74 VETTE WITH 350 zz4 ENGINE 62mph THE rpm's at 3,000 and screaming (red lie starts at 5,000) what is my gear ratio and what should it be for highway driving

2wd right?(1995 is GEN1, T100)
auto trans or manual trans no told and both are told.
we can't guess drivelines blind,so tell it.?
2.7L, 3.0L and 3.4L engine options new.
toss coin land on A/T box. (most common )
the TCM decides all this not you,
the Tcm/Pcm/or TCU are all transmission brains , the PCM does engine too, and tells the TCM speed, and engine loads (hills etc)
rpm based on all that and gear ratio, in the transmission, 1:1 or overdrive. too and the axle ratio and tire size (circumference)
are tires stock, or low rider tiny.???????
5 speed manual or 4speed automatic and 4 engine choices not one told and if an automatic the TCM is turned to all things stated above.
a hard fact that. the RPM drips in OD ,overdrive and TCC lockup
the service manual lists 5 transmissions
A340F, A340H, A440, A442F and A343F units
top 2 are A340e & A340f (USA answers me) 2wd/4wd

A340F (30-40LE) 4speeds + tcc

seen too on
2000-2004 Tundra (4x2)
A = Aisin-Warner Automatic.
340 generation 3. 3L v6 used.
E=electronic shifted (TCM brain
F= 4wd same as E shifted.
3 electrically controlled solenoids for shifting and torque converter(TC) lock up(TCU runs the SHOW)

There is s TV cable here too, that causes upshifts late or early.
super hard top find this, Asian boxes. but here goes.
?1st: 2.80
?2nd: 1.53
?3rd: 1.00 (end to end lockup , look ma' NO gears here !)
?4th: 0.75 (23-spline, 0.705 21-spline
4th gear cam be less on smallest engine.(less rpm drop)
now you learn vast version of transmissions exits.
I read the side of box and it tells me the model there fully, every time.


so are you not getting 4th gear OD or the TC lockup failing
scan the PCM see if there are P07xx errors"? tranny errors. ?

in 3rd gear the RPM is the axle ratio and tire diameter (pi X r squared is circum and distance moved is that)

I can tell you the math below see the online calc. at end here.
and some TC slip. (it slips not locked up)
4 gear is RPM ,= is 0.75 x 3rd gear RPM. and tc slip.
TCC lock up is is less RPM but that depend slip and hills.
that is why I call them slush pumps, TC SLIPS and turns HP in to wasted heat and is why TCC was mandated by the EPA, for more MPG, and less waste.
that is how the pump slips as they say.

why not just see if all gears work (count them with easy right foot on flat earth)
and TCC locks up, in 4th
and scan the PCm for errors.
1,2,3,4+TCC is really like 5th speed, if you noodle that.
4-1/2" gear,(5th) locked.
make sure TV cable not rusted and jammed up and for SURE not jammed in the Pulled out position, rusted, there. and is WOT
wot is wide open throttle and that make the tranny shift way late
or never goes past 3 gear... test it.(or worse 2nd)
I see folks put a new transmission $2500 for the want of $20 cable.
wow. that. The TV cable bad is an on car fix.
P0750 to P0770 are all tcc errors to the box. scan it if gears ever shift wrong. and speed sensors failing or clutch packs slipping in the box,will dtc code out too.

so in 3rd gear the axle 3.4L auto T100 4x4 should have 4.30 gears.
so 1:1 x 4.3 is still 4.3 so 3000 rpm the read prop shaft.spins

at 3000 rpm and axles spin 698 RPM( AND TAD LESS TC SLIPS.)
knowing tire circumstance or diameter. nets speed.
manual trans runs 4.10 axles. (and no slip at all)
if not running stock tires the SPEEDO lies to you.
taller large tires spin slower and VSS lies. to cluster.
called ticket getter
235/75R15 (stock'ish)
Diameter : 28.9"

here is 4.3 axles.
3rd gear, 60mph , axle above 28.9" stock tires
is 3000 RPM
so shift to 4th, be on flat ground and light right foot and not hills]
and TV cable not JAMMED (rusted and locked out)
https://purperformance.com/p-29669-rpm-calculator.html

so 4th OD is, what .75 x 3000 is 2250 RPM (my guess never seen)
TCC locked up ,is less RPM, a bit.

