To flush or not to flush

[MoePo]

160K on the clock of my ol girl. I’ve owned it for little over a year. The transmission shifts beautifully, no leaks or foul smelling oil. It doesn’t overheat, but there’s no record of the oil ever being changed[emoji15]Thoughts?

Moe

[TonyMac]

I have never flushed, but I change my fluid regularly. Nearly 300,000 miles on a 95 K2500 Suburban and it's still going strong.

[Excesses]

We’re preventative maintenance people. When we got our 2000 as the third owners, we went through the receipts that we could find. Preferring to nip any potential problems in the bud, we flushed and changed the transmission filter. They found that the wrong pan had been put on at some point in the past, and put on incorrectly to boot. Probably saved ourselves hundred$ if not thousand$ including breakdown costs etc.
We also changed out the rad hoses, heater hoses, shocks, brakes, tires (aged out and worn) and numerous other things.
Starting at “zero” unknown is peace of mind for us...
We also created a spreadsheet of all available receipts and entered them chronologically and now we can anticipate future maintenance requirements with some degree of confidence.

Our advice would be to spend small now instead of spending large later. Knowing what you have gives you great peace of mind. Maintenance documentation also slightly adds to resale value down the road.

Cheers! Safe travels!

DJ & BJ

[Piker]

Originally Posted by USMC_1345

160K on the clock of my ol girl. I’ve owned it for little over a year. The transmission shifts beautifully, no leaks or foul smelling oil. It doesn’t overheat, but there’s no record of the oil ever being changed[emoji15]Thoughts?

Moe

A good idea would be to pull a sample and have it analyzed by someone like blackstone labs. For $30 they can tell you exactly what shape your fluid is in, and maybe even what kind it is (regular dexron vs a TES-295 fluid like Transynd). There's also a guy in the Allison Transmission forum here at IRV2 who can analyze your fluid. Here is his thread... he can answer lots of questions. http://www.irv2.com/forums/f125/form...tml#post830153


After it's analyzed you will be able to tell whether it needs replaced or not... if it's still good, you should probably figure on changing the filters regardless, that is if you have no service records from the previous owner as to when that may have been done.

We did a double drain and refill on our MD3060 allison over the course of a couple years using a synthetic TES-295 fluid. Takes 18 quarts to drain and refill, but there is still something like 10 quarts left in the torque converter. Doing this twice gets you to 88% synthetic oil... Once you have the good fluid in the tranny, you only need to change the filters regularly and top off the oil for something like 150,000 miles or more on a 3000 series transmission. It's a few hundred dollars for one oil change if you do it yourself... I don't know what it would cost to have someone do it for you, but it's a good investment.

I don't believe Allison recommends any type of "flush" other than a double drain and refill.



Just my $.02


cheers