Torque converter question

[mh434]

Hi all
I dropped the transmission this morning and have a question. If I hold the centre of the torque converter I can move the converter maybe 1/8 inch or more up and down. Is that normal ? Doesn’t seem right to me but I’m not familiar with COM’s. As always, appreciate your comments.
Jon

[jopizz]

Many times the front pump bushing is worn. I would replace it along with the front pump o-ring and the front seal. A worn bushing will cause even a new seal to wear and leak.

John

[mh434]

Thanks John
Are all the bits readily available through the usual suppliers ?

Jon

[jopizz]

The front seal is readily available. My local transmission shop was able to get the other parts without any problem but I don't know what source they used.

John

[mh434]

Thanks John

[jopizz]

You're welcome. If you can't find the parts let us know. I'm sure we'll be able to track them down.

John

[simplyconnected]

Your torque converter is centered and bolted directly to the flex plate (and the crankshaft). The transmission case is dowel pinned and bolted to the engine block.

If you think about it, 'slop' between the two is very confined. I've seen plenty of failed seals but never heard of 'slop' as being a cause or an issue. When transmission bearings wear, it's the internal end that is usually the cause because those parts slide on a splined shaft. Worn engine bearings can cause the transmission's front bearing and seal to fail. - Dave

[mh434]

Mmmmm good point Dave about the converter being fixed so there shouldn’t be any run out that would cause an issue with the pump bushing. I’ll investigate a bit further next week.
Jon

[simplyconnected]

Right Joh, it's a 'system' because the engine and trans are dependent on each other.

The center crankshaft bearing is a thrust bearing that allows a little lateral motion. The torque converter uses a center-shaft that is splined to allow for that same crankshaft motion.

When ever I marry the engine and trans, I always install the torque converter to the transmission first, then rotate the flex plate as I offer the trans to the engine and tighten the four converter nuts. This prevents damage between the pump and converter.

I also mark the flex plate and converter before disassembling, just so I don't cover the converter's drain plugs by using the wrong flex plate holes. - Dave

[jopizz]

All that being said when I had the transmission in my '59 redone he showed me the old front pump bushing and there was very little left of it. He said that caused the new front seal that I put in to leak. Since he's been doing Ford transmissions for over 50 years I have no reason to doubt him.

John

[pbf777]

Your torque converter is centered and bolted directly to the flex plate (and the crankshaft). The transmission case is dowel pinned and bolted to the engine block. If you think about it, - Dave

And, when one does, and or examines the components involved, you are correct. Except, unfortunately the flexplate in its' plane perpendicular to the centerline of the rotation, is not intended nor of adequate design to locate or support the converter from deflexion or "whip" at the snout where it enters the transmission's front pump section, hence the purpose of the bearing surfaces at this juncture, and impending loads, and consequential wear, which if excessive will lead to leakage as the radial movement permitted will exceed the capacities of the seals' design.

Scott.

[simplyconnected]

Thank You for your explanation Scott but, many millions of cars are a testament that converters and flex plates are engineered correctly. There should never be any 'whip'.

A front transmission bearing failure is unusual unless something is terribly wrong. Converters are welded, machined and balanced. They're also very heavy when filled with transmission oil. Add 5,000-6,000 rpm, and you better hope this thing runs true. If it doesn't, the engine will usually vibrate as an early warning.

Considering a history of hundreds of millions of cars and trucks of all brands, most go to their graves with the original front trans bearing and seal. That tells me the front bearing rarely sees friction unless any of these converter problems exist:

• An internal vane broke loose in the converter,
• A mounting stud was welded off center,
• The converter was never correctly balanced or it came out of balance from a weight that flew off,
• The converter bloated and distorted its shape. (I've seen witness marks from crankshaft flange bolt heads embedded into the face of converters.)

John, your trans guy may have identified the effect but not the cause of a failed bearing. I would ask him 'why', to continue troubleshooting to the root cause. Changing a bearing and seal only fixes the leak temporarily. I'm surprised he didn't see all that metal glistening in the old fluid. BTW, OEM torque converters are reasonably priced. - Dave

[jopizz]

Since Ford and other parts manufacturers sell the front pump kit that includes a new bushing, seal, o-ring and gasket I assume it's something that has a failure rate from normal use.

John

[mh434]

Crikey, what have I started.....!
I’ll let you know what I find.
The only thing I would add is that Dave mentioned that converter problems could manifest themselves as engine vibration. My engine runs (before I pulled it apart) like a Swiss watch..
Jon

[jopizz]

Crikey, what have I started.....!
I’ll let you know what I find.
Jon

There's nothing wrong with differences of opinions as long as it's kept civil.

John