metric allison

[MyPrevost]

I crawled under the coach to drain the transmission so I could fill it up with Transynd. The pan drain plug was no problem; the 3/8 drive worked perfectly. I took a 9/16 and a 5/8 socket with me, anticipating a filter change.

Nope. You guessed it—15mm!

I can get under the coach and back out just fine; it’s just my fat butt and belly that make it a bit of a challenge!

[MyPrevost]

I crawled under the coach to drain the transmission so I could fill it up with Transynd. The pan drain plug was no problem; the 3/8 drive worked perfectly. I took a 9/16 and a 5/8 socket with me, anticipating a filter change.

Nope. You guessed it—15mm!

I can get under the coach and back out just fine; it’s just my fat butt and belly that make it a bit of a challenge!

POOTIE, quick, bring me a 15mm 3/8″ drive socket.

[MyPrevost]

Jim, are you changing your filters as well, I believe you need to fill them before installing.

[MyPrevost]

I didn’t change the filters since they were new last August; I just loosened the bolts to the filters for a more complete drain.

It’s just another aggravation of having dealerships do work for you. I had asked them to install Transynd during the PDI, but they didn’t. I even offered to pay for the Transynd instead of their Dexron. It gets old!

My plan is to change the filters sometime next year, followed by another fluid change in about a year. That should pretty much complete the conversion. In the Allison 4060 application, you can lose almost two gallons with a filter change, so I figure periodic filter changes will handle any residual Dexron.

Just for reference, I let it drain for two days. You’d be surprised how much more fluid comes out after the initial dump.

Anyway, I was surprised to find that the transmission uses metric bolts. I’ll definitely add a 15mm socket to my carry list!

[MyPrevost]

You can’t pre-fill the filters on an Allison six-speed because they’re a pleated type sitting on a plate, and there are two filters involved.

One thing to note is that the fluid in the intercooler cannot be removed unless you go through some serious disassembly.

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