sierrastarr1@sbcglobal.net

First thank you all for your responses so far, I appreciate them all. I did use a synthetic that is on Allison's approved list. Transyd is not the only synthetic transmission oil on their list....there are several. So I rule that out as the cause. I will be talking to Allison come Monday morning and am interested in hearing from others with thoughts, experiences, expertise etc.. Thank you all again Phil

Last Fall after having a new transmission seal and new brake shoes put on the pilot shaft (1999 Beaver Patriot, Cat 3126B) I converted to synthetic transmission fluid after checking with the folks at Allison headquarters. Fast forward a few months and my parking brake is soaked in fluid and nearly useless again. I checked in with installing truck/motorhome repair shop that did the work and the foreman checked in with Allison and they told him not only is there NOT a seal that will hold up to the synthetic but I will develop other leaks as well!! What the Hay???? As mentioned I spoke with Allison BEFORE making the change and got the OK from them. I must say the transmission runs much cooler with the synthetic, which is great, but what a mess now!Repair shop foreman has a buddy that has worked at local Allison certified repair shop and is waiting to hear back believing there nay be an aftermarket seal that will work. Anyone out there have any information and or HELP for this situation? I can't be the only one that's run into this. Thanks Phil 1999 Beaver Patriot Ticonderoga in Beautiful shape.