Allison Fluid Change

[Dr.Jones]

Just bought a used 01 silverdo with 8.1 / allison combo. Love the truck. When towing my boat up in the mountains my tranny temp gets up to 220+and starts to spit a little fluid out of a top vent on the transmission? With no load its fine. I did read a post about to much tranny fluid in the transmission. The dipstick shows above the top range at temp. and I bet the tranny fluid hasn't been changed in who knows how long. I'll change the filter and fluid today and just fill it to the bottom of the acceptable range on the dip stick and see how she does. Any input would be great, thanks

[sillyazz]

Just bought a used 01 silverdo with 8.1 / allison combo. Love the truck. When towing my boat up in the mountains my tranny temp gets up to 220+and starts to spit a little fluid out of a top vent on the transmission? With no load its fine. I did read a post about to much tranny fluid in the transmission. The dipstick shows above the top range at temp. and I bet the tranny fluid hasn't been changed in who knows how long. I'll change the filter and fluid today and just fill it to the bottom of the acceptable range on the dip stick and see how she does. Any input would be great, thanks

Should have 2 filters a screw on type (looks like an oil filter) and one on the inside when you drop the pan. If its overfull and gets hot its going to spit it out.

[Dr.Jones]

Thanks for the reply Sillyazz. This is what I found out. I bought a new screw in filter at the stealership for $30.00 and was told by the service tech after draing old tranny fluid from the transmission pan drain, replace the filter and fill with 8 qt. Dextron III. I stopped at checker on the way home bought 8 qt. tranny fluid and asked the counter guy the same question. He looked it up and his computer said 7.5 qts. with filter change. And he has filters for allison transmissions in stock for $20.00 each. I remember reading a post on here weeks ago (the one I can't find now) and this guy was saying fill the allison tranny just enough to pass the lower index mark (when engine is at temp) on the hot range. So I did the dirty and refilled with 6.5 qt. drove around, checked. And I'm exactly right in the center of the hot range. Drove, checked,drove,checked.I'ts good.BTW. the old tranny fluid wasn't bad looking. But the remnents that were in the old filter were brown and soupy. I bought this truck from a guy that didn't maintain this truck.So I think I had 3 problems. 1. filter and fluid needed changed2. transmission was overfull3. mountain drivingI'm going though this truck with a fine tooth comb now. This truck lucked out.Oh, and I just found a rub hole in the transfer case.

[merlin5577]

Just bought a used 01 silverdo with 8.1 / allison combo. Love the truck. When towing my boat up in the mountains my tranny temp gets up to 220+and starts to spit a little fluid out of a top vent on the transmission? With no load its fine. I did read a post about to much tranny fluid in the transmission. The dipstick shows above the top range at temp. and I bet the tranny fluid hasn't been changed in who knows how long. I'll change the filter and fluid today and just fill it to the bottom of the acceptable range on the dip stick and see how she does. Any input would be great, thanks

 

 

Do not drop the pan and replace the internal filter on an allison transmission. Just drain, refill and change the spin on filter only. http://www.allisontransmission.com/service...p?CategoryID=11 http://www.allisontransmission.com/service...sp?CategoryID=3

[minibike132]

The in pan filter is intended to be changed only at overhaul but I don't think changing will cause any problems it just isn't necessary.

[Dr.Jones]

Thanks for the replies, I did read all the information on allisons website before I did anything. And just did the external filter and fluid change.

 

The tranny shifts fine.