Transmission Stall Test

[sowise]

When doing a transmission replacement with a used 4EAT (stock, 4.11, or 4.44) has anyone here done the stall test as a check out? Is this not recommended for used transmissions?
I know it is supposed to check the condition of the clutch and brake band, torque converter operation and engine performance.

I think I was have my stomach in knots if it didn't perform well right after an installation but I guess I would rather know than not.

[oab_au]

Originally Posted by sowise

When doing a transmission replacement with a used 4EAT (stock, 4.11, or 4.44) has anyone here done the stall test as a check out? Is this not recommended for used transmissions?
I know it is supposed to check the condition of the clutch and brake band, torque converter operation and engine performance.

I think I was have my stomach in knots if it didn't perform well right after an installation but I guess I would rather know than not.

I don't think it would be worth doing.
It will only test the forward clutch, Torque converter and the engine power. It should stall at about 2500, but it will produce a lot of heat in the ATF, so it should only be done for a few seconds.
If the speed is higher it can be the forward clutch slipping, or the torque converter stators one-way clutch slipping. If the stall speed is lower, it is likely that the engine power is down.
Just remember that while you are doing it, all the engines power is turned into heat.

Harvey.

[sowise]

Sounds pretty much like what I read in the manual. I am considering doing a full check on the 4.44 trans after install. I bought it used but I don't know much else about it. I am considering doing the Stall Test, Time Lag Test, and if I can get the gauges I would like to get the Line Pressure/ transfer clutch pressure tests. However I am thinking it may be better to characterize the transmission doing the road test and check those results before trying the other tests. I know it can't be good to do it for more than a few seconds but it would give peace of mind to know if it was solid and passed everything with flying colors.

[oab_au]

Originally Posted by sowise

Sounds pretty much like what I read in the manual. I am considering doing a full check on the 4.44 trans after install. I bought it used but I don't know much else about it. I am considering doing the Stall Test, Time Lag Test, and if I can get the gauges I would like to get the Line Pressure/ transfer clutch pressure tests. However I am thinking it may be better to characterize the transmission doing the road test and check those results before trying the other tests. I know it can't be good to do it for more than a few seconds but it would give peace of mind to know if it was solid and passed everything with flying colors.

The test is for diagnosing a problem, it will really only test the forward clutch. The band and high clutch can't be tested. The lag test was to test for a leaking pump gasket, that was only on the early boxes, the later ones did not have this trouble.

I would try it on the road to check the band in second and top gear, that may have been treated badly. Look for a flair going into third, and look for the box going back and forth to third when driving slow in 4th. band slipping.
The later boxes are very good.

Harvey.

[sowise]

Thanks! Always nice to bounce ideas and options of smarter people.

[Trevor]

Originally Posted by sowise

Thanks! Always nice to bounce ideas and options of smarter people.

The smart answer is that a proper stall test, carried out in all drive ranges, can detect possible slippage involving :-

The forward clutch, brake band, reverse clutch, low and reverse brake and one way clutches.

General slippage throughout will mean that line pressure is suspect.

[oab_au]

Originally Posted by Trevor

The smart answer is that a proper stall test, carried out in all drive ranges, can detect possible slippage involving :-

The forward clutch, brake band, reverse clutch, low and reverse brake and one way clutches.

General slippage throughout will mean that line pressure is suspect.

No that is wrong. The brake band is not involved in a stall test.

Harvey.

[sowise]

Ok, hopefully this helps

[Trevor]

Originally Posted by oab_au

No that is wrong. The brake band is not involved in a stall test.

Harvey.

When knowledge is absent, one should check the manuals, i.e. --- section 3 -2 -3; - Performance Test; B - Stall Test, 3 - Evaluation.

[oab_au]

Well you can put the lever in 2nd or 3rd, but it will still be in 1st with the forward clutch on. The box won't apply the band till the road speed increases. I suppose you could try the Manual button.

Harvey.

[Trevor]

Originally Posted by oab_au

Well you can put the lever in 2nd or 3rd, but it will still be in 1st with the forward clutch on. The box won't apply the band till the road speed increases. I suppose you could try the Manual button.

Harvey.

Well, I would be certain rather than suppose, that this thread refers to a stall test. A stall test definitely involves selecting all drive positions, i.e. including "putting the leaver in second or third positions."

A stall test by description, does not involve road speed. You side step by claiming that the Subaru manuals are wrong. I do not agree.