HT740 modulator.

[TomC]

I appears my modulator is leaking. Is it resealable? Or do I just need to replace it? Can I do the replacement? Is there a secret to replacing it? Thank you. TomC

[luvrbus]

Easy to rebuild a couple of o-rings and a gasket ,just be careful not to drop the pin when you remove it, sucks to remove a pan for a pin

[TomC]

Is there a rebuild kit I can buy to get the proper O-rings and gasket?

[luvrbus]

Is there a rebuild kit I can buy to get the proper O-rings and gasket?

Luke may sell one, but I never bought one.is it leaking on the outside or under the cable cover?.those are made by Morse

[TomC]

I'll have to get under for a closer look. Luckily with it being a truck, I don't need to jack it up. Good Luck, TomC

[TomC]

It appears to be leaking from the shaft going inside the transmission. Good Luck, TomC

[luvrbus]

It appears to be leaking from the shaft going inside the transmission. Good Luck, TomC

There is just 1 o-ring on the shaft easy job but you will lose some oil,I can change those with the engine running and not lose fluid, but it is very un-comfortable laying under a truck or bus with the engine running

[TomC]

You take the bolt out and the hold down. Does it just pull out or is there a trick to it? Good Luck, TomC

[luvrbus]

You take the bolt out and the hold down. Does it just pull out or is there a trick to it? Good Luck, TomC

Yep remove the bolt and pull it, there is a pin that will stay hopefully in the valve body, keep a eye on it if you drop the pin in the pan it will not shift when reinstall the modulator lol I have a stock of pin every 740 pan I remove has a pin in the pan so I have extras in case you do drop it

[TomC]

One more question Cliff-how much room do I need to pull the modulator out? I have an air tank right next to the modulator. I need to know if I should remove the air tank first. Thanks! TomC

[buswarrior]

Luke always recommended PM changing out some mission critical plastic part in there.

If it breaks, nothing works.

HTH

Happy coaching!
Buswarrior

[luvrbus]

One more question Cliff-how much room do I need to pull the modulator out? I have an air tank right next to the modulator. I need to know if I should remove the air tank first. Thanks! TomC

To make it easy you will need at least 4 inches

[TomC]

I removed the air tank. And then easily removed the modulator. I don't believe anything fell out. The middle pin stayed in the transmission. I replaced the O ring with what looked like the same size, but not realizing the old one was shrunk, continued to leak. Pulled it again and put a bit larger O ring in and it appears to not be leaking now. It appears about a gallon of fluid came out. Will remount the air tank and add a gallon and be done. Thank you for all your help! Good Luck, TomC