so learn to scan any TCM(PCM) when gears fails.
scan it. now.

check around gear box repair shops to see if there is a replacement box that has an overdrive gear (5th)
if it is an automatic , the problem may be that overdrive is not coming in and that will drop the rpm 250 rpm and increase the speed up to the 75 mph mark
there is nothing wrong in the box as the rpm and the speed are about right in relation to the diff ratio(not mentioned )
3200 rpm with a overdrive manual runs around 74 mph or 120 km/hr
another method is to put a diff in with a taller ratio
example --current 4.1 back to 3.2

It is impossible to calculate with out knowing the over drive ratio (5th gear) and the diff ratio and tire size but with most vehicle with 5 speed boxes it should be in the 3000 to 3500 rpms range
The average vehicle at 74 miles/hr or 120 k/h runs around 3200 rpms
it doesn't matter how many cylinders or if 4x4 or make of vehicle , the rpms is tied to the ratio of the gear and the diff and the circumference of the tires
Sorry , it cannot be more exact than that

there are R, 1,2 and D gears, all 3 dead?
the automatic transmission is failing?
so tell the full story.
1: i get in car start engine and select, drive,
2: i step on the throttle pedal, the RPM goes to 1000 and stops
engine bad,(100 related reasons) weak engine.
2b: I do same the RPM goes to way over 3000 rpm engine screams
in bar stool words
this is called transmission, bad. (for 100 reasons)

1: make sure shift cable works like new, read the FSM on the checks.
2: make sure levels are correct per the operators guide, do not guess.
read the guide and do it right. not like engine checks. of oil at all.
if fluid pink or red, or brown and black or black and full of metal flakes.???? ever do a tranny serviced (full) this DECADE? hummmmm........
3: fuses good. all fuses.
4:if here, RIP tranny

Low fluid or too much ATF? (foaming it up and killing bearings)

p07xx is tranny DTC codes. (errors)
TCC lockup failure. (the TCM commanded the lock and
the tail shaft sensor did not rise in RPM
that is the engine RPM does not match tail RPM or 1:1 ratio.
which is LOCK ratio.

1500 is speed sensor , reads wrong,
No Vehicle Speed Signal to TCM.

1624 means.
MIL Request Signal from TCM to ECM.
the means simply the Tcm SAW and error and sent that error up stream to ECM. creating 1500.
remember the ECU never knows what part is bad.
NEVER ! it only knows, the tests failed. (monitors)
the first thing i do is find out which VSS failed.
on some cars there are 2 to 5
the first speed sensor is RPM does the scan tool show correct engine RPM? y/n
if yes,
does the scan-tool show correct MPH? sensor 2.
y/n if not fix that first.
the TCM function (tranny brain must not be lied to, in this order)
engine RPM , MPH.
and last the tranny its self as VSS (rpm) sensors. 1 to3.
my guess, (too lazy to look it up) has 1 sensor on the tranny tail.
if all is good and 1500 means VSS 2 tranny tail is fibbing.
then its one of 3 things.
(all others good)REMEMBER the TCM does comparisons to all speed sensors to shift the car correctly so the front sensor count first. then last the rear.
VSS2 lies. this is bad bad tranny (slips) bad wires to VSS2 or bad VSS2.
most TCM go to limp home when the tranny slips to stop burning up the clutch packs. may skip gears too.

now what does slips out of gear mean. a neutral FLARE?
or down shifts,
if the tranny ever slips. this is bad news.
if it does slip 1500 is only the warning that it did
it say RPMs go out of control and threw 1500 pronto.

Try to think(sic) like a TCM what would you do if the tranny malfs.
answer, throws codes.
and goes to limphome, if necessary, (FSM show these facts)
so does alldata dot com
what i do is try to get tranny to slip. using all gears.
if it slips ,its bad.
The TCM can not run a slipping tranny.
the TC does slip, but the TCM has that all figured out. (modeled)
not locked, and locked it must not.
good luck and do ask questions.

