Allison ht 754 fluid type ?How to get rid of air coolant ntc 400

Good nite here,what type of fluid should i use in my 1983 am915a1 allison ht754,ive seen transynd tes295 for $45 gal and read online that i can use any c4 approved diesel oil 15w 40.is there any certain answer on that ?thanks
PS. drained radiator and 2 drain petcocks ,manual says 17.25gal ,so far i have 8.5 gal antifreeze and 4.5 of water.im short 4.5 gals of water.radiator is full .is there any air bleeders or should i just run engine for awhile and wait for it to bleed itself.
?
thankksss

Just use dextran 3 on the transmission.

There is a petcock bleeder on top of the motor just behind the upper radiator hose. You can just leave the truck running for a bit and itll work it's way out

I have had and still have trucks with engine oil and I am not worried about it. When my transmission needs rebuilding if ever then I will switch out but not use Transynd as my truck will never see great high mileage. Transynd is a great product and good for Allison's that see lots of miles and need more miles before fluid changes as they could get very expensive. From what I read if it shows to change out every 100k miles then with Transynd we extend that to 300k so we save money if you had a shop do it. We had a thread where the Allison fluid engineer that said engine oil was approved for the conditions of military use. From what I got from reading the engine oil will take more heat than a thinner oil. In some military conditions the truck might see heavy loads, slow ground speed and high rpm off road that will heat up a Allison fast.

thank you guys,i think i buy some tes 295 as i will run a lot of miles(i hope so ) and ive read old threads,too many different opinions.

The only problem I see is you will use a lot of any fluid that you try and change out yourself. I believe the Allison shop has a machine that can change out all the fluid without mixing it. The problem is the torque converter and cooler lines. Seems like reading the people that try do a dump and fill then come back and change out again. That will cost you money if your trying to get all the engine oil out of the system and you might always have a mixture. If I remember the old Chrysler / Plymouth trans. had a plate you could drop and drain the torque converter. That was the best way of getting a good change out of fluid.

but they will charge me 200 bucks to change it ,isnt it the same ?and those guys always busy,tried to book 2 shops for complete investigation on this truck,both screwed me on date,brought in truck and 2 days later picked up still didnt do anything.so im kinda meh with shops.other idea ive read is to push compressed air thru cooler lines after drain,is there any danger to blow something ,lets say 10-50psi ?so i dont do double dump

Please, use caps and spacing between your sentences, it makes it a whole lot easier to read things....especially for us older dudes! Please update your location from your zip to a city.

Use your favorite flavor of engine oil, 15w40 is the proper wt. Myself, I like Valvoline. It doesn't get as dirty black as Dello or Rotella does.

Okay Sir.
Circled 10 mile trip. , Engine Temp didnt go past 150-160F .Does it need to raise up to 180-200 to open thermostat which will release trapped air ?
Idled for awhile ,temp stayed 150 and didnt budge either.
Im still short of 4.5 g of water.but cant understand where it should go.

The stat SHOULD be a 180, the gauge might be off a bit. I do not remember if the NHC has a deairation line routed to the surge tank. I can look when I go to "work" next Tuesday. The line should start at the stat housing before the stat and go to the surge tank, there is always a positive flow thru that line. It should be no bigger id than 3/8 inch, no check valve in it. Hang till tues and i'll look. Make sure the heater valves are open if you have one.

No Sir, just Will, Hey you, any thing except late for dinner!

WillWagner said:

The stat SHOULD be a 180, the gauge might be off a bit. I do not remember if the NHC has a deairation line routed to the surge tank. I can look when I go to "work" next Tuesday. The line should start at the stat housing before the stat and go to the surge tank, there is always a positive flow thru that line. It should be no bigger id than 3/8 inch, no check valve in it. Hang till tues and i'll look. Make sure the heater valves are open if you have one.

No Sir, just Will, Hey you, any thing except late for dinner!

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NTC400s in the 915s don't have a surge tank. It is radiator filled and an overflow tank. The line on the top you describe goes to the top of the radiator on the drivers side. It is right next to a bleeder valve

Sorry, thought I read 923. That is the vent line. Simp, did you roll your truck ? akita91, if your engine doesn't have it, you need to put one in.

I have that line hooked up same way between rad and thermostat.Did another 20 mile trip highway.temp didnt go past 160 or so.came back opened petcocks ,no bubbles just fluid coming out.

What are signs of bad water pump?im assuming it could be it as coolant stays still when engine running.i feel scorching heat off engine but gauge only 160f
Or i have to run it longer up to 180 to open thermo,i think 10 miles of highway is enough to raise to operating temp

akita91 said:

What are signs of bad water pump?im assuming it could be it as coolant stays still when engine running.i feel scorching heat off engine but gauge only 160f
Or i have to run it longer up to 180 to open thermo,i think 10 miles of highway is enough to raise to operating temp

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Verify temps with an IR temp gun. Never trust your gauge. Your fan is probably running all the time and it will never get to temp anyway with that going. The fan is big enough to be a propeller for a Cessna.

fan stopped at some point and turned back.im assuming i didnt drained completely and those 4.5 gallons are inside
But i flushed every petcock with 2 other being closed with tap water until its clean and bottom radiator opened as last point to drain completely then filled out.
Where i could miss something if i followed guide.

fluid doesnt blow out of radiator with open cap under wot parked.i tthink something is clogged or broken

okay,30 mile trip and temp holds at 155f ,parked raised for couple mins up to 170 then went down.whats that mean ?
am i good to go or it does need to be 180-200

I know on my 920 and 915A1 that big radiator kept things cool and if I remember both ran cold. Takes a lot of heavy pulling to heat things up as I could even flat tow a 5 ton 817 and still not heat the 920 up.

akita91 said:

okay,30 mile trip and temp holds at 155f ,parked raised for couple mins up to 170 then went down.whats that mean ?
am i good to go or it does need to be 180-200

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Did you verify the accuracy of your gauge yet?

when i bought and drove it home gauge showed about 180-190f all the way.i think it works.
https://drive.google.com/open?id=1ZmELuz4aKeZNmWzM1vNQ8I4KIfHJ2OIj
just found out beam looks bent is it ok?other is straight.
i guess thats what i didnt admit when was buying this truck as owner said he collided someone
.I thought its just bumper.