How Low is too Low? Cruising at Low RPM

Ribbedroof

Ribbedroof

Royal Smart Person
Supporting Member
Jan 4, 2009
2,481
2,107
113
Wellston, OK
#21
, you need to lock up the torque converter or risk burning the trans up. the way it was explained to me is, the torque converter generates heats when not locked up. from there, the fluid is sent to the trans cooler and back to the trans to lubricate its internals. if the lock up is not used, the fluid is not sufficiently cooled and, over time, will destroy the trans.
Isn't that the way every pre-lockup AT works?

Ran a 200C for 6 years and over 40000 miles with no functioning lockup...which is more than many TH200s lasted when new.
 
Longroof79

Longroof79

Geezer
Oct 14, 2008
9,731
5,427
113
Gainesville, Fl
#22
Why not consider using a 700R4 instead of the 4L80E?
 
Firetruck1

Firetruck1

Apprentice
Nov 1, 2017
68
108
18
#23
Jack, while the 700 will improve acceleration, it will eventually die behind a big block, Additionally, each has such a similar overdrive ratio that neither does a better job addressing the initial question wich was what to do with his land speed record rear gear ratio.
 
TURNA

TURNA

Geezer
Jul 24, 2009
6,326
8,011
113
Socialist NY
#24
I have a Freddie Brown 700 trans.

Was in my Malibu for years and now sits in my friends 68 Chevelle with a big block.

That thing has been going strong for 20 years of beating on it like a red headed stepchild.
 
RGBody87

RGBody87

Greasemonkey
Jan 7, 2018
139
31
28
#25
I have a Freddie Brown 700 trans.

Was in my Malibu for years and now sits in my friends 68 Chevelle with a big block.

That thing has been going strong for 20 years of beating on it like a red headed stepchild.
Turna,

I have a Freddie Brown Turbo 400 I just took out of my 87 Monte, T56 Magnum is going in this week to replace it. Hopefully 3.70 gears wont be too brutal.. but I'm sure I'll be switching to 4.11's in a year or two. Glad your transmission has been holding strong. I hear great things, and mine is like new... but I am going to post it up here and try to sell it.

Ryan
 
RGBody87

RGBody87

Greasemonkey
Jan 7, 2018
139
31
28
#26
I used the Tremec calculator for manual transmissions, I'll be around 1500 to 1800 RPM for cruising speed which should be like 65-70. I'll probably have to drop to 5th gear to function at 55 mph or less. tri-five's website has a good gear calculator you can use. But I think 1,500 for cruising should be fine. I wouldn't go lower though.
 

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