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Discussion Starter · #1 ·
This truck runs very good it has 185,000 Miles owners says it has never had transmission service . He thinks you run the risk of messing up transmission , as long as fluid looks and smells good just change spin on filter every 10,000kmiles.
What are your thoughts of doing service with transyd and double flush? Also what about air intake
 

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Buy the time you see/smell burnt fluid, the damage is done.
Go ahead.
Each pan drain/refill...approx 7-8 qts of the total 17+.
I wouldn't get in a hurray to do the 2nd drain/fill, it doesn't matter if it's 5 mins or 5k miles, same dilution.

You're not putting 100% in fresh....which can cause problems in mere mortal transmissions, with a new hard bite on worn parts bathed in decayed black hyd fluid.
Not so much on the Allison....but dang! 185k down for ignorance?

Intake mod....waste of money on a Dmax, IMO. Unless you're running some serious HP.
Money better spent on a Lift Pump with aux filtration.
 

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A typical vehicle fuel supply setup will have a pump in the tank, drawing fuel and pushing it forward to the engine.

A duramax (pre 2017) doesn't have one in the tank. Instead, the CP3 pump sucks the fuel from the tank, up front and thru the fuel filter @ roughly 2"Hg vacuum.
This works well for the water separator in the fuel filter design.

But with age, fuel lines can suck flat/collapse, or kink in a bend with the vacuum draw.

A lift pump mounts back at the tank and 'lifts' the fuel up and pushes it forward to the CP3, under positive pressure, making it much less likely for a blockage to occur.

And with the added LP, you can easily add an aux FWS (water separator) for extra protection and filtration, making the one under the hood last much longer.

Or some LP kits have additional filters in their design.
You can't have too much filtration protection, especially with your 1st gen prone to wear injectors.
 
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Discussion Starter · #6 ·
No he actually changed oil and filter and fuel spin on filter every 10k miles . He just doesn鈥檛 believe in changing trans fluid . I can understand . I had a 2013 1/2 with 5.3 automatic no problems 52 k mile owned since new . I changed fluid and filter and it quit bottom line had to buy reman trans. So I am also scared about changing fluids
 

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Change the fluid. With the mileage on it do the internal filter also. If you do the hoot or double drain n flush then change the internal the 2nd go around.
 

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This truck runs very good it has 185,000 Miles owners says it has never had transmission service . He thinks you run the risk of messing up transmission , as long as fluid looks and smells good just change spin on filter every 10,000kmiles.
What are your thoughts of doing service with transyd and double flush? Also what about air intake
If changing the fluid causes failure, there is already failure. Do the double drain, do NOT do a back flush and it should all be fine. If its not fine, then the transmission was already past borrowed time.


the stock air box is more than sufficient for the truck even up to 100+ HP over stock. The factory air box is not really that much of a restriction. Now, there may be other reasons to consider an aftermarket air box like a longer service life filter, or a filter thats easier to change out, but i dont think that was the question.
 

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Discussion Starter · #10 ·
Thanks for the advise I think I will do double drain replace internal filter and spin on filter at second drain and fill . Will fill with Castro鈥檚 transynd
 

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If a fluid/filter change causes issues on a transmission, it was already going to leave you stranded in the very near future.

I used to have customers come in requesting a trans service, I always asked them why they wanted it done, and documented the answers. Most would say "it doesn't feel right", and some would then try to come after me for a reman trans if it had issues after the service. When confronted with the their statements as to why they brought it in, they shut up.

Maintain your vehicles, and most likely you won't have a problem for many years, even more so now than 40-50 years ago.
 
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