There is a business out here called 'Gear Vendors'. They build overdrive
add-ons for just about any transmission you can imagine. RV's, motor homes,
and SUV's are their main customers. One of the basic overdrives they start
with is the Laycock 'J' type, the same one used in later Spitfires. It is
unusual to see this relatively small o/d coupled up to a large transmission.
After buying some parts, the tech guy and I started talking and the subject
of lubricants came up. His response was to give me a couple of numbers for
GM products, #12346190 and 1052271. The first is a synthetic.
When asked about the products one can find in Kragan (a local auto parts
discount store), he would not recommend any. When asked about Redline
products, OK for regular transmission use, but not for o/d use. He then went
into a long discussion about 'friction modifiers' and other additives
commonly found in most of the gear lubes. Of course, I just nodded, but
really had no clue what he was talking about. He convinced me and I just
want to pass it along. Basically, your choice in a regular transmission, be
very picky with an o/d unit, the o/d clutch is very expensive to replace.
I proceeded to replace the existing fluid with the GM 1052271 (organic) and
the o/d slides in and out very smoothly. With the old fluid, it was more of
a lurch, very positive. Initially, I preferred the lurch but have grown to
like the smooth transition.
BTW, why does the transmission fill hole have to be on the narrow side and
also have the exhaust system in the way ? You know the designers did this on
purpose ! Did Lucas have anything to do with it ? :-)
Ken C
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