Allison Flush

Pancho · June 2, 2004

I have done the following as it pertains to the tranny:

1. Drained fluid via plug, filled w Trynsnd and new spin on filter (cleaned magnet) at 10,000;

2. Changed spin on filters about every other oil change;

3. Drained fluid via plug again at 46,000, filled w Trynsnd w new spin on filter;

4. Changed filter (spin on) last time here recently at 60,000.

I noticed the fluid is beginning to get a deeper red or brownish tint to it whereas in the past it has always been a clear red. My concern is whether it is time to take it in and have a complete flush w a replacement of the internal filter or is this normal? I have noted where many of you have done the flush yourselves. Are there any advantages to having it done professionally versus DIY? And lastly, Allison recommends changing the internal filter only if the tranny is being overhauled which I don't think I am anywhere close to needing at 60,000 especailly since I do not tow. I have been in the mountains over the past two years where the grade braking is really nice. Is it good precautionary measure to change it anyway?

Thanks in advance for any input.

snoman · June 3, 2004

A brownish tint is a sign of fluid/tranny getting too hot. I would at least freshen it if not flush it. You might look into a after market cooler for tranny too because it appears stock one is not cutting it. Be is a Allison or a Hydromatic, heat is their number one enemy!

zorrro · June 4, 2004

Pancho,

I have questions for you.

When you change your tranny fluid do you just pull the plug and replace what came out with new, change the filter, turn the key and go?

What is Trysnd?

How much fluid do you lose when you just change the filter?

Thanks, Zorrro

Pancho · June 4, 2004

Remove plug in transmission pan and drain, replace plug, remove spin on filter, clean magnet, place magnet on new filter filled w Trynsnd and top off. It takes about 7-8 quarts. When I just replace the spin on filter it doesn't lose a lot of fluid, in fact, this last time I did not add any other than what I put in the new filter which is probably about a pint, it is a pretty small filter.

Trynsnd is a special transmission fluid that Allison had Castrol develop. It is expensive, the first time I just bought several gallons, the last time I bought a five gallon bucket of the stuff. I don't think it is absolutely required as I have heard of people using Mobil 1 and others. For me, I am going to stay with what Allison recommends. As for the filters, I know more than one person that thinks I am over doing it on the filter changes but after buying 12 of them from the regional Allison distributor rather than the dealer ($7.60 versus $34.80 per filter) I can afford the added insurance.

I have decided to do a complete flush and am considering whether to take it in or do it myself.