97formulanc

I have a 97 firebird formula and just today on the way to work it would not shift into 3rd or overdrive. It has done this once before but went away when i came to a stop light. But right now it hasnt been able to shift into 3rd or overdrive at all.. Maybe the solenoids? or just rebuild the transmission? any suggestions??

mrvedit

Replacing the two shift solenoids certainly would be worth a try. Another possible problem is the "3rd accumulator check ball" in the servo area. If it leaks, you won't have 3rd, but they can get sticky so that they sometimes seal and sometimes not. It is in the servo area:



If a trans shop determines it is bad, it can be replaced without removing the trans.

97formulanc

thanks i had a feeling it was the solenoids but i just wanted others opinions. Im going to have it looked at tomorrow

97formulanc

well i replaced the solenoids this weekend and while replacing the 2-3 solenoid i realized that the spring that the piston that pushed out the solenoid was stuck in and wont come out.. could this be a reason? and if so how can i fix it?

mrvedit

Are you saying the Valve (not piston) behind the 2-3 solenoid is stuck or the spring behind the valve is stuck? I have not seen either stuck in even very old and worn valve bodies. If just the spring, try long need nose pliers.

(I have holiday obligations today, but have two valve bodies on my work bench and will be glad to help later.)

mrvedit

Update/correction to my previous post this morning...

Just to be oriented correctly, note the cover plate with the three bolts on the side of the valve body. The solenoid nearest it is the 1-2 shift solenoid, which has a valve and spring behind it; you notice the spring when you remove/install the 1-2 shift solenoid.
The next solenoid is the 2-3 shift solenoid; it has two valves behind it and NO springs.

Therefore when you replace the 2-3 shift solenoid, you will not feel any spring action.

97formulanc, assuming you ID'ed the solenoids correctly, there is no spring for the 2-3 solenoid and you are good to go.

mrvedit

Just to add a picture taken from underneath the car with the pan and oil filter removed:



The 1-2 shift solenoid is in the upper right hand corner. This is the "spring loaded" one.
The 2-3 shift solenoid is the lower one; this one has no spring.

97formulanc

well if thats not it do you have any other suggestions of what could be wrong with the transmission? maybe the clutch plates for 3rd gear?

mrvedit

Completely worn 3/4 clutch plates is not only possible, but likely. I first try to suggest other possibilities which don't require removing the trans. Things like replacing the shift solenoids are part of a quality rebuild, so that is always worth a try. (If you get it rebuilt, tell them you replaced them already and get a credit.)

Other possibilities include the leaking "3rd accumulator check ball" already mentioned, or low line pressure due to a worn out pump or a very worn valve body.

Of course, you have a 15 year old trans and probably 150K+ miles on it and it is time for a rebuild anyway. I do think that is your best/only bet right now.

97formulanc

thats what I'll probably do. I forgot to mention that when i bought the car the transmission was just rebuilt and i have only put 5,000 miles on the car. I still have the receipt from the guy i bought it from and I'm going to call the shop today. but if they decide that they dont want to work anything out then I'll just rebuild it myself.

00shortbox

3-4 clutches are very common to burn out in the 4L60 transmissions, don't know how many I've done! 90% of the time it's just due to the weak design, with no piston seal leaks or anything. Another thing I've seen is worn out bushings in the oil pump which will tear the teflon seals on the turbine shaft.

Monzsta

Don't forget that check ball that loves to impale the separator plate. I think it's 2nd. When it sticks, it causes a "fight" between 2nd and 3rd, with the 3/4 clutches losing every time.

Check this thread out.

http://m.modmotortech.com/forums/sho....php?t=1221002

mrvedit

Sorry to hear the trans is slipping at only 5000 miles after a rebuild. Sounds like a stock rebuild with a few shortcuts taken.

Good point from Monzsta on the check ball. A quality rebuild should always include a new separator plate. (A "shortcut" rebuild might reuse the old one.) Transgo makes a universal one that fits '96 through '06.
Sonnax makes plastic check ***** that wears the plate less and (supposedly) seal better:

http://www.sonnax.com/system/announcement/10000-08.pdf

In any case it seems likely you need new 3/4 clutches. As 00shortbox points out, it might not need anything else, although I would check everything related to proper 3rd gear apply. Just get a quality 7 or 8 friction set this time.

97formulanc

im taking it out tomorrow and getting the whole transmission rebuilt because i just found out that the trans wasnt rebuilt at all. it was just salvaged. the previous owner didnt tell me that. i had to call the shop it was originally worked on to find that out.
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