Best Trans Fluid

[belfert]

You can buy cheap ATF fluid for $11 a gallon and probably less if shop around.  It looks like Hytran is only about $3 a gallon less.

Are you really willing to sacrifice a $5,000 tranny to save a few bucks by using motor oil or Hytran fluid?

[edroelle]

Sean and Brian go to the "meat" of the discussion.

When have you EVER been sorry about buying the very best?  If the consequences are not important, then cutting corners is reasonable.

Dextron III/IV should be a minimum IF you always keep your tranmission temperatures low (consistently below 215 deg.) AND you change the fluid per the recommended intervals, WITH the Allison 740/750. 

With the B500/4060, with heavier loads, you want TranSynd.  Light loads and fluid changes at the recommended intervals, you may "get by" with Dextron.  But the B500/4060 is not as robust a transmission as the 740/750 series.

TranSynd is a good insurance policy to prevent an expensive transmission rebuild.

Ed Roelle
Flint, MI

[NewbeeMC9]

...  I use the advance dexron since you can get it in the gallon jugs and i cant seem to get my modulator to stop leaking. ...

Sorry for the double post, but I just re-read yours, and realized I left something out.

I hope, when you say "advance dexron" you are not talking about anything other than Dexron-III.  The newest stuff, Dexron-VI, and the older Dexron-IV are definitely NOT approved for use in the HT740.

In fact, if you've been using one of these, that might explain the leaking modulator (or might not -- I'm definitely not a tranny expert)..  If so, I would flush the tranny out and refill with Dexron-III.

HTH.

-Sean
http://ourodyssey.blogspot.com

My leak is where the Modulater goes in,  I have replaced the O=ring and that held for a while,
but it leaks when it is sitting and has started again but is much slower.  didn't have to add after sitting for a week.  used to be over night.  I'm wondering if the modulator is too tight and is pushing the housing out when you heavy pedal it.  I have upgraded the hold down to one from a Chevy tranny and then put both on when that didn't work.  If any body has had any experience here, please chime in.


Belfert,
I just went and checked a jug,  it is dexron 3/ mercon and that was on the website.  It's about 8 bucks a gallon.  I usually have to add 1.5 gallons if its been sitting a while.  I'm not thinking about changing to oil,  i had just heard that you could and found it interesting.  However if it used 40 wt, it might be convienient to carry one kind of oil .  I am a big fan of synthetic lubricants and try to use them wherever possible.  

[justin25taylor]

You can buy cheap ATF fluid for $11 a gallon and probably less if shop around.  It looks like Hytran is only about $3 a gallon less.

Are you really willing to sacrifice a $5,000 tranny to save a few bucks by using motor oil or Hytran fluid?

Not me! I would never use anything other than ATF just wondering if you guys had heard similar stories.

[Stan]

I haven't read the specs on the 700 series for a long time but Allison used to specify Dexron for light duty use and C4 oil for heavy duty use. Read the Allison specs and use your own judgement as to what is the best for your application, taking into consideration the type of driving, the annual mileage and of coarse the cost. BTW, most motor oils and hydraulic oils meet the C4 specs.

[TomC]

Just to add to that, Freightliner along with Sterling and Western Star all have Castrol Transynd as the STANDARD transmisson fluid when an Allison is spec'd-what does that tell you with the largest truck manufacturer in the world? (when also considering the Daimler side of things)  Good Luck, TomC

[belfert]

TomC, hasn't Transynd been the standard factory fill from Allison for several years?