Assessing a used 3500 8.1

[maxpower29]

Alright will do. Can't wait to get it and I hope it fits in my garage

[maxpower29]

Any suggestion with the tranny fluid though? Should I flush or just replace? Read that trasynd is the best fluid, hope I can get it here

[mike221]

Drain and fill. The truck will have an Allison 1000, so just drain, and replace the spin-on filter. Check for oil consumption, my 8.1 drinks oil like its going out of style

 

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[mike221]

Also, dmaxstore.com sells trans service kits with the amount of transynd and the filter you will need. you can get an Allison OE deep pan with the kit too if you want. Brings fluid capacity up to 2.5 gallons, they use that pan on medium duty trucks

 

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[Chris]

Different strokes on the fluid. I like Amsoil. It is what I run, but any synthetic that meets or exceeds the specifications set forth by GM and Allison

[maxpower29]

Thanks guys. I expect it to eat oil. Will only use it a few thousand kms a year so it shouldn't be a problem

[mike221]

Different strokes on the fluid. I like Amsoil. It is what I run, but any synthetic that meets or exceeds the specifications set forth by GM and Allison

It'll run any that meet the standards, but the 1000 loves transynd, seeing as the fluid was designed by allison for its transmissions. Transynd will run much better than a Dexron fluid

 

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[maxpower29]

Keep forgetting to ask but would a tune or chip be something worth getting for me as well mpg wise? I don't want any more power

[Formulabruce]

Superchips did make a programer that set your trans shift points DOWN some, making the transmission shift up at a lower speed, it was called a Mileage XS Super tuner. It is a plug in, adjust and remove. I do NOT know if one was made for the Allison.. Other than that , your type of tire and brand can be huge. From my experience with 3/4 and 1 ton 2wd truucks I have found that Michelin has the lowest rolling resistance and best ride, giving better economy. Your truck probably has a 373 rear, vs the 410 a 6 liter will have. check glove box code for it ( will say GTx.. , like GT5, GT6 etc) , look for a G80 as well ( limited slip) .

[maxpower29]

Superchips did make a programer that set your trans shift points DOWN some, making the transmission shift up at a lower speed, it was called a Mileage XS Super tuner. It is a plug in, adjust and remove. I do NOT know if one was made for the Allison.. Other than that , your type of tire and brand can be huge. From my experience with 3/4 and 1 ton 2wd truucks I have found that Michelin has the lowest rolling resistance and best ride, giving better economy. Your truck probably has a 373 rear, vs the 410 a 6 liter will have. check glove box code for it ( will say GTx.. , like GT5, GT6 etc) , look for a G80 as well ( limited slip) .

Thanks, was searching a bit online and I thought it said it has the 410s but i really hope your right and its 373. My Tacoma 4 cylinder has 410s though and its not too bad on the highway so if I can have a light foot like usual I hope I can keep it above 10 mpg. Im not overly worried but 11-12 would be nice

[kstruckcountry]

Keep forgetting to ask but would a tune or chip be something worth getting for me as well mpg wise? I don't want any more power

Nothing is going to help your mileage... That's a big block for you.

 

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[maxpower29]

Ya thats what Im thinking. Shouldnt be too bad with the 2wd I hope and the usual Im towing is a 3500lb loaded camper and an 860 lb atv which together should be nothing, I think it will be fine. When I load up the camper and tow with my Tacoma I only get 11-13mpg anyways and thats working the 5 speed like Im an olympic rower so I think I'll be happy

[kstruckcountry]

The biggest help will be staying light on the gas when you're not towing, and it sounds like you're well aware of that.

 

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[maxpower29]

yup, i dont imagine it will be moving much when not towing anyways

[maxpower29]

Finally picked it up today, and wow I love this truck. So comfortable to drive and very very tight and firm. Also very surprised with the gas mileage after doing a lot of reading. I was expecting to see around 10 mpg and was hoping to somehow get it around 11-12 to feel a little better about it. Drove it home 420 kms over 4 hours with a little 50km/h, little 80 km/s, a lot of 100 km/h, and a lot of 110 km/h +. It was VERY windy, some rain and tiny bit of snow falling here and there, and overall cold, also adding the fact we are into winter gas formulas right now which usually hits the gas mileage a bit. I ended up running 13.8 mpg and felt like I could have done a lot better if it were spring or summer. Super happy with that and just assumed I had the 3.73 gears seeing decent mpg, but I opened the dash and looked at the msrp paper from 2003 and it says it has 4.10s! Another thing to be happy about.

Truck is beast and will do exactly what I want it to do with ease Im sure. Everything works great, feels smooth, and the only thing I was not liking when I tested it before was the squeal from the belt but he has it replaced and it was quite today.

Love it!