Gearbox oil change

[T540]

I am changing over from dinosaur oil to Redline Lightweight Shockproof in my Formula Ford Hewland MK8 gearbox.

Is it sufficient to remove the gears, pull the box, open the drain plug and invert it for a few days to drain the oil from the diff housing or do I have to remove a sideplate and the crownwheel assembly and thoroughly clean the interior of the casing?

Not a lot of extra work but may lead to other problems.

Thanks in advance.

[Bob Wright]

IIRC, Red line and most other gear oils are incompatible. The box would need to be completely cleaned.

[Buc01]

Did the same with my FC LD-200 gearbox. Bought the car and came with conventional gear oil.
Removed gears and cleaned them all off, drained box for several days, replaced with Red Line shock proof.
Been about 6 seasons, since then, no problems..

Aaron

[Jerry Kehoe]

Redline says the Shockproof gear oil is compatible with any synthetic or petrolium based gear oils. I have used the heavy version for as many years as they have made it with great results. Stuff sticks to everything!

[Robert J. Alder]

Easy way to drain the box:

[lucky13]

Redline says the Shockproof gear oil is compatible with any synthetic or petrolium based gear oils. I have used the heavy version for as many years as they have made it with great results. Stuff sticks to everything!

I don’t have any reason to doubt that this is true and that other synthetics are compatible as well. What I’ve always wondered, though, is that if this is true, why is there even a need to be so overly cautious about cleaning out the previous oil? If compatible is compatible, it wouldn’t matter would it?

[DaveW]

Easy way to drain the box:

Back in the day, that was the way to do a bottom end rebuild.

[Jerry Kehoe]

Saw this picture years ago of the BT 28 , I think. Loved it and certainly easier on the knees! Factory maintenance at its best

[Keith Robinson]

Back in the day, that was the way to do a bottom end rebuild.

Gotta be an Aussie Formula 3 tune-up; change the oil, fresh big end shells and it's good tor 10,000 rpm in qualifying !!

[Jim Garry]

Sorry to keep the off topic going but when I saw that photo I recalled that I did the same thing when installing a new floor on my Citation. This photo is circa 2000.

[swiftdrivr]

When I went to redline, years ago, I didn't even know to drain the whole box [IE: the half quart in the diff] I just went to refilling with redline [from Valvoline]. Never had any issues. When I started using Driven, they said I had to clean it all out, but didn't tell me to refill with 1 and a half quarts the first time, which did cause some damage. [So, don't forget that additional half quart!]

[Keith Robinson]

When I went to redline, years ago, I didn't even know to drain the whole box [IE: the half quart in the diff] I just went to refilling with redline [from Valvoline]. Never had any issues. When I started using Driven, they said I had to clean it all out, but didn't tell me to refill with 1 and a half quarts the first time, which did cause some damage. [So, don't forget that additional half quart!]

The 'half quart' stays in the diff housing because the transmission is mounted upside-down! Has anyone ever tried modifying the housing to allow the oil to flow between the diff and gearbox chambers? I've contemplated it a couple of times but yet to try drilling a hole to allow that flow.
As far as mixing oil is concerned, I've never heard of any problems with any brand name hypoid oils.

[kea]

We have drained and filled without any special exercise, on cars with Hewland Mk6-8/9, LD200, FT200 or LG500, that have been through this shop and never had a compatibility issue with Redline.