Azrael91966669

i just installed an 85 700r4 as i needed a replacement "cracked bellhouseing" and this one was free. the trans seems fine for every other gear but it anything above 20 mph will not downshift back to 1st it only drops to 2nd at a very low Rpm . at 20 mph when it does downshift it drops it to 2500 or so into 1st 1st gets nearly to 45 mph before it shifts to 2nd around 5600 rpm . i would really like the car to shift like it did with 91 trans would down shift at 36mph instead of 20. currently 25 rolls kinda suck as i feel it should have downshifted. i guess even the 2nd gear downshifts are off only downshifts below 60 when it used to downshift at 65 to pass would hold 2nd till 79 80 now it only downshifts at a max of 60 i dont want to change the wot upshifts . they are correct . i want to change the wot downshift points . can this be done? is this a 85 trans issue? or something else i can look into? engine is 91 lb9 TV cable is set correctly but its a 91 TV cable fuild level is correct im useing the Tq converter from my 91 4L60 car has 3.23 gears with the correct speedo gear

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Red 1991 RS ,C&C t-tops,full leather interior,145 speedo ,brakes 4 wheel PBR disc 12' up front 11.9 rear,engine 90 lb9 sd tpi 1.6 full roller rockers crank underdrive pulley,trans 4l60 with b&m shift kit,alloy driveshaft,rear ten bolt auburn posi 3.23 gears,Edelbrock TES with Flowmaster 80 series muffler,1le springs ,soild 36mm front and 24 mm rear swaybars

performabuilt

Swap the govenor from the 93 unit to the present unit and that may get you there.

Azrael91966669

its a current unit is 85 old unit is 91 4l60 so says the "service manual" not a 93

thought the govenor only dictates the upshift points ?

im needing the trans to Kick down into lower gears a little higher then its currently doing
will the govenor do that?

i dont what the trans to shift any higher already shifting at 5600 in 1st
top of 2nd is 5400 wont changing the goveror make it shift higher or lower

im just confused by what causes downshifts
the trans came from an 85 tpi z28 with 3.23 gears i had figured the shift points would be the same or better since my old trans was for 91 Rs 2.73 gears

Azrael91966669

ok i swapped out he govenor and now its shifting at 4200 rpm wide open throttle and 2nd is shifting at 4000 to 3rd

the govenors weights are completly differant and the units have differant stamps on them J and C c is the 91 unit has 4 weights outer 2 are thin inner a little thicker but the same springs
J 85 unit has only 2 weights both are triangle shaped

down shifts are still at below 20 mph so it didnt fix the problem only made it worse buy removing 1500 of rpm range :/
governer only seems to deal with max rpm shift points all the low mid throttle shifts are the same

Fast355

The governor plays a BIG role in part-throttle shift points, but most stock governors are calibrated to upshift about the same rpm on a stock vehicle.

Azrael91966669

the last engine i had did shift at 5100 and 1-2 with its 91 trans
this 85 trans is shifting at 5600 1-2

when i use the govenor from the 91 trans in the 85 trans .
only the full throttle shift have 1-2 and 2-3 have changed both are about 1000 rpm lower then they should be

but the part throttle shifts are the same no differance

that tells me the govenor only deals with setting the max engine rpm shift "redline" shifting

apperently ill be putting the 85 govenor back into the 85 trans as apperently

there is something else differant with these transmissions

Fast355

The governor EFFECT part-throttle shifting, PERIOD!!!!!! I don't care what you think from swapping one stock governor for another. It honestly does not surprise me that one is not different than the other, the stock setups all shift south of 2,000 rpm at the lightest throttle acceleration.

Valvebody calibrations can also vary between transmissions. The higher the line pressure, typically the higher/later your shift will get. My stock governor increased nearly 1,000 rpm at WOT upshifts with a Transgo 2/3 Shift Kit. The part-throttle shifts also came up. You can alter the weights and springs on the governor to get the shift-points where you like them. Make sure the TV Cable is also correctly adjusted. I was able to EASILY change part-throttle and WOT shift point changes through small changes in the governors weights and springs.

