Auto Not downshifting on 1995 Z28
Frank M. Barone
I just got a 95 Z28 with the auto transmission. One thing I noticed is
that when your going about 20mph and punch it, the transmission does not
drop to first. Since there is no position for 1st(only 2nd), you can not
do this manually. So the
car seems slow from 20mph. If you start from 0-5mph and nail it, the
transmission does not shift to second until about 45-50mph.
Is this operation normal?
Rob Candau
I would suggest checking the adjustment on your TV cable. The one that
runs from your throttle linkage back to the tranny it may be too loose
and not pulling the tranny down into the proper gear range. If that's
ok next would be to check out the transmission itself.
--
Rob Candau Internet: can...@austin.ibm.com
Project Lead AIX Austin Helpdesk ISSC South
** Opinions expressed are my own......NOT my employers **
TBird4Play
>I just got a 95 Z28 with the auto transmission. One thing I noticed is
>that when your going about 20mph and punch it, the transmission does not
>drop to first. Since there is no position for 1st(only 2nd), you can not
>do this manually. So the
>car seems slow from 20mph. If you start from 0-5mph and nail it, the
>transmission does not shift to second until about 45-50mph.
> Is this operation normal?
Are you sure you're talking about a 1995 Z28? I have a 1995 Z28 and it
_does_ have a position for 1st on the shift.
Not only that, if I punch it at 20MPH, mine downshifts into first, and
breaks the back tires loose most of the times I do it. It also barks them
when I shift from 1 to 2.
My brother's 1994 Z28 does the same thing and also has a 1st position.
I don't know what gives here. Did they change something?
Questions:
Do you have the Performance Axle Ratio???
Do you have a 150MPH Speedo?
Do you have the 245/50ZR16 tires???
__________________
\hunderbird
Strap yourselves in. This flight is gonna suck, and we don't serve
peanuts!
SEM 7041
I have a '95 Z ..... and mine does NOT have the 1 gear selectionposition
either.....
only 2/D/OD......
Curious to why some do ...... and some don't
Steve McCorry
sem...@aol.com
Frank M. Barone
Yes, I have a 150mph speedo
No I don't have a performance axle
No I don't have Z-rated tires
TBird4Play (tbird...@aol.com) wrote:
: In article <fmbDsM...@netcom.com>, f...@netcom.com (Frank M. Barone)
Will H.
According to the F-body home page FAQ (http://wj.net/f-body/), it
has something to do with Automatics with the 2.73 rear that can't
pass Federal noise pollution test in 1st gear.
They also have a suggested solution for that problem. Just trim off
the plastic stop on the right side of the notched selector ramp.
Will
ME
In article <4pijg8$4...@newsbf02.news.aol.com>, sem...@aol.com says...
>
>I have a '95 Z ..... and mine does NOT have the 1 gear selectionposition
>either.....
>
>only 2/D/OD......
>
>Curious to why some do ...... and some don't
You most likely have a 2.73 RGR. Put the shifter in 2nd, pull the shifter
cover off, find the the plastic stop and cut. Now you can 'Whip Ass' as a
'Stang sneaks up on you around 40mph. Down shift to that new 1 gear position
and then be ready to quickly shift to second before the limiter kicks in.
If you want some more excitement, add a Precision Torque Converter, it has a
0 pump (approx 3200 stall) and is a little loose (and expensive ~$800) but hey,
when you want to run it will definitely go. On a full run after you hit second
gear the rpm's stay around 45-5000 so you are always producing full power.
Traction is a real concern. My 26X9.5-16 MT SS Pro's can't take a full
throttle launch, though 60ft time is around 1.7-1.8 with feathering (if you do
decide to torque brake then you are looking at fish-tailing the first 1/8th).
The GSC's will break loose any time you go WOT in 1st (45 or less). Just in
case you think 3200 stall is too high for street driving, it isn't. If you
don't punch it every time you go, then the converter will feel basically stock
with no more slippage than 500 rpms over stock.
PS. When the car was bone stock, this '96 2.73-Auto could out run a new Cobra
and did and I've never been beat by a 5.0 (My little bro has a '91 5.0 and he
loves the way my Z and our '95 ImpalaSS runs). The car even beat (maybe 6- car
lengths requires the word WHIPPED) a 6 sp Z after only restoring 1st gear.
Granted it was a 30 punch and probably a bad driver in the other car but I won
and I was manually shifting too :)
Oh yeah mine is a 96Z28 but the fix works the same in '95s
Craig Luna
Markus Strobl
Frank M. Barone wrote:
>
> I just got a 95 Z28 with the auto transmission. One thing I noticed is
> that when your going about 20mph and punch it, the transmission does not
> drop to first. Since there is no position for 1st(only 2nd), you can not
> do this manually. So the
> car seems slow from 20mph. If you start from 0-5mph and nail it, the
> transmission does not shift to second until about 45-50mph.
> Is this operation normal?
