V730 Shifting Problems

[Iceni John]

Are you checking at Cold Idle or Hot Idle?   My HT740 Mechanic's Tips manual says to normally check only at Hot Idle (I can't remember what temperature is defined as being hot enough), and that checking at Cold Idle should only be done when the transmission is being initially filled after service, or something like that.

John

[eagle19952]

On big rig engines and transmissions, when indicated that it is at the low mark, that means to add a gallon, not a quart. Good Luck, TomC

depends on a lot of things..temp is one. but adding a little at a time is a lot easier than taking a cup full or 3 quarts out...over full is just as bad as not enough.
Good Luck, DonaldP

[chessie4905]

Eagle makes a good point.Unless you have a noticeable significant leak, and the problem is low fluid level, or it it from small leaks/ drips over time, adding a quart and then road testing it would be better than using a whole gallon and then end up removing it.Btw, removing governor is easy. Remove four bolts, remove cover, remove governor by rotating slightly as you pull it out. Put a catch pan underneath to catch any spillage of fluid.

[Geoff]

I don't think anyone has mentioned that there is a 3rd gear low fluid shift inhibitor switch when the V730 is one gallon low.  That is why you dump a gallon in to see if 3rd gear comes back.

--Geoff

[Friday1]

For those with an air throttle, do you use an air regulator between the throttle slave servo? Or do you just use the same air pressure as at the servo? If you use a regulator, what is your pressure at the modulator. I had a Wanderlodge and put air throttle on it and had to regulate it down or it would not shift until the engine was almost on the governor. I have the V-730 in my 4106 and put an air throttle on it. The PO had the tranny rebuilt shortly before i bought it last March and the shop that did the rebuild could not get the old cable between the engine and tranny adjusted properly so they removed the cable assy. I live in the flatlands so if I need to downshift, just move the selector. I have the air modulator, just have not installed it.

[chessie4905]

It has been emphasized here to make sure that the line to the modulator and to the throttle be same length and diameter.

[luvrbus]

No one here ever does it but you are supposed to have Bendix DC-4 valve at the slave to prevent a back flow 20 to 25 bucks and it makes a difference in the down shifts 

[Beesme]

Do you need the check valve on a 740 ? Mine sometimes down shifts rough . Back to the 730 mine when low also misses 3rd add a quart and she shifts great! I can usually tell when it's starting to get a little low .

[luvrbus]

I always use the DC-4 on the 740 ,all military trucks with air throttles and Allison's use the DC-4 valve 

[richard5933]

Update on where this all sits for now...

The bus is back at Interstate this week. They had a few loose ends to tie up from their work earlier in the month. I had them look at the transmission while it is there. They found two things.

1 - The tach is pretty far off and is reading a much higher than actual engine speed. Transmission does shift all the way through the gears if pushed to proper speed. I was afraid to push due to the false reading on the tach.

2 - The tech tweaked the settings on the transmission governor. It sounds like they were close but he felt that they could use a bit of adjusting.

Apparently they now report that the transmission is shifting properly. Guess I'll have to find a new tach to work on the bus. Luckily the pulse generator and wire from engine bay to tach are all intact. Just need to order the tach.

Now if only he could get the Jake brakes to work properly (if it's not one thing it's another...)