Azrael91966669

fast the thing is even with completely differant weights on these govenors

it still is only doing a full throttle downshift below 20 mph

i am not talking about "upshifts" full throttle upshifts where changed lowered by 1500 rpm
but all other non full throttle "upshifts where at the same rpms"

also my "down shift points have also stayed the same" so im saying

the govenor is not the issue the 91 has 2 sqaure weights on each side
85 gov has 1 weight each side and there also thiner and shaped like a triangle

the springs are differant colored aswell

so why is everything about the govenor differant but yet only the redline wot upshift differant

and as i explained before my old trans had higher "down shift speeds"

ie i could be doing 30 mph floor it and it would downshift into 1st

now with the 85 trans i floor it from 30 and only get a downshift to 2nd at around 2000 rpm that isnt so bad

what is bad is flooring it from 21 22 mph instead of downshifting into 1st like i want it to it hits 2nd 1500 and has to go threw the entire gear
slower then had it shifted into 1st correctly


i was told to swap the govenor it made it worse as no changes other then lower the wot shift points

godreject

don't mean to highjack but quick ?
what are the upshifts supposed to be at, i just recent;y replace my tranny in my 91 1-2 shift is at around 3500 way early right, downshift to 1st gear is at about 10mph could my tranny be ill adjusted off, seems like im having similar issues

Azrael91966669

35 was the highest it would downshift to 1st now with a replacement trans its 20 the highest it would down shift full throttle upshifts on mine are 5600 rpm in 1st and 5400 upshift to 3rd

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Red 1991 RS ,C&C t-tops,full leather interior,145 speedo ,brakes 4 wheel PBR disc 12' up front 11.9 rear,engine 90 lb9 sd tpi 1.6 full roller rockers crank underdrive pulley,trans 4l60 with b&m shift kit,alloy driveshaft,rear ten bolt auburn posi 3.23 gears,Edelbrock TES with Flowmaster 80 series muffler,1le springs ,soild 36mm front and 24 mm rear swaybars

Fast355

I mentioned the valve body has some potential differences, however the governor still plays a BIG part in shift-points at both part-throttle and WOT. If the springs and weights are BOTH different it is 100% possible that one governor has the same lower rpm pressure curve as the other governor. I was able to make my WOT upshifts in my van at 6,000 rpm, however even my lightest throttle shifts were around 2,200 rpm. My WOT downshifts increased as well. It sounds like something is wrong with your TV cable or TV Sleeve and Plunger. It could possibly have S.S.S., Short Spring Syndrome. A stock 700r4 should downshift to 1st as long as the rpms are under 2,000 rpm or so in 2nd gear.

I know all too well about that low-rpm 2nd gear pull with a non-downshifting 700r4 as I did it too many times to count in a 3.08 geared fullsize van. Mine was a TV cable issue that I was able to resolve with a genuine GM cable.

Azrael91966669

my cable is a gm cable that i put on when i did the Tpi swap i ordered the cable from my work when i was working at a chevy dealer

i really was hoping it was a simple fix

freind that works for trans shop told me its because the 85 and older 700s dont have a good downshift plunger something was fixxed in later in 86


he told me as long as the trans is holding up for now wait till we get my other trans bellhouseing welded jack stands dont make good trans holders when doing engine swaps lol


he took a look at the govenors as well said the one from the 85 is correct for 5500 shift point my old 91 apperently was ment for 5000
he rebuilds these all the time

apperently the downshift issue is something that cant be corrected on this trans :/

Fast355

It CAN be...My 1983 700r4 had near INSTANT downshifts and reved to 5,500 rpm before upshifting. Its all in the spring package inside the shift valves, the TV Sleeve and Plunger and the Governor. They all have to balance out to give the correct shift timing.

TV Sleeve and Plunger is easy to swap out.

Azrael91966669

here is what i found out when i took a freinds 85 iroc out for a drive
both his car and my car have the same gears 3.23 and trans 7004r

they both suffer the same shifting issues

he bought the car new and says its done this since new

he just figured the 305 didnt have power lol



i was hoping a simple govenor swap would have corrected the problem

i do not want to mess with the upshift points at all there perfect

i only wanted the downshifts changed
i was able to change them on my lt1 wagon but its electronic

here is really all i want

when driving 35 mph if i floor it i want it to down shift into 1st
it still has 1000 rpm of range left 35mph = 4400rpm

the top if 1st is 42mph

i also want it to beable to drop into 2nd from 70 for a passing gear since 2nd hauls all the way to 80 .

currently i have to be going a max of 60 if i want it to drop down to 2nd

but i do not want to change the upshift points at all its already at 5500 for the 1-2 shift and 5400 for the 2-3 shift

if you can tell me what needs changed for this cool

if its something in the govenor is it the springs or weights

the "automatic" upshifts are they seem fine already "ie normal driving"

is there anyway to change only the downshift points and not change anything else

swapping my govenor over didnt seem to change anything but the wot upshift points

ive seen much older post on this topic but it never gets answered

"edit "

i did look up modifying the govenor for shift points but it seems the "kits" are only ment for changing the wot upshift point there not ment for changing downshifts or mid throttle shifts :/
there sold manly for people who install a new engine that say has a 6500 redline when the trans is set for 5000 there loseing to much rpm
the spring and weight kit seems to adjust that

i really wish gm wouldnt have made the tv cable also adjust the pressure would be nice to fine tune downshifts with it