logic behind no trans dipstick?

Joined
Jan 7, 2003
Messages
631
Location
New Jersey
Hi,

Exactly what is the car manufacturers logic in moving to eliminate the dipstick for automatic and CVT transmissions? Is it to say you have a "sealed transmission" and it's a "lifetime fluid"? Any here know that is nonsense. And how would you even know if the service for a drain and refill or a flush was ever really dont since you can not confirm it WITHOUT a dipstick to check??
 
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Mostly the cost of not having to hang a dipstick. Also brings more people in with bad trannys 8 years later. Another factor is amatuers not understanding how to check and fill properly at operating temps.
 
Because in the analysis of numerous transmission failures at GM, rag lint was found contaminating the valve body and causing the failure.

Whether professional or amateur mechanics were that careless doesn't matter. Careless mechanics caused failures and warranty claims.

It was decided that non-serviceable transmissions were less likely to have warranty claims.
 
There were 3 reasons;
1) To stop incompetent DIY doing damage or incompetent mechanics
2) To create more business for dealerships
3) To save on the cost of the dipstick set-up.

that's the order of importance according to what I've heard from people in the business.
In Fact if any transmission failed and had to be replaced under warranty the whole unopened transmission including fluid had to be shipped to the manufacturer so that it can assess the reasons for failure. 2 & 3 are corollaries of 1
 
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Originally Posted by IMSA_Racing_Fan
The logic: transmission last the warranty period. Transmission then dies, you get a huge repair estimate, you buy another vehicle.


Or:

Inept mechanics kill transmissions. Protect transmission from ineptitude by sealing it.
 
I keep a can of compressed air handy when doing an AT fluid flush. Before inserting the the dipstick it gets a shot of air.

Sam
 
My understanding is that one of the big things that degrades fluids is exposure to air, and the very small amount of moisture that condenses out of the air and into the fluid. Over time that can add up to a lot of oxidation and moisture. When you have a dip-stick every time you go up or down a mountain, or the barometric pressure changes a small amount of air moves in or out of the air space above the fluid in your trany. When it moves in it carries new oxygen and water molecules (moisture). Some of that interacts. A sealed system does not have the fluid degrade anywhere near as fast.

I have seen some engineering specifications for some fluids and there useful life that specified different life expectancy for use in sealed and unsealed systems.
 
Performing a drain and fill on an 8HP isn't too bad. A thermometer can substitute for a "scanner" although my Carly app can also read the ATF temperature.
 
The Osprey military aircraft has a filter containing material that absorbs moisture from the air before it can enter the area where the fluids are for all that is going on inside it mechanically. That filter has to be changed when required to keep moisture out of the fluids.

Moisture is a big concern with fluid performance and life.
 
1 less part to install/worry about. Also when cars are reviewed they add up all the repairs/maintenance a car will need. So if something is "lifetime" then no cost added vs the other car might say every 40k or something. So then car A looks cheaper to keep up then car B. Yet in the real world car B has a dipstick and drain plug so $20 and 30 minutes you change the trans fluid. Yet car A has no dipstick so it has to be lifted flat, temperature has to be in a specific range, etc... so it cost a lot more/take a lot more time to do.
 
Originally Posted by Sam_Julier
I keep a can of compressed air handy when doing an AT fluid flush. Before inserting the the dipstick it gets a shot of air.

Sam

confused2.gif


I put on my favorite Johnny Cash album and dance a two-step jig before attempting any repairs/maintenance.
Been successful at keeping my cars on the road for several years.
thumbsup2.gif
 

"I put on my favorite Johnny Cash album and dance a two-step jig before attempting any repairs/maintenance......"



Now THAT'S something I would love to see!
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Not having a dipstick or a dipstick and a tube saves the builder several dollars per car. Lets say $4.00 per car x 1000000 cars and you get a huge savings to send to investors instead.
 
Originally Posted by Lolvoguy
Originally Posted by Sam_Julier
I keep a can of compressed air handy when doing an AT fluid flush. Before inserting the the dipstick it gets a shot of air.

Sam

confused2.gif


I put on my favorite Johnny Cash album and dance a two-step jig before attempting any repairs/maintenance.
Been successful at keeping my cars on the road for several years.
thumbsup2.gif



I think Sam is keeping lint and dust off the dipstick so that it's not introduced to the transmission.

If more mechanics, both amateur and professional, had his level of care in their work, OEMs wouldn't have needed to seal transmissions.
 
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