Great tech info and efforts on your 722.6.
It's also called a 5-Gtronic and AKA W5J400
Used jointly in many MB & Chrysler rear drive vehicles, Dodge Charger, Challenger, Grand Cherokee, and on and on.
On fluids, consider that using the 236.10 spec fluids versus the later, slipperier 236.12 or .14 that were designed for the 7 & 9 speed boxes, these latter ones are LV fluids.
I would suggest your box MAY be happier with the original spec.
I def agree with using the Lucas, if you will employ the Valvoine Max Life as it's an .12 / .14 slipperier fluid.
So, how do I find the earlier spec 236.10 ?
I could source Shell 3403 but soooo much easier to just get any brand of ATF+4 fluid for Chrylser Mopar it still has all the fluid specs for these awesome 5 speed boxes.
Anyhow, just an idea, and it's Full synthetic and you can get it in Gallon jugs at O'reilly's for around $5 per quart, $20 gallon.
Or pay $6.50 quart for the Valvoline ATF+4.
It's a licensed Chrylser fluid made by 50 vendors worldwide. Given such wide distribution, the price is reasonable. Heck for the super budget sensitive, it's $ 4.27 a quart at WalMart.
Desgined in the late 90's when 'DamlierChrysler' was a thing - ergo the crossover of fluid spec.
Since discovering this, I do annual 1/2 fluid drops, every 2 years drop pan change filter.
Boxes run perfect, no hiccups & no pan junk.
I feel guilty as the fluid coming out looks quite pristine.
just an FWIW...
David in East Texas
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