when you're talking about the old vans.

I also personally have never seen a rusty dipstick.

 

[showcrop]

Erase that claim from your memory.

 

[Fixingfarmer]

No.

 

[T.R.K.]

The only dipstick I have seen rust on recently was in a truck I bought that had sat for quite a while. I'm in NC and the truck came from Ohio, the son who inherited it kept it a few years before selling it to me.

 

[Ray,IN]

Every transmission, engine, gearbox must "breathe" according to the laws of physics that govern warming and cooling of air. When the warm air cools, any moisture in the air condenses and falls to the bottom of thee oil. Ever seen rust on an engine cylinder skirt after non-use for years?