dS8

Please give us his name and number.

tonypai

I put in a brand new TC and it still hunted. It wasn't until after Tozo adjusted the valve body that the hunting went away.

The TC hunts because the valve body tells it to, and because of the hunting the TC wears out quicker.

ditchpickle

If what you say is true "The TC is not the cause of the hunting" how do you explain my car? My car hunted, I had the TC rebuilt, it no longer hunts. The same valve body is in the car, would it not be telling the rebuilt TC to hunt as well? The only thing I could possibly conclude is that in mine it could have been a combination of a bad TC and a valve body problem. My VB was cleaned prior to the TC rebuild and it did not help. But knowing the condition my TC was in I dont know how it could have helped. So maybe a VB was the root problem and the TC rebuild was what finally corrected the problem.

tonypai

Something in the valve body is wrong (ie, sticky valve) it tells the TC to hunt. A newer TC resists the hunting for a while but eventually it wears out, that's why many people didn't have tranny problems until 60-70K miles.

My guess is that your hunting will come back. But perhaps not, maybe your mechanic fixed your valve body.

I know Tozo put in a used 02 tranny/valve body and the hunting stopped but when he swapped the 02 valve body for his 97 valve body it hunted like crazy.

My car didn't stop hunting until Tozo adjusted the valve body.

I'm not an expert nor did I stay at a Holiday Inn last night, so take it with a grain of salt.

CalG

This reference from Sonnax Corp. provides much fodder for fueling conversation regarding Transmission issues.

http://www.torqueconverterparts.com/TJ/tcjournal.htm


If the TCC were truely "metal to metal", Shudder would be noticed. I will bet the condition observed during the rebuild was "real thin". but the liners start "real thin" from the beginning.

Question: By what mechanism could replacing friction material effect the "thump"? May that problem may be addressed through TC shaft seal service?

I do believe "enhanced" TCC materials might accomodate a TCU/ VB control deficiency. That's fine, especially if the fix lasts more than 60K miles.
If it lasts less than that, is it truely a fix?

Does anyone have a report on the least reported milage number where hunting and thumping has been experienced on originally equiped vehicles? (to establish a wear index)



Regards

CalG

tozoM8

The clutch plate is attached to the turbine and rotates the transmission input shaft. The clutch material is glued to the bottom of the TC housing and it bolted to the crank shaft.
The impeller also mounted to the TC housing.
With open TC the impeller trows the fluid to the turbine and drives the car. When you come to a stop the impeller rotates with engine idle speed the turbine stops with the car (transmission in gear). Because the TC is open and the whole TC is driven by fluid you can stop without stalling the engine.
When your car is up to speed with light or moderate throttle the TC will lock the turbine to the TC housing with the clutch plate. To make a firm but smooth lock, the clutch plate (tranny speed) is pushed against a clutch material in the TC (engine speed). The clutch material is like 3mm thick (not enough to resurface and the turbine would go further from the impeller). Yours was probably on the lowest limit. If it gets to steel to steel it scratches up badly in minutes. The clutch plate is only 2mm thick steel. There is not enough material to resurface and you would meed to rebalance it too. It the TC is rebuild-able, they take the clutch material out, clean the surface and glue new clutch material in, re-weld the housing and balance the whole TC.
There is another clutch between the impeller and the turbine. It's called stator. It has a one way clutch in it. If the TC clutch material wears out completely the steel plate rubs against the bottom of the TC and the metal shaving locks up the one way clutch. Because of the high rpm it destroys the TC in minutes (it recently became a problem with BMW TCs making the rebuild expensive). No reputable TC re-builder would touch a scored steel to steel TC clutch.
I am sorry if I sounded like a d*ck yesterday, but if you understand how the TC works you know your mechanic's TC re-builder was full of it.
<img src="http://pictureposter.audiworld.com/80919/dscn0953.jpg">

CalG

Tozo

Thanks for cutting one open for all to see!

Can you help my understanding please?

Does the the TCC disc slide on the shaft with a spring behind and oil pressure, this would require both a bearing and seal on the center shaft. Or does the entire plate flex like a large diaghram and thus need no bearing or seal.

Also, how does the fluid exit when the control calls for lock up?

I'm trying to get an idea about how the fluid pressure is maintained in order to limit cavitation, and still allow pressure differential across the TCC to allow the spring self energizing to effect controlled slip and lock up.

I still scratch my head and question how messing with the electronics, sensors and TCU can make a difference if the defect is "hard parts.

Tozo: Thanks so much for sharing your practical experience and knowledge.

Oh Here is a link with nice photos showing a TC rebuild


Regards

CalG<ul><li><a href="http://www.transmissiondigest.com/tech/TCTech/200512/200512TCT.htm">http://www.transmissiondigest.com/tech/TCTech/200512/200512TCT.htm</a</li></ul>

tozoM8

The turbine is splined to the input shaft and the outer edge of the turbine has fingers that locks with the clutch.( pic 2-5-6-8) The fluid exits on the center of the input shaft. You can see the seal on pic #3.