Rick Speed

iTrader: (55)

1998 Trans Am
Ok first the back story. Friday my trans line clamp broke and the hose popped halfway off tossing all my fluid on the freeway. I didn't try to keep it going letting slip or anything. I fixed the line and filled it up. The trans was fine all weekend. then Monday after work 4th would not engage or even try. the trans shifts to 2nd and 3rd perfect then it's like it just stops there and doesn't even try to go to forth. No slipping at all that I can tell.. its as if it is a 3speed trans.

If it was bad clutches wouldn't it at least try to go to forth or no?

bbond105

Recheck the fluid level.

Rick Speed

iTrader: (55)

Friday I put 4 qts in and Monday I put 2 more in still the same

mrvedit

Why would you put 2 more quarts in on Monday after presumably filling it on Friday?
Is it still leaking or are you unsure if it is full now?
(I'm not trying to be obnoxious, just trying to help you solve this mystery.)

I cannot immediately think of how any damage due to fluid loss would only affect 4th gear. I would start by putting a scanner on the car which can indicate which gear the PCM is commanding. Any trans shop can do this.
If the PCM is not commanding 4th gear, I would suspect the shifter alignment or the pressure manifold switch.
If the PCM is commanding 4th gear, I would suspect the servo, the band or a stuck valve in the valve body.

Rick Speed

iTrader: (55)

ok well I didn't check the fluid level Friday.. it was 7 degrees outside and I was freezing while laying in the snow to fix.. So I added the 4qts and it was working and I did not recheck it to verify level.. so when Monday rolled around and I had this issue start I checked the fluid level figuring I didn't get enough in and it was low so I added 2 qts to get it to the full mark. still didn't shift so the way it is acting I'm not sure,, I really hate autos lol

My initial fear was the clutch was burnt and the material was actually in the fluid that got spit out and it took till Monday for it to finally let go.

mrvedit

Understand the cold "thing" as we are in the same boat.
I assume you know that the level is checked with the engine running, although 1" above the full mark with the engine off is a good starting point.

I think you best bet is to drive the car to a local independent trans shop. Their scanner will indicate what the PCM is commanding and it can also command any gear.

Good luck.

Rick Speed

iTrader: (55)

Ok I had a chance to drive it with my scanner on it today. The scanner says it's shifting into 4th even gives me and error time and shift time similar to 3rd shift but it's definitely not shifting

mrvedit

Ok, I would next suggest measuring how much end play your servo has, which is an indicator of how worn your band is. Bummer if the loss of fluid wore the band, but its an easy check:
Put a short ruler next to the servo cover, and using a crowbar, press on the cover while estimating how much it moves inward. The optimal value is 1/16" to 1/8"; around 3/16" the band may start to slip and by 1/4" you have probably lost 2nd and/or 4th.

Usually a worn band manifests itself as slippage in 2nd gear before problems with 4th, but not always.

If the clearance is OK, my next idea will be to remove and clean the valve body, but lets wait until we know the end play.

mrvedit

Wanted to add that a defective shift solenoid A (also called 1-2 shift solenoid) would prevent a shift from 3rd into 4th. However, it would most likely also prevent a shift into 2nd. The shift solenoid have tiny filters in them which can get clogged.
Are you sure the trans is shifting into 2nd and not just delaying and then shifting from 1st into 3rd?

Also, what scanner did you use? Some people here have trouble finding a scanner that shows the commanded gear.

Rick Speed

iTrader: (55)

I'm using a Matco determintor. It can feel all the shifts esp, second because it's got a tune that hits second pretty hard

performabuilt

iTrader: (25)

I would guess either the band clearance has opened up and the 4th servo piston just no longer has enough travel or though unlikely the 3-4 shift valve could be stuck in the VB but that would not likely be caused by the leak. If second firm I would lean toward the band clearance just being to high. possibly the band burned a bit during the fluid incident.

Rick Speed

iTrader: (55)

I'm getting 3/16"

Rick Speed

iTrader: (55)

Also took servo out and idk if it's normal or not but the fourth servo falls out of the cap with no pressure like the seal is worn ?

mrvedit

3/16" is a lot, but usually still workable.
The 4th servo comes out pretty easily. There is a black "cut" seal ring on it which comes off very easily. You could try putting on another one; a servo seal kit is less than $10.
IIRC Sonnax makes an o-ring kit that seals much better than the "cut" stock seal rings.

Alternatively, you may get a bit more life out of the trans by lengthening the servo pin. I described this in several threads and got "testimonials" that it worked:

Lengthened Servo Pin:
https://ls1tech.com/forums/automatic...t-trouble.html
https://ls1tech.com/forums/automatic...-gear-all.html
https://ls1tech.com/forums/automatic...ckup-help.html
It Worked:
https://ls1tech.com/forums/automatic...cond-only.html
https://ls1tech.com/forums/automatic...e-2-fixed.html

You can either weld on a "glob" and grind it down or buy a longer pin and grind it down as needed. With 3/16" end play I am pretty confident this will work and maybe give you another 10,000 miles before the band is completely smoked.

Rick Speed

iTrader: (55)

Sounds simple enough except I don't think there is enough space to get it out lol

mrvedit

Ahh, I thought you already had it out.
I don't know the exact steps on a Gen4, but you likely have to remove the torque arm and driveshaft and, while supporting the trans, remove the rear mounting and drop it far enough to get the servo out.

Some of the OPs in those threads had SUV/Trucks and the servo then comes out easily.

Perhaps some Gen4 owners here have tricks or time estimates for removing the servo.

Rick Speed

iTrader: (55)

Well I figu I'd let you know you CAN take it out piece by piece while in car. I welded and ground it back down and it works like a charm!!! Thanks

mrvedit

Excellent! Glad to hear that lengthening the servo pin worked for you too. Keep in mind this is a "temporary" fix and that your band will likely wear down to nothing in 10,000 miles or so.

bbond105

Thanks so much for posting an outcome. Some many just leave us wondering what the outcome was.