RE: Allison 3000 series trans. Models B300, B400 & T
milford57 - 12/1/2009 2:14 PM
Has anyone experienced water intrusion and or damage to their Allison 3000 series Trans. Models B300, B400 & T? If so - what seemed to be the problem and how did you fix it?
Are you experiencing water in the trans, or engine coolant? The two have very different causes and remedies. My experience is the same as Len's. Most of the time, it's a problem in the cooler in which anti-freeze is bleeding over from the engine cooling system into the trans.
Glycol attacks the bonding of the friction material in the transmission clutch plates that holds the friction material to the steel core. Once glycol enters the trans, the best remedy is to fix the leak, then have all the friction clutch plates, seals and gaskets in the trans replaced.
I did see one tour coach in which the rear restroom had a leak and poured water over the transmission breather and into the trans.
There have been a few vehicles made where the top of the dipstick tube is in a place which exposes this area to melting snow, rain, etc. If the dipstick is loose, water gets in.
Water or engine coolant in the trans will turn the normally red trans fluid a pinkish color once enough gets in there.
There are test kits that will detect glycol and help diagnose the difference between water intrusion and engine coolant.
I hope this helps.