5th gear 79 gs750L at 5k at 70mph it has no accel power drop to 4th put hammer down runs and accels perfect just put 140 jets in from stock 102 whats going on with it?

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.

The 5th gear noise with the 6 speed is legendary!

1st and 5th are straight cut gears. 2nd,3rd,4th, and 6th are helical cut gears. Straight cut are stronger so Harley put them in the most popular gears.

Some people swear that either Mobil Syn 75/90 or Redline Shockproof 85/140 helps.

Baker transmissions make a F6F kit that has a helical cut gear, and a thicker trapdoor to handle the increased side loading because of it, but it ain't cheap!

good maintnance what you did. but these bikes lacked power in high gear and I used to always have to gear down and pick up more spead. remember that they are a touring bike so you shouldn't even be in 5th at 50mph. try this build enough speed and stay in 4th and don't go up to 5th unless you hit at least 60mph or a bit more. I have an 04 now and guess what, they are all the same you gotta build enough speed before 5th, I toped the 110mph on mine just last week. moral of story, don't treat them like normal cruisers, stay in 3d gear when around town. 4th is just as you get on the freeway and 5th is only for freeway.
I hope this helps.

time to put a new tranny in that jet most of the time it costs to much to repair it then replace it i have done may tranny rebuilds and replacements to me i would just tell you to replace it at least you will get a better warrentee and stuff

Accelerating and going nowhere? Might need a new cat (catalytic converter).

replace fuel filter.have idle speed control checked and scan it to check the egr valve.make sure it not stuck open.

try cleaning the map sensor with map sensor cleaner.

The code you are reading is a bit misleading. The gear ratio is not incorrect, the slipping in 4th gear is what the computer is seeing and reading it that way.
Unless you can find a competent shop to do your rebuild, your only other option is to have the shop you are using stop rebuilding the one you have and get you another complete unit. There could be a problem with your original, such as slight porosity in the case, permitting a pressure drop which they are not seeing. (or they are repeating the same mistake each time they rebuild it!

You can have car put on scope and it wll show any irregularities in the ignition system. It can also be dowithout any equipment. First, loosing ALL 8 spark plug wires, Now place the spark plug wires loosly back on, just secure enough to secure. You might need 2 people. Being the miss is more consistant in gear, APPLY THE EMERGENCY BRAKE , put trans into drive and raise rpm's till miss is obvious. Remove ONE plug wire at a time, TILL THERE IS NO DIFFERENCE IN MISS. Thats the cylinder missing. Start with the spark plug, inspect, work back to wires and cap. An EXTREME result will be NO COMPRESSION.

This is a Direct result of a Bad Alternator. You can Run on what is left in the Battery for a Little while and if it sits for a While the Battery will retain enough Power to Start. You may need a New Battery in Addition.