Torque Converter lockup delayed?
 

Hey all,
When I start my SVX for the first time each day and drive off it takes about 7 to 10 miles of highway driving before the converter locks. After this initial delay the converter locks up right away. It seems to lock up firmly. I don't know if it took this long for lock up before the 4.44 legacy trans was installed because I purchased it with the tranny bad.

Is this normal?

Steve

Yeah, the transmission has to warm up to a certain temperature before it will allow TC lock up. I forgot what that temp was. But that's normal. (Both the temp thing and my forgetting...Both are normal. :D )

In my case the tranny shifts to 4th pretty much right away, but it still takes a very long time for the converter to lock the first time. I don't think I've driven the car yet when the ambient temperature was below 50F.
Steve

It's more like 150 degrees before the TC locks; at this time of year, with a mid-sized, supplemental ATF cooler, I'm nearing the end of my 12-mile commute when I feel it hook up.

dcb

On the stock SVXi I drive, it takes about 7 miles in the mornings before they lockup. On the 4.44s, it takes longer, and is less noticable.

On my 4.44 geared SVX with an aftermarket 16,000lb GVW trans cooler mounted on the radiator, it takes about 2 miles or 4-5 minutes before my t/c locks up.

I plan on relocating the trans cooler to my driver's side fender this weekend or the next. I'll see how much longer it takes afterwards...

-Chike

That's my experience too. On highway trips in the winter, any time my ATF temp gauge dropped below about 140F, the TC would unlock.

My experiences showed I get 4th gear at 50°F, TC lockup at 150°F and TC unlock if the temp dropped below 100°F

I know one thing: Mine goes much, much farther on a gallon of gas with the torque converter locked, provided the RPMs are high enough to keep the engine from lugging.

dcb

Cooler.
 

The time for the converter to lock depends on the ATF temp. While the converter is working it will produce heat in the oil, when the oil reaches operating temp, it will lock.

When a additional cooler is fitted, it should be fitted in series, before the orignal cooler in the radiator. This allows the extra cooler to reduce the oil temp, and the water cooler to stablize the oil temp, allow it to heat up to temp faster.If the extra cooler is fitted after the orignal, it will cool the oil temp back down,to a lower temp that will keep the converter unlocked for a longer time.

Subaru used a oil/water heat exchanger, as all cars do, for this reasion.

Harvey. ;)

Thanks for all the info.

It sounds like my SVX is shifting the t/c as it should.
Steve

Harvey - My ATF lines do not go through the orignal radiator. The added external ATF cooler is located in front of the water radiator. Could this be keeping the oil cold enough to be the reason my T/C never locks-up? I've had the car since last winter and have never seen lock-up. This includes driving it this summer in the city and on the highway with temps over 100F.

- Jim

Not to step over Harvey (who has forgotten more about cars than I'll ever know), but the simple answer is, if that external cooler is big enough to keep the ATF from reaching 150 degrees, then yes, your TC will never lock.

dcb

Cooler.
 

Feel free Darrell, :)
Yes Jim, that happens, a lot of people took it out of circuit when it blocked. and just fitted the air cooler. What they should have done is reverse flush the cooler to remove the debri, and fit a filter to prevent it from happening again.When the extra air cooler is installed before the water cooler, it then will remove the high-end heat, then the water cooler can stablise the temp to normal operating temp, so the trans will operate normally.

Harvey. ;)