I don't know about your downshift problem, but if you look in the f-body
FAq at http://wj.net/f-body you will find instructions on how to modify
the shifter so that you can select 1st gear. I'm told it's pretty easy,
but I have the stick-shift so I haven't done it.
--
Markus Strobl 96 Z28 6M Black/grph. Borla, !CAGS, PEG2, QLC
Dallas, Texas 1LE driveshaft, Honker, T-tops, CD, leather
F-member 9/93 13.83 @100.41 Best mph 101.7 - 27.5mpg @85mph
John M. Baltz
SEM 7041 wrote:
>
> I have a '95 Z ..... and mine does NOT have the 1 gear selectionposition
> either.....
>
> only 2/D/OD......
>
> Curious to why some do ...... and some don't
>
> sem...@aol.com
If you got the performance axle option you get to select
1st. This has to do with passing a noise test. With
the perf axle the trans won't downshift to 1st at the
speed the test is conducted (don't remember what that is
think it's arounf 25MPH). If you don't have the perf axle
the you can downshift to 1st at the test speed so GM blocked
it at the gear selector. There is a plastic stop that can
be removed (cut off) which will allow you to get to 1st.
--
John M. Baltz (jmb...@vnet.ibm.com)
Snake
>I just got a 95 Z28 with the auto transmission. One thing I noticed is
>that when your going about 20mph and punch it, the transmission does not
>drop to first. Since there is no position for 1st(only 2nd), you can not
>do this manually. So the
>car seems slow from 20mph. If you start from 0-5mph and nail it, the
>transmission does not shift to second until about 45-50mph.
> Is this operation normal?
>: Are you sure you're talking about a 1995 Z28? I have a 1995 Z28 and it
>: _does_ have a position for 1st on the shift.
>: Not only that, if I punch it at 20MPH, mine downshifts into first, and
>: breaks the back tires loose most of the times I do it. It also barks them
>: when I shift from 1 to 2.
>: My brother's 1994 Z28 does the same thing and also has a 1st position.
I read somewhere (exactly where escapes me now) that 2.73 geared Z's
and Formulas DO NOT have a manually selectable 1st gear in order to
pass one of the EPA's tests. The test has something to do with
measuring decibel level at a certain speed with the car's transmision
positioned in the lowest selectable gear. The 3.42 geared cars will
not go into first at this speed, hence they left the selector on the
shifter. The 2.73 geared cars, due to the taller gear, CAN indeed go
this speed the EPA uses in 1st gear, so they had to remove that
position to make the car compliant. I'll see if I can dig up that
article where I found this and post it. There is also an easy "fix"
to make first gear selectable, even though there appears not to be a
position for it on the shifter. I believe this started on '94 models,
but again, I'm not totally sure on the specifics.
George
1993 Formula A4
Snake
sn...@jaxnet.com (Snake) wrote:
>George
>1993 Formula A4
Here's what I found in the F-body FAQ located at www.wj.net/f-body/
Q: Why is there no selectable 1st gear on some of the Z28s with the
4L60E automatic transmission?
A: According to a tech on 1-800 Chevy number, the Z28s with automatic
trannys and the 2.73 rear can't select 1st gear
because in order to pass the Federal noise pollution tests, Chevy had
to lock out selectable 1st gear. It has something to do
with downshifting into the lowest selectable gear at some speed (?) as
the car goes through the sound traps. With the 3.23
rear end, the required speed is high enough that the tranny won't
allow a downshift all the way to first. With the 2.73 gears,
the car will downshift all the way to 1st increasing engine (exhaust)
noise.
To cure the problem, lift off shifter cover, locate plastic (nylon?)
stop at the right side of the notched selector ramp, use a
hacksaw blade to remove the offending (square) stop. Once gone,
THERE'S FIRST.
TBird4Play
In article <fmbDsr...@netcom.com>, f...@netcom.com (Frank M. Barone)
writes:
>Yes, I have a 150mph speedo
>No I don't have a performance axle
>No I don't have Z-rated tires
There's a clue.
I have the 150MPH Speedo (which I thought you only get if you get the
Z-rated tires)
I have the Performance Axle
I have the Z-rated tires
So, it's either the Axle or the tires that could be the option you need to
get a "1" selection?
TBird4Play
Everyone keeps recommending a high-stall torque converter for better
performance. I have a couple of questions:
1) Why is it that a higher stall speed gives the higher performance in the
first place?
2) Does GM make a high-stall converter which will replace the one in my
1995 Z28? I have a friend who will install it for me, so labor isn't a
concern. How much does the converter itself cost? Anyone havea part #?
3) Will it void my warrantee? Or do I have to have Chevrolet install it to
keep the warrantee safe? Will an aftermarket converter void the warrantee?
Thanks!
DZimmer363
i might spell this wrong but check your mogulater valve in the trany. new
cars it can stick!also check back with me my freind is a pro with the lt1
and ru4 tranys dzimmer383