6.4L Power Stroke Diesel V-8 ... 350 hp @ 3,000 rpm. Torque. 365 lb-ft @ 3,750 rpm. 457 lb-ft @ 3,250 rpm ...

This is what your codes mean:

Trouble Code-P0734 (A/T Additional Gear Ratio Error In Fourth Gear)

Trouble Code Conditions:
Vehicle driven to a speed of 4-37 mph at more than 500 rpm, gear selector in 4th Gear in Drive, and the PCM detected too much difference in the engine speed and output shaft speed.

Possible Causes:

• Customer may complain of intermittent 4th gear operation
  
• O/D and 2/4 pressures less than 75 psi
  
• O/D or 2/4 clutch volume indexes out of specification
  
• O/D accumulator seals are damaged
  
• Transmission enters "limp in" mode running in 4th gear
  

Trouble Code-P0735 (A/T Gear Ratio Error Fourth Prime)

Trouble Code Conditions:
Vehicle driven any forward Gear, and the TCM detected the ratio of the Input speed to the Output Speed did not match the current Gear Ratio (this test can take up to 5 minutes).

Possible Causes:

• Related Gear Ratio trouble codes may be stored (note that some of these Gear Ratio trouble codes may be intermittent)
  
• Transmission has internal problems or damage present
  

You have a transmission problem.

From the service manual:

Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment
NGEC0549
PREPARATION
NGEC0549S01
1) Make sure that the following parts are in good order.
I Battery
I Ignition system
I Engine oil and coolant levels
I Fuses
I ECM harness connector
I Vacuum hoses
I Air intake system
(Oil filler cap, oil level gauge, etc.)
I Fuel pressure
I Engine compression
I EGR valve operation (If so equipped)
I Throttle valve
I Evaporative emission system
2) On air conditioner equipped models, checks should be carried out while the air conditioner is OFF.
3) On automatic transmission equipped models, when checking idle rpm, ignition timing and mixture ratio,
checks should be carried out while shift lever is in “N” position.
4) When measuring “CO” percentage, insert probe more than 40 cm (15.7 in) into tail pipe.
5) Turn off headlamps, heater blower, rear defogger.
6) Keep front wheels pointed straight ahead.
7) Make the check after the cooling fan has stopped.

SEF976U
3. Open engine hood and run engine at about 2,000 rpm for about 2 minutes under no-load.
SEF977U
4. Perform diagnostic test mode II (Self-diagnostic results). Refer to EC-644.
SEF217U
OK or NG
OK ' GO TO 2.
NG ' 1. Repair or replace components as necessary.
2. GO TO 2.
BASIC SERVICE PROCEDURE VG33E
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont’d)
EC-616
2 CHECK IGNITION TIMING
1. Run engine at about 2,000 rpm for about 2 minutes under no-load.
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-load, then run engine at idle speed.
SEF978U
3. Turn off engine and disconnect throttle position sensor harness connector.
SEF975R
4. Start and rev engine (2,000 - 3,000 rpm) two or three times under no-load, then run at idle speed.
5. Check ignition timing with a timing light.
SEF371S
15°±2° BTDC (in “P” or “N” position)
OK or NG
OK ' GO TO 4.
NG ' GO TO 3.
GI
MA
EM
LC
FE
CL
MT
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
BASIC SERVICE PROCEDURE VG33E
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont’d)
EC-617
3 ADJUST IGNITION TIMING
1. Adjust ignition timing by turning distributor after loosening securing bolts.
2. Turn off engine and connect throttle position sensor harness connector to throttle position sensor.
SEF972R
' GO TO 2.
4 CHECK BASE IDLE SPEED
With CONSULT-II
1. Read idle speed in “DATA MONITOR” mode with CONSULT-II.
PEF356V
700±50 rpm (in “P” or “N” position)
Without CONSULT-II
1. Check idle speed.
700±50 rpm (in “P” or “N” position)
OK or NG
OK ' GO TO 6.
NG ' GO TO 5.

That is normal,If you do the same speed in 4th gear the rpm's will almost double.

The rpm's will repond faster in a manual than an automatic.

In a manual the engine supplies the power required directly to the gear that you have selected thus the engine rpm's will increase or decrease as needed.

