HT 740 with Transynd

[Seangie]

Biting the bullet and going to Transynd on my 740.

Questions -

How many gallons for the change?  I'm assuming 10.

How many miles before I need to do my second change of fluid?

Thanks guys!

-Sean

[bevans6]

What do you have in it now?  My question is how do you change the fluid trapped in the torque converter and the cooler/filter?  I've heard on some transmissions you need to do three complete changes to get the fluid in those two traps, if you can't drain them separately...  I guess the fluids are all compatible, but running whatever you choose as pure as possible would be the ideal, I would think.

Brian

[Seangie]

What do you have in it now?  My question is how do you change the fluid trapped in the torque converter and the cooler/filter?  I've heard on some transmissions you need to do three complete changes to get the fluid in those two traps, if you can't drain them separately...  I guess the fluids are all compatible, but running whatever you choose as pure as possible would be the ideal, I would think.

Brian

Brian -  Dexron is what's in it now.  Just talking to the mechanic and he said the same thing about the torque converter.  He wasn't sure what the process was for the change.  (If there is a drain on the converter or if we need to run it a few hundred miles and drop it again) 

Seemed to be more work than it was worth.  Was totally ready to pony up the $$$ but just don't have the time at this point.  Ill probably do it myself at some point in the future.

So now its back to Dexron.  Any reccomends on II or III or IV?

I'd assume the latest (IV) but want to make sure before I go messing with anything.

Also - anyone know if I'll need 10 gallons for the change?

Thanks.

-Sean

[luvrbus]

Don't use the Dexron IV synthetics are a waste of money in a 740,sometimes depending on the clutch pack material used it causes more harm than good just use 10/30 or 15/40 engine oil the 740 will love it   

[Seangie]

Don't use the Dexron IV synthetics are a waste of money in a 740,sometimes depending on the clutch pack material used it causes more harm than good just use 10/30 or 15/40 engine oil the 740 will love it   

Awesome. 

Thanks Cliff.

That's the perfectly fantastic answer I was looking for.

-Sean

[Seangie]

Well all's done. The tranny only dropped 5 gallons and only took 5 gallons.

I'm sure we are missing something somewhere but its what it is for now.

Ill learn a thing or two from this and add it to the list of things already growing.

Thanks all for the help.

-Sean

[luvrbus]

What's the depth of the pan a 6 and 7 inch pan holds 33 qts the 8 inch takes 38 qts  

[HudsonMarine]

Don't use the Dexron IV synthetics are a waste of money in a 740,sometimes depending on the clutch pack material used it causes more harm than good just use 10/30 or 15/40 engine oil the 740 will love it   

Really???
Motor oil?
(not sarcasm, wanting to k now)

[luvrbus]

Really???
Motor oil?
(not sarcasm, wanting to k now)

C rated engine oil has been approved for use in the older Allison since the beginning, the 8000 and 9000 series off road Allison 15/40 was the only approved oil.A lot of people here on the board use engine oil in the 500,600 and 700 series Allison     

[scanzel]

Back in the 60's when I was in the army reserves we had GMC deuce and a half's with the hydromatic  transmissions they used engine oil so you didn't have the have two different oils available in the field. When the government sent them to surplus people would buy them and change the engine oil to automatics trans fluid. Guess what they burned up the trans and now you had a piece of 2&1/2 ton junk that wouldn't move. Heard many stories of this happening.

[B_K]

Yup I switched all our older buses over to 15/40 back when we were running 740's and they loved it!
I was skeptical of doing it at first but I spoke to a guy who made his living building them.
And his response was "Yeah, we use it in heavy duty/hard use applications all the time."
I asked what he meant by heavy duty/hard use and he said "OH you know garbage trucks, fire trucks, dump trucks stuff like that."
I asked what about buses? He said "Hmm don't guess we ever put any in buses, but should work fine."
I laughed and told him "You haven't paid much attention to hired bus drivers have you?"
He said "I guess not what do you mean?"
I told him "hired drivers have 2 modes flat on the floor on the throttle or flat on the floor on the brakes!"
He laughed and said "OH so their just like garbage, fire, & dump truck drivers then!"

SO I changed our buses w/740's in them over to 15/40 an they loved it shifted lots better!
  BK 

[HudsonMarine]

OK then, is there a specific brand/type I should be looking for?
And is there any harm in switching from the Dextron that is in it now to the motor oil?
I'm running Delvac 1300 super in the engine, that has several "C" ratings listed on the label.

[lostagain]

I too switched from Dexron to 15W40 "C" rated motor oil in my HT740. Seems to shift a little smoother, and run a little cooler. I still have to change it a second time to get rid of more Dexron. I also added a second filter on the line between the converter and the oil cooler on the side of the engine.
JC

[luvrbus]

Any good C rated 15/40 will work just don't use S rated for gasoline engines Delo 400, Mobil 1300, Shell Rotella and so on,the Dexron 11 is getting hard to find were I live   

[HudsonMarine]

Any good C rated 15/40 will work just don't use S rated for gasoline engines Delo 400, Mobil 1300, Shell Rotella and so on,the Dexron 11 is getting hard to find were I live   

Just to clarify sir, the oils you listed are OK or, they are NOT ok?