I'm thinking of replacing my TH350 with a 700R4 to get OD. Quick search on
the web brings up a lot of so called heavy duty units. Are they any good?
What problems will I run into? Will a 700R4 hold up or is there a better
The car is not a Vette, it's a 73 Nova with a mild 454. You guys are the
ones I trust:)
73 Nova, 454, TH350, 4.89 9" Ford. 12.00 @ 113 MPH street car.
700R4 and 4L60 are two names for the same thing. A 4L60E is also the
same, but computer controlled (sorry Troy, it's not any stronger).
Pre 1988 700R4's weren't perfected yet. Avoid them. So, 1988 and up
700R4/4L60 is what you're looking for. There were a number of
different tailhousing lengths. Avoid a Corvette model as it probably
doesn't have normal rear mount.
It should be a bolt in (SB and BB are the same bell housing, right?).
Models with a mechanical speedometer drive should hook right up to the
speedo cable. You'll need a Throttle Valve cable bracket (very
different than your TH350 kickdown cable), a TCC lockup controller, a
shorter driveshaft, and probably a new transmission crossmember. The
shifter will work but won't reach down to 1st. Be very careful with
the throttle valve operation and adjustment. You can toast a
perfectly good transmission in one launch if it's wrong.
Summit Racing sells all these parts. They'll also have new 700R4's
that are built to take the abuse of your 454 Nova. I'd be hesitant to
bolt up any junk yard transmission behind even a mild big block.
Not only will you get a nice overdrive that sips gas, but the 700R4
has a lower first for better launches.
Well, sure, but I don't know much about them nor have I ever seen
one. Performance catalogs only seem to list parts for the TH350,
TH400, and 4L60/TH700R4.
Strange: I brought my '99 Jeep Grand Cherokee to the dealer today to
have the transmission computer reprogrammed. It was a 4-speed
automatic when I drove it in, and a 5-speed automatic when I drove it
out! Hard to believe! The '01+ models are 5-speed and the only
difference was the programming.
On Thu, 31 Jul 2008 12:45:42 -0700 (PDT), The Reverend Natural Light
There must be more to the jeep story... there is no such thing as a
hidden electronic "gear"... The programming might have changed when
the TCC engaged.. The mechanical parts have to exist in the trans to
support 5 speeds.
Some places are selling something called a 4L85E as a HD trans. You
have to use a controller on these transmissions unless you have the
engine harness and PCM out of a matching vehicle.
It's hard to believe, but a flash update really did add a fifth gear!
"NOTE: THIS REVISION .... ADDS A FINAL GEAR RATIO TO THE **1999 AND
2000 MY** GRAND CHEROKEE TRANSMISSION ONLY."
The 1999 and 2000 are 4 speeds. The 2001-2004 are 5 speeds. They're
mechanically identical. The only difference is the programming.
Fifth just never engages on the older ones. Only Chrysler could say
It didn't ADD it, it ENABLED it, Elbert was spot on. Just a guess but
perhaps the earlier engines were having trouble pulling the taller
gearing so it was disabled to prevent warranty issues from lugging and
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