Since this is an intermittent problem, first try to determine if the problem arises due to one of these many intermittent problems:

* Vehicle vibration
* Heat sensitive
* Freezing
* Water intrusion
* Electrical load
* Cold or hot start up

If you can't isolate the cause of the intermittent problem, you can try adjusting the Idle Speed/Ignition Timing/Idle Mixture Ratio:

Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment

PREPARATION
1) Make sure that the following parts are in good order.

* Battery
* Ignition system
* Engine oil and coolant levels
* Fuses
* ECM harness connector
* Vacuum hoses
* Air intake system
* (Oil filler cap, oil level gauge, etc.)
* Fuel pressure
* Engine compression
* EGR valve operation (If so equipped)
* Throttle valve
* Evaporative emission system

2) On air conditioner equipped models, checks should be carried out while the air conditioner is OFF.
3) On automatic transmission equipped models, when checking idle rpm, ignition timing and mixture ratio,
checks should be carried out while shift lever is in “N” position.
4) When measuring “CO” percentage, insert probe more than 40 cm (15.7 in) into tail pipe.
5) Turn off headlamps, heater blower, rear defogger.
6) Keep front wheels pointed straight ahead.
7) Make the check after the cooling fan has stopped.

INSPECTION PROCEDURE

1 INSPECTION START
1. Visually check the following:
I Air cleaner clogging
I Hoses and ducts for leaks
I EGR valve operation (If so equipped)
I Electrical connectors
I Gasket
I Throttle valve and throttle position sensor operation
2. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
Ensure engine stays below 1,000 rpm.
3. Open engine hood and run engine at about 2,000 rpm for about 2 minutes under no-load.
4. Perform diagnostic test mode II (Self-diagnostic results).
OK or NG
OK ' GO TO 2.
NG ' 1. Repair or replace components as necessary.
2. GO TO 2.

2 CHECK IGNITION TIMING
1. Run engine at about 2,000 rpm for about 2 minutes under no-load.
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-load, then run engine at idle speed.
3. Turn off engine and disconnect throttle position sensor harness connector.
4. Start and rev engine (2,000 - 3,000 rpm) two or three times under no-load, then run at idle speed.
5. Check ignition timing with a timing light.
15°±2° BTDC (in “P” or “N” position)
OK or NG
OK ' GO TO 4.
NG ' GO TO 3.

3 ADJUST IGNITION TIMING
1. Adjust ignition timing by turning distributor after loosening securing bolts.
2. Turn off engine and connect throttle position sensor harness connector to throttle position sensor.
' GO TO 2.


4 CHECK BASE IDLE SPEED
1. Check idle speed.
700±50 rpm (in “P” or “N” position)
OK or NG
OK ' GO TO 6.
NG ' GO TO 5.

5 ADJUST BASE IDLE SPEED
1. Rev engine (2,000 to 3,000 rpm) 2 or 3 times under no-load then run engine at idle speed.
2. Adjust idle speed by turning idle speed adjusting screw.
700±50 rpm (in “P” or “N” position)
' GO TO 6.

6 CHECK TARGET IDLE SPEED
1. Turn off engine and connect throttle position sensor harness connector.
2. Start and rev engine (2,000 to 3,000 rpm) 2 or 3 times under no-load then run at idle speed.
3. Check idle speed.
750±50 rpm (in “P” or “N” position)
OK or NG
OK ' GO TO 9.
NG ' GO TO 7.

7 DETECT MALFUNCTIONING PART
Check the following.
1. Check IACV-AAC valve and replace if necessary.
2. Check IACV-AAC valve harness and repair if necessary.
3. Check ECM function by substituting another known good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
' GO TO 9.

9 CHECK FRONT HEATED OXYGEN SENSOR LH SIGNAL
1. Run engine at about 2,000 rpm for about 2 minutes under no-load.
2. Set “Left bank front heated oxygen sensor monitor” in the Diagnostic Test Mode II.
3. Make sure that MIL goes on more than 5 times during 10 seconds at 2,000 rpm.
OK or NG
OK ' GO TO 12.
NG (MIL does not blink.) ' GO TO 17.
NG (MIL blinks less than 5 times.)
' 1. Replace front heated oxygen sensor LH.
2. GO TO 10.


