Howdy Folks,
I have a 1907T hydraulic tank labeled "Monarch Dyna Jack tank" and "Only use Dexron Automatic Transmission Fluid." The fluid level has looked good since we bought in 2014. But I don't know what fluid the previous owner used. It's the typical cherry-red color.

2 Q's:
1) Should the hydraulic tank and lines be occasionally drained and refilled with new fluid as maintenance?
2) Should I buy "NAPA Premium Performance Dexron VI Automatic Transmission Fluid"....?

Lou

Lou - I'm going to say NO to BOTH!

1. As far as I know, there's no requirement to periodically drain and fill the hydraulic system. Of course, if the fluid was contaminated or showed discoloration, I'd replace it. My fluid is still the OEM fluid it had in the trailer when I bought it new in 2007.

2. Emphatic NO!!! Do not use Dexron 6 in the HiLo llift system. The original fluid was Dexron II, and Dexron II-V are compatible with the OEM fluid. Dexron 6 has been changed so that it is not acceptable. I THINK it has a completely different viscosity property.

Hope this helps and if anyone has different advice (or wants to expand on this), feel free to add your thoughts.

- Jack

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Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter, Fan-Tastic Fan, LiFePO4 battery 12V DC Electrical System, SoftStartRV mounted on A/C
2024 F150 Platinum FX4 3.5L PowerBoost SCrew

Wow, thanks for that info Jack! I won''t do a thing now!!!!!

I should add that this is not like an automatic transmission in vehicles, with a torque converter, clutch bands, and gearing, where everything is constantly under significant stress, which heats up the fluid, breaking it down and putting wear particles in it. This system just now and then uses a pump to pressurize the system, forcing the ram to move and lift the top.

About the only thing that can go wrong in a system like this is deterioration of the seals around moving parts, which could be aggravated by dirt in the fluid, so you need to keep the cap on the tank and make sure you avoid introducing any contaminants if you check the fluid level or add fluid.

A periodic "exercise" of the lift system will allow the fluid to lubricate and preserve the seals too. Hydraulic systems do not like to sit unused for long periods. I try to remember to lift my top at least every other month as a minimum. This lets you check the condition of the interior too.

- Jack

Jack,
My tank/reservoir is in the aframe along with the battery. So I can only measure the fluid level with the top up. What should the level be in this position?
John

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Jonboy
2022 Venture Sonic Lite 27 ft. 2007 Navigator
Previous 2006 25 ft Classic, and 1999 26 ft Classic

Jack,
I found my answer on a thread where Jim from Virginia stated his level is about 1” deep with top up.
John

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Jonboy
2022 Venture Sonic Lite 27 ft. 2007 Navigator
Previous 2006 25 ft Classic, and 1999 26 ft Classic