wont shift to 4th at 90mph

D

doomdead

New member
just did the vaccum kit install from ian, tightened up the wastegate rod 3 turns from stock (i think) and did a run with the boost controller off... did very well, very smooth boost at about 10psi... i upped it to 15 (i know the chip only goes to 14.7) and the boost held about 14psi... very smooth and very strong. however i noticed at 4500 rpm, 3rd gear at 88mph it would not shift into 4th... it just kind of staggered there. i tried again, it shifted, then again and it would not. it was fine a week ago and im not low on fluids..... any ideas???

i have dm files but they're on the laptop and i lost the dongle, prob be able to get it done at work (floppy is there).....

thanks guys..
 
J

JIMATTESON

New member
Ok while somebody is on this topic my TY wont stay in park?
Is this the TV cable as well? Or is the shifter have an adjustment?
 
dgoodhue

dgoodhue

BuSTeD 4.3
JIMATTESON said:
Ok while somebody is on this topic my TY wont stay in park?
Is this the TV cable as well? Or is the shifter have an adjustment?
Click to expand...

TV cable has nothing to do with Park, I would assume this is the shifter adjustment or shift cable.
 
S

stariy

New member
Re: wont shift to 4th at 90mph

doomdead said:
just did the vaccum kit install from ian, tightened up the wastegate rod 3 turns from stock (i think) and did a run with the boost controller off... did very well, very smooth boost at about 10psi... i upped it to 15 (i know the chip only goes to 14.7) and the boost held about 14psi... very smooth and very strong. however i noticed at 4500 rpm, 3rd gear at 88mph it would not shift into 4th... it just kind of staggered there. i tried again, it shifted, then again and it would not. it was fine a week ago and im not low on fluids..... any ideas???

i have dm files but they're on the laptop and i lost the dongle, prob be able to get it done at work (floppy is there).....

thanks guys..
Click to expand...
Sorry not on subject, but what is "Ian vacuum kit"? What good about it? Do I need it? How can I get it?
Thanks :roll:
 
B

Blake

Guest
What do you mean specifically when you say it won't stay in park?
A question like this can only be answer when info is given about what started it, and when it started doing. Just saying, "my truck is doing this" won't usually render any genuine responses but I'll try.

If you have the front prop out, the truck will roll even if in park and everything is working as it should. Just put the prop back in.

There is no real adjustment on the interior shifter end. The only adjustment there is for the park neutral safety switch. This won't affect a mechanical problem.
The other end is where people generally run into problems after having the truck worked on. The little bracket that has two of the pan bolts running through it usually gets bent and needs to be tweaked to get it right again.

Another thing that can happen is the cable itself physically gets stretched or when the tranny was dropped down for service and the cable gets stretched because the shop was too damn lazy to pull the pin out of the cable and disconnect it. If this happens, it must be replaced with the correct one. This has happened to me when Guyler Buick GMC worked on my truck.

If your tranny was worked on and they removed anythig around the valve body, the nut on the inside next to where the manual shaft goes through could have been left loose but you would have trouble getting other gears as well.

There is a parking pawl inside the transmission that has a "finger" that physically engages the "teeth" on the outside of the reaction ring gear deep in the transmission. The reaction ring gear is hardened and the finger is hardened. It is possible this may have broken but I suspect you would have other serious problems in addition to this(GM's new trailblazers had a recall because this was breaking on some of the new units).

Hope this helped.
Blake
 
M

MR_MNZTR_SY

New member
ive had the propshaft out and i keep it blocked, but there have been times where it has roold for a little bit, will this cause any damage?
 
B

Blake

Guest
This is completely normal for it to roll when the prop is out. My wife did this at her university after I told her to put on the parking brake(of course she didn't do it); it rolled almost 20 feet in about 2 hours. We are damn lucky she didn't hit anything. Make sure to use the parking brake if the prop is out and also use some wheel blocks if you are on a steeper hill.

The only damage it will do from it rolling is to the truck when it hits something. :eek:
Blake
 
B

Blake

Guest
I've never done it personally but the general consensus is that it isn't supposed to shift into 4th until almost 100 mph. Something that I've heard can happen is if you are in 4th and you decide to punch it, it will go to 3rd like it is supposed to but then sometimes the TV valve the one farthest back in the valve body(the one beyond the roll pin)can get hydraulically locked and not shift up to 4th.
The people at transonline recommend a mod to the separater plate in some 700r4s that could take care of the problem. Here's a pic


vb_tvfeed.jpg


If it is "breaking up" or "hanging" then it is an ignition issue and with the timing getting retarded(if this is the case)it isn't going to upshift because the rpms aren't high enough to get the pump in the tranny to make enough pressure for the governor to let it shift up.
If your tranny has shifted to 4th in the past at wot then that would rule out the wrong tranny being in the truck.
HTH,
Blake
 
A

ABLITZ

Damn Yankee
same thing happened here

same thing happened here

when i was runnin an IS300 on the highway it wouldnt shift into 4th.i was doin 90-100,i had to let off a little for it to shift. :-?
 
D

doomdead

New member
im still stumped... last week everything i thought was fine. and like i said before when i launch and hold at about 85-90 it usually shifts into 4th, never ever at 100. well after doing the vaccum kit and adjusting the wastegate it will shift once but not again... the rpms climbed to 4575 and kind of just sat there... at one point i felt the truck lurch alittle as it hit the rev limiter... i dont know, the tv cable seems to be fine. but not shifting into 4th from a stop is a bit confusing... im not low on tranny fuild. its still good.... i did a checkup on the tranny not to long ago everythign has been normal..... could it be vaccum related or (prob an obvious no) but wg related?
 
J

JIMATTESON

New member
THANKS BLAKE !!
My wife admitted she ran over a plastic chair (OUCH)
The cable must have gotten streched, thats what my
mechanic told me and had fixed. All is well again
 
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