evil t/a

I dont have 4th. 89 700r4. I took a look at the governor and it look fine I changed valve bodies and nothing changed, I made sure the transmission was actually in fourth and that the megashifter wasnt binding or anything. I changed TV cables. I even pulled the servo out and cleaned and replaced all of the seals(except the vette orings but they dont effect 4th). Still nothing. The car goes through all of the other gears perfectly and it runs like a bat out of hell. What the hell could this be? 4th worked fine before I had the transmisson rebuilt and upgraded but I hasnt worked at all since I put it back in. I am thinking that maybe the 4th apply piston has too much travel and isnt making the pin contact the band. I found this picture that has a shim for that but it is the only one that I have seen. Any suggestions? I have had the servo out twice and ****ing with that housing clip and paying for those housing orings is not fun. Heres the picture notice the shim between the housing and the 4th piston

Floor guy

I have no idea why the illustration shows discarding the snap ring. The snap ring is nescessary. If you did toss it, I would recommend finding it and reinstalling.

evil t/a

the ring is still there.

postal

The prob is probably somewhere elso if the servo was that much off you would have a prob in other gears esp 2-3 shift.are you not getting into 4th at all or not getting lockup?Check your piston travel with the back tires off the ground see if the band is engaging , draging ect.

chevy2ss

why dont you do a search. this is almost as common a question as do 4th gen seats bolt in a 3rd gen

evil t/a

LOL you *******

Floor guy

I do not know the answer but figured Iwould check the atsg book. They list:
governor
pump cover retainer or ball assembly missing or damaged.
Many valve body possibilities.
Servo, they did comment on possible porosity problems
3rd accumulator ck ball leaking3-4 accumulator seal leaking
missassembled band - I assume they mean not tanged properly.

fly89gta

iTrader: (1)

Do they bolt right in??

Precision Trans

Evil:

Since changing valve bodies had no effect, we can assume for the moment that you do not have a VB problem. (i know, I know; never assume anything. But since I can't lay my hands or even eyes on your unit, I have to assume.)

Drop the pan and the VB along with the auxilliary VB and the separator plate. Remove the 3-4 accumulator piston and spring. You should see a feed hole about 3/16" in dia, and a small cup plug (bleed orifice cup) about 1/4 of the way around the bore from the feed hole. If this cup is missing you will have no 3-4 shift. Check the hole in the piston for excessive clearance with the pin, also, along with the piston seal.

If you have any further questions, please do not hesitate to contact us.

Don

Kingtal0n

If it goes into 2nd, but not fourth, its either valve-body related ( such as 4th gear accumulator )...

in my case, it was the 4th gear servo piston seal. the seal had ripped (i guess from incorrect installation during rebuild) so the fluid that should have pushed the 4th gear piston into the band could lock around the reverse input drum, which is how fourth actuates. Pull the cover out off the servos, and inspect the seal on the first piston you see (4th gear piston).