10 CHECK FRONT HEATED OXYGEN SENSOR LH SIGNAL
1. Warm engine to normal operating temperature.
2. Run engine at approx. 2000 rpm for approx. 2 minutes under no-load.
3. Set “Left bank front heated oxygen sensor monitor” in the Diagnostic Test Mode II.
4. Make sure that MIL goes on more than 5 times during 10 seconds at 2,000 rpm.
OK or NG
OK ' GO TO 13.
NG ' GO TO 11.

11 DETECT MALFUNCTIONING PART
Check the following.
1. Check fuel pressure regulator.
2. Check mass air flow sensor and its circuit.
3. Check injector and its circuit.
Clean or replace if necessary.
4. Check engine coolant temperature sensor and its circuit.
5. Check ECM function by substituting another known good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
' GO TO 2.


13 CHECK FRONT HEATED OXYGEN SENSOR RH SIGNAL
1. Set “Right bank front heated oxygen sensor monitor” in the Diagnostic Test Mode II.
2. Make sure that MIL goes on more than 5 times during 10 seconds at 2,000 rpm.
OK or NG
OK ' INSPECTION END
NG (MIL does not blink.) ' GO TO 16.
NG (MIL blinks less than 5 times.)
' 1. Replace front heated oxygen sensor RH.
2. GO TO 14.


14 CHECK FRONT HEATED OXYGEN SENSOR RH SIGNAL
1. Warm engine to normal operating temperature.
2. Run engine at approx. 2000 rpm for approx. 2 minutes under no-load.
3. Set “Right bank front heated oxygen sensor monitor” in the Diagnostic Test Mode II.
4. Make sure that MIL goes on more than 5 times during 10 seconds at 2,000 rpm.
OK or NG
OK ' INSPECTION END
NG ' GO TO 15.

15 DETECT MALFUNCTIONING PART
Check the following.
1. Check fuel pressure regulator.
2. Check mass air flow sensor and its circuit.
3. Check injector and its circuit. Clean or replace if necessary.
4. Check engine coolant temperature sensor and its circuit.
5. Check ECM function by substituting another known good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
' GO TO 2.
16 CHECK FRONT HEATED OXYGEN SENSOR RH HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect front heated oxygen sensor RH harness connector.
4. Check harness continuity between ECM terminal 50 and front heated oxygen sensor RH harness connector.
Continuity should exist.
OK or NG
OK ' 1. Connect ECM harness connector.
2. GO TO 18.
NG ' 1. Repair or replace harness.
2. GO TO 9.

17 CHECK FRONT HEATED OXYGEN SENSOR LH HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect front heated oxygen sensor LH harness connector.
4. Check harness continuity between ECM terminal 51 and front heated oxygen sensor LH harness connector.
Continuity should exist.
OK or NG
OK ' 1. Connect ECM harness connector.
2. GO TO 18.
NG ' 1. Repair or replace harness.
2. GO TO 9.

18 PREPARATION FOR “CO” % CHECK
1. Disconnect engine coolant temperature sensor harness connector.
2. Connect a resistor (4.4 kW) between terminals of engine coolant temperature sensor harness connector.
' GO TO 19.

19 CHECK “CO” %
1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-load, then run engine at idle speed.
3. Check “CO” %.
Idle CO: 1.5 - 9%
After checking CO%,
a. Disconnect the resistor from terminals of engine coolant temperature sensor.
b. Connect engine coolant temperature sensor harness connector to engine coolant temperature sensor.
OK or NG
OK ' 1. Replace front heated oxygen sensor LH.
2. GO TO 10.
NG ' GO TO 20.

20 DETECT MALFUNCTIONING PART
Check the following.
1. Connect front heated oxygen sensor harness connectors to front heated oxygen sensors.
2. Check fuel pressure regulator.
3. Check mass air flow sensor and its circuit.
4. Check injector and its circuit.
Clean or replace if necessary.
5. Check engine coolant temperature sensor and its circuit.
6. Check ECM function by substituting another known good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
' GO TO 2.