V730 Temps

[gus]

The V730 is new to me so this may be kind of a dumb question.

What are your normal 70*F day oil temp gage readings for a V730 at 65 - 70 mph?

My gage reads 210* - 225* but my V730 manual says 160*F is normal operating temp. I don't see how this can be since engine coolant cools the trans oil and is hotter than that?

[luvrbus]

Gus, all depends where the sensor is mounted a sump sensor or converter temp sensor the sump sensor read the oil temperature, the converter sensor read the temp outside the converter in the housing .  
FWIW the operating temperature should be the same as the coolant from the bottom of the radiator not the engine temperature, the coolant goes through the oil coolers first then up to engine.
Check your fluid levels to low or to high will cause heat sounds like a IR  thermo gun is needed to check the cooling points and gauge


good luck

[PSmith]

Gus - My 730 stays right at the engine temp and during normal driving conditions.  When climbing up the I-17, I usually get behind a slower truck and have to stay in 1st.  I don't have enough safe room in the left lane to pass without becoming a huge PITA for others. So I just go up the hill behind the slow truck.  The point is - I try to keep the trans locked-up in first so the convertor doesn't have to work (creating heat).  This works for me and the trans likes it.  If I have to slow down to the point of 'unlocking' the convertor, then the heat starts to slowly build ( which is normal ).  Generally if all the clutches (including the convertor clutch ) in your 730 are holding, then your heat generation from them will be minimal. There is some heat generated by the bevel gearset, but it is minimal.

Bottom line ( I knew I could get here :-)

The 730 temps should stay close to the engine temps if all is normal.

PS - I'm not an expert on Auto's, but have done my share of rebuilds and have done the one in my bus sucessfully. 
phil

[gus]

Thanks guys.

Seems to me I need to check the routing of the trans cooling lines and sensor locations.

I have an IR thermo so will check with it.

[Barn Owl]

I have talked to the Allison techs several times about V730 temps. Keep it below 250 degrees and you will be OK. Do an oil analysis just like you would on your engine oil. That is one tough transmission, I have abused mine (300+ for extended periods while pulling 8-10% grades for miles on end) and I always get a good oil analysis report. I bought an oil/air cooler this winter off of Ebay and plan on having it on before our summer travels. You can find coolers cheaper than it would cost to do an oil change. I paid $100 for a NIB Hayden 1290.

[gus]

Thanks, an oil/air cooler was added just before I bought the bus.

Do you know at what temp it is supposed to cut in?

Is the sensor supposed to be on the input or output side of the air/oil cooler?

[brando4905]

Gus,

When I installed my cooler, I put the thermostat on the input side and the one that came with the unit was a 180f.

Brandon

[Cary and Don]

We mounted an air cooler for the V730 in front of the radiator added a push fan, then ran the hose back to the old cooler.  The engine temps dropped from 200 to 180.  The V730  has the temperature sender on the converter out line.  It seems to be running about 200.  These go up when we are climbing, but we aren't afraid of the hills and hot weather like we were. We got the cooler and the hoses off the Eplace.  The hoses came from some sellers that have take offs from race cars.  They were really good hoses with protective insulator covers and they were priced real right. Our engine compartment was completely enclosed so we added bilge fans to exhaust the heat from the engine compartment, vents on the transmission door with an exhaust fan.  Have sprinklers on the radiators.  The sprinklers and fans are on separate switches so we can turn them on when we need them.  The only time we need the water is on long hard climbs.  The fans are usually on if outside temps are over 90.  The whole setup probably ran about $300.  Money well spent.

Don and Cary
GMC 4107
Neoplan AN340

[Barn Owl]

Is the sensor supposed to be on the input or output side of the air/oil cooler?

Tech support told me the oil pan, but after conferencing in with an Allison Engineer, they changed and said to put it on the torque converter output. I agree with the engineer that it would be better to read the hotter oil out of the converter, and that is where I plan on putting mine. All bases covered if you put one in each location.

[gus]

Thanks guys, this gives me a lot more to work with.

As I remember from my aircraft air oil cooler days the cooler usually reduces the temp by about 50*F, does this make sense?

[gus]

Today the temps ran around 180*F - 195* at 65 - 70 mph on a 45*F day so that seems to follow the ambient temp pretty well. Now I'm wondering what will happen in 90* weather and I think I already know!

I have a feeling the air/oil cooler fan is not kicking in at 180*.

It sure runs a lot cooler at 55 -60 mph, way cooler!

[brando4905]

Gus,

If your cooler is anything like mine, when you come off the road and shut the engine down, the fan on the cooler will still be running. That's how I know mine is working.

Hope this helps,
Brandon

[gus]

Brandon,

Thanks, hadn't thought to check that but will the next trip.

[JohnEd]

Gus,

I agree with all that has been said here.  You cannot say how many degrees a oil/air cooler will drop the temp.  You need to know the oil "weight", flow rate and surface area of the cooler.  Coolers are spec-ed in BTU's OR vehicle weight.  The one for a V730 would be of the AFB size, to be specific.

Please give this some consideration.....GM and DD and Alison did a heck of a job putting together that coach.  The V730 has no rep for failure due to overheating.  You run it at 250 and you will shorten it's life.  300 should kill it much sooner.  I don't doubt that some are getting away running those temps....just saying that that isn't necessary.  I would suggest that you "fix" or repair your system and determine how much you actually need the aux cooler.

Is your trans locking up the converter?  Is your system running at full flow to demonstrate there is no blockage in the oil side?  With your IR Temp gun can you read the water temp going into the exchanger and coming out.  You can rig senders to these points by simply taping them on and wrapping insulation...temporary.  Gauges draw precious little current and a really small wire can be run, and of course, do what the mfr suggests.

Harbor freight had heat guns on sale for $29.  You absolutely NEED one of these puppies to check bearings and radiator cold spots and a ton of other tests.  Borrow one to use on this problem till yours is delivered.