trans leak

[Diesel_D]

After pulling a heavy load today i got to my destination and noticed some trans fluid on the ground. After further inspection it appears to be coming out the side of the trans what looks like a pressure relief valve or something on the drivers side of the trans. Is this a normal or do i have a problem. Truck is a 2002 dmax allison. Estimating load about 10k and pulled about 30 miles. Trans temp was around 200. return trip with just a 4k trailer didn't seem to leak any more. thanks

[Diesel_D]

ok further investigation..It appears to be coming from the breather on top of the trans. also did some research and my skidsteer weighs about #8300 not counting a 12k dump trailer ( not sure what it weighs) so i was real heavy.

[More Power]

How's the fluid level, before/after the leak?

As I recall, GM offered a revised vented trans dipstick pipe a few years back to help resolve some sort of leak problem. Mine hasn't leaked with the old style pipes, so I've not looked into it further. Although, the Allisons I've been involved with have displayed the torque converter "drain-back" phenomenon we here about occasionally when the truck sits for at least several days to a couple weeks. Over time, the ATF in the torque converter will drain back into the trans pan, raising the fluid level, which can then leak out - usually at the dipstick pipe lip-seal where it enters the transmission.

Jim

[DmaxMaverick]

If it only spit a little bit when you worked it hard, it's probably excess from thermal expansion. The excess fluid will vent. This normally happens when the tranny fluid level is checked/filled when the fluid is less than hot, or less than as hot as it will get when worked under heavier load. If it doesn't keep leaking, I wouldn't worry about it.

[Diesel_D]

thanks for the replies. I think that was the problem, last time I changed it I filled it with cold fluid and have not worked it that hard until today. I think it was just puking out the vent on top of the trans.