For the Duramax / Allison Folks

[RMccord]

I just got some information from a Duramax Allison transmission specialist. Has his own tranny shop and very in with GM.
The normal trans fluid in our Allisons is Dexron 3. Allison only recommends 2 Dexron 3 and Transynd (synthetic). Per Mike at Inglewood Transmissions the benefits of the Transynd are extended service intervals, better clutch adhesion,better tollerance to overheating, cooler running temps, Allison insists that it be used if under extended warranty. Per him Allison ships all their transmissions with Transynd in them. OEM Allison transmissions are filled by the Factory and in most cases have Dexron 3 in them.
Changing to the Transynd will change the shift points a bit, I think it extends them, cooler tranny temps, and less frequent changes required.
I am going to go to this at my next oil change at 10K. It is a bit pricy but I feel in my lengthy conversation with him and another Allison service center that it makes sense.
if anyone is using it already what has your experiences been with it.

[8.1al]

I have been using Transynd in my Allison since the first oil change at 25,000. Although it does run a little cooler I managed to burn the fluid coming out the east of Yellowstone on Hwy 14. This is a long 10% grade and even though the trans. temp gauge never got over 205-210 it did smell a little so I changed it. Everything I have read on synthetics confirm that they definitely protect your vehicle better than dino oil.

[OntMont]

I took mine into an Allison shop for the 120.000 km oil change and they recommended Transynd. I think it may shift a little smoother, but it was never rough anyway, so it is hard to tell for sure. It cost about US$125 for the oil. The two filters are extra, but Allison charges less for them than.

[Bill and Ann]

John: (OntMont) Did they install the Transynd as standard or was it offered as an extra. I got mine changed at the same place you did the next day and I am not sure what they put in.

[Bill Hill]

Bob,
Was that Inglewood Transmissions in Inglewood CA? We live in San Pedro so it's not that far to go, and I'm due for my 25K transmission oil change. If not, is Transynd something that should be available at my Chevy dealer or oil change place?

[RMccord]

First the owner is Mike L and it is near LAX. Very close to 405 and Century Blvd. Here is the phone number 310-674-4400. He is a advocate of Transynd but most of the work he does no one pays the extra for it. It can be purchased from local Allison service centers. It is pricy. Here in Ventura it is about $37 a gallon. But I think the additional money about $100 to 125 per tranny oil change is worth the piece of mind. Also my understanding is that Allison won't support extended warranties on their transmissions if it isn't used. Per the local service center there is a trace element in it that they check for to insure it is Transynd in the tranny. This is not saying that your GM warranty 36000 miles requires it. Dexron 3 or Transynd would satisfy both as I understand it. Mike is also the fellow that developed a drop in tranny replacement cooler for the Duramax. It will reduce temps by about 20-25 degrees regardless of the choice of fluid. It runs $450. However he will install it free if you drop unit by there. I am going to in next several weeks.
The factory cooler has something like 9-12 plates if I am correct his has 23. It will not affect warranty per Mike either. It is a very easy install and can be accomplished by anyone in 30 minutes. Reguires no cutting etc.
He doesn't have a web site but here is a thread to the Diesel Forum discussing his development of it.
This one is some reactions of those who have installed it
http://www.dieselplace.com/forum/sho...=tranny+cooler
This one is on his development history
http://www.dieselplace.com/forum/sho...=tranny+cooler
Hope this helps.
He is super friendly and more than willing to talk to you about your Allison. He loves them. His only complaint about them is that they are too smart.
Also did you know that your Allison has a 6th gear. Yep GM did not activate it but it will be on the 06 models and there is a good chance that at some point we may be able to get our in play also. DOn't know what it would cost and I am not sure it is going to benefit us much as it is another overdrive gear. There is discussion on this forum about that as well. This forum is a huge source of info on Duramax's
Thanks

[8.1al]

Way back in 01 when the Allison was first put in the GM trucks I heard that the 6th gear was there in the tranny and that all it took was a software change. I asked an Allison tech about it and couldn't get a straight answer from him. If this is true though we may already have 6 speeds and don't know it. Incidentally, I paid $27 a gallon for Transynd at the Allison dealer in Sioux City, Ia and they get $180 for an oil and filter change with synthetic. No thanks,did it myself

[OntMont]

Bill, (of Bill and Ann),

The tech. asked me first if I wanted synthetic, although he did it in a way that suggested that it was the right way to go. The Service Advisor fellow confirmed it with me as well. Price is probably the best indicator, if you paid somewhere around $125 for the fluid, it should be Transynd.

I went for it mostly because of the fact that we are pulling a pretty good load most of the time.

[Bill and Ann]

Thanks John: I will check my bill and see what they put in. I don't remember him asking me re the synthetic.

[Bill Hill]

Bob,
Thanks for the info, I'm going to call them today. If its the shop I think it is, they rebuilt the tranny in a Mercedes diesel wagon I had years ago and did good work.