The 740 Allison and Dexron IV fluid

[makemineatwostroke]

I thought I would pass this information to you guys when at Stewart & Stevenson Tuesday visiting some friends went out in the Allison shop and they are having a lot of clutch failures on the 740 now and Bill the shop foreman for 22 years thinks it the Dexron IV causing the problem on the older transmissions the clutch packs are just deteriorating  and they have never had that problem before and are not having it with transmissions that were rebuilt about 4 or 5 years ago with the new clutch packs or with the ones using C4 15/40 ,Transynd or the operators using the Cat T04 10 W oil only with Dexron IV.He suggests if you have a older transmission try and find Dexron III it's out there just hard to find if not change over to C4 or Transynd but at 10 bucks a quart for Transynd that's over $400.00 and you have to do it twice.Like he said the oil companies say it not their fault and Allison does the same but it is definitely a problem with someone because the 740 is the best auto ever built  just some info for you guys

[dickegler]

I was having trouble, never heard of Dextron 111, then it dawned on me  DEXTRON 3.

a little behind somedays.

thanks for the valuable information!!

dick egler

[belfert]

A little clarification on having to change Transynd twice.  If the transmission was not using Transynd from new the first fluid change after going to Transynd must be done on the schedule for non-Transynd fluids.  After two changes with Transynd the extended drain interval can be used.

You should not have to change Transynd twice immediately.  The big win with Transynd is the time limit for changes is extended from 12 months to 48 months once the transmission is running 100% Transysnd.  Most of us won't drive 25,000 miles in a year (regular drain interval) or 100,000 miles (HT700) / 150,000 miles (B500) (extended drain interval) in four years to warrant changing on mileage.

Having said all this, I doubt there are too many bus conversion owners who rigorously change their tranny fluid per the 12 or 48 month schedule.  I had my B500 changed to Transynd in July 2007 and I doubt I'll have the fluid changed again this year even though I really should.

[luvrbus]

MM2, they man may be right my FS 740 failed last year after 15 years of trouble free service I started the bus one day and nothing and it worked fine when I parked it.The folks at United Transmission told me they had never saw a 740 clutch pack turn to mush like that but could not give me a reason.I serviced my transmission every 12 months with Dexron regardless of the mileage and never paid any attention to what number was on the jug. I know of another bus nut that had the same thing happen to his 740 at Branson 2 years ago.We both use Transynd now so maybe it will not be a problem any more   thanks for the info

[DrivingMissLazy]

You guys are making me feel terrible. I run DML well over 150,000 miles over a period of 15 years and never changed the 740 fluid.

Richard.

[Geoff]

Are you sure we are talking Dexron III or do you mean Dexron-IV?  My V730 manual that is 11 years old recommends D-III or C-4.   Dexron IV is the new kid on the block.

[makemineatwostroke]

Geoff ,your right I called him he was talking about IV not III so I will change my post thank you

[bassfid]

There is no Dexron IV, no Dexron V either.  The new GM fluid is Dexron VI.   Dexron VI (SIX) is reverse compatible all the way back to the original Dexron.  Not forward compatible, however.  If your trans specifies a Dexron fluid, DO NOT use one with a LOWER number.  Higher number OK.

[makemineatwostroke]

The Dexron III(H) is referred to as Dexron IV  introduced 2 years before VI synthetic

[luvrbus]

Man, this confusing there is as many grades of Dexron as low ash oil for DD glad I went with the Transynd

[buswarrior]

Save the cash up and go Transynd.

Tranny runs cooler than on regular tranny juice, most claim 10 degrees Fahrenheit, and as long as you get it out and RUN IT periodically for a good long time to chase out the moisture....

Job is done for many years for the regular busnut.

see DML's "extended drain" experience....

happy coaching!
buswarrior

[Sammy]

I agree with BW......