Thread: Strange Transmission Problem

Just installed a "mystery" transmission that I rebuilt, and getting fluid draining back into pan causing all sorts of issues.

As a preface, the "mystery" transmission I am referring to came out of a donor 2000 grand prix gt with 160,000 miles on it at a junk yard. I have no knowledge about how this transmission ran whatsoever before the rebuild.

As for the rebuild, fortunately I am not referring to the hack jobs of just replacing a few clutches and solenoids and calling it a day, I completely stripped this transmission down to the case and rebuilt with raybestos clutches and borg warner solenoids. I replaced all seals, o-rings, steels, frictions, electronics, bushings, filter, bearings, switches, and new Dex6 after completely cleaning and inspecting every part.

I have also flushed the cooler lines, replaced both axles, wheel bearing assemblies, and radiator just to be safe.

Anyways, on to the issue.... when cold, the transmission shows WAY over filled at the dipstick (yes, I know that you are supposed to check it warm). When warm, fluid level is normal and everything works fine, all four gears, shifts firm when it should, temperature is great.

However, God help me if I try to drive it when it is still cold. Fluid level is high at dipstick, torque converter acts like it is not full, slipping in all gears, does not want to engage properly, sometimes it will work, but it is intermittent.

My only thoughts are:

1. the filter seal felt VERY loose when installing the filter seal, but tight around filter. Could a leak here cause these symptoms?

2. When replacing the bushings, the rear coast drum bushing was WAY too tight and I could not fit it on, so I used some 600 grit paper to remove enough for it to fit. It felt great when I installed it, but if I messed up the clearances, could this cause fluid loss to the pan?

3. Maybe something entirely different that I have not thought about?

Anyways, I'm hoping you smart people here can help me out with this one. It's a pita to wait till it gets warm, but then, am I starving the transmission of fluid and doing damage...?

Did you air test all your clutch packs? It's pretty easy to hurt one on the way in and testing is key.
Coast bushing.. hmmm I don't see that being a fluid issue. Yet..it should never be too tight. That's very odd
Did you rebuild the valve body or have it done? If the checkballs aren't in the right places, that could be an issue.
You say it came out of a 2000, but what did you put it into? If changing the fittings on the outside, you could put in a non check ball fitting. That is for drain back.

Thanks for the reply BillBooost37. I did air test all clutch packs after rebuilding all of them and they checked out. If I damaged the clutch packs, wouldn't it not shift at all even when hot?

I did "rebuild" the valve body in that I disassembled it completely, cleaned and inspected all valves and bores (didn't have access to vacuum checker equipment) and updated some valves (sonnax I believe).

I'm 99% sure I put all the check-balls back in the right place (and did so with assembly lube so they would stay until final assembly).

It came out of a 2000 grand prix gt and went into a 2002 grand prix gt (pretty sure they are the same? The numbers matched closely)

Ironically, I did indeed put a non-check ball fitting on at first, then immediately put on the right one after one drive. (was hoping that this was the answer)

I highly doubt that I switched the cooler lines, but if I did, I don't think that would change anything... or would it...? I have very little knowledge about the actual fluid flow of this transmission.

As an update, just so you know what I'm looking at, I've attempted to link the dipstick running and sitting. I say "running" and "sitting" because I finally checked what happened when I let everything get up to temperature and then turn it off and check after about 5 minutes at rest. These are the results (hopefully they are good enough to see):

http://i.cubeupload.com/2ObEJ8.jpg

http://i.cubeupload.com/r7q0He.jpg

Also, I have the ability to display and capture all sorts of transmission data, but have little idea what I'm looking at...

As far as I can tell, operating temperature is 94 Degree Celsius... not sure if that's normal
Shift time for all of them is under .20 with an average of .15 for all gears
I can see the gears shifting

One curious thing that I forgot to mention. Usually the "slipping" (sounds like a rattling grinding noise) happens at very low rpm while trying to go up a hill (right by my house and my driveway is steep). I have an bad exhaust leak which is causing P0420 code and I have yet to get a CASE learn (scheduled for this weekend) so it's running a bit rough especially at low rpm's (lower than 1000) and getting very bad mpg. Not sure if this is a factor but it's worth mentioning.

Noob moment... all it was was the abs/traction control module issue.... right front wheel speed sensor is reading all over the place and ABS light is on, so I assumed it was off. Turns out, every once in a while it would randomly turn back on and engage traction control. THAT was the sound of "grinding gears" and not being able to go into fourth up hills (makes sense).

Anyways, fixed exhaust leak (loose clamp... lol), new o2 sensor, took it in to dealer for CASE learn and he said that it was the best running 3800 he'd ever seen and that it didn't need it! (Fuel trim was 0% error and absolutely no codes whatsoever)

Lesson to be learned: before you jump to conclusions or assumptions (or drop the pan...) fix your other problems (within reason) and think logically....

Originally Posted by wstefan20

when I let everything get up to temperature and then turn it off and check after about 5 minutes at rest.

Wait a second. Either I'm reading what you wrote incorrectly or you are checking it wrong. You check trans fluid with the engine RUNNING. I personally don't bother with up to temp or not as it hasn't had a huge effect on level in my experience. If you are not checking it running, your level will be messed up and causing your issue.

True... unfortunately for me, I broke my cardinal rule and had a mechanic look at it, and ensured that it should be lower when cold and that he thought it could have something to do with it.... yeah.

Embarrassing, but I'm glad that I have a $100-$200 problem than a several thousand dollar problem and installation headache again! I'd rather my pride be hurt for misdiagnosing ABS rather than for ruining a transmission rebuild! Hopefully someone can learn from my mistakes though.

Wait.. so it was fluid level?

You check engine oil with engine off, and if you are just learning..it's understandable. Hopefully the level is all that was wrong. If so.. like you said, you learned the hard way and it was cheap. That's not the usual!

Actually, I assumed the fluid level and the strange noises were linked after a mechanic told me so.... lol and hence why I rebuilt my own engine and transmission (need to start a thread on that, might help someone)!

The ABS module is toast and was randomly engaging, causing "grating noise". I was hoping it was just the hub or the wiring, but I have new hub and ran new wire all the way to the module. Verified signal was reading wrong with scan tool (easydiag is the best tool in the world). So I'll be sending that out for repair. thanks for helping me with the fluid level though guys!

So it was a bit off?

You could say that... the left front speed sensor fluctuates in park from 0 mph to 20 mph on and off, turning off system and showing dic for abs with code for that speed sensor.
went to inspect wiring, and the ground wire literally fell apart in my hand like dust! blown out about a foot. Replaced with brand new hub.

I just decided to replace both the wires all the way back to the connector. That's when I came across the real problem....

Identical behavior to before, fluctuates, usually off, but will turn on every once in a while (aka cue grinding noise)

So I take off the connector and this is what I see (P.S. this is AFTER I attempted to cleaned them, and they look worse in person)....





so what does the engineer in me do....?



so needless to say, I think I'm in need of a new module.... I think I'm just gonna have fun and see if I can't take this thing apart and repair it though... I feel a write-up coming on!

FINALLY RESOLVED!!!

Still procrastinating about the abs module, but as an update, the noise came back, but different than the abs sound. I spent weeks trying to figure out what it was and why it was happening. I have all the services and receipts from the owner and noticed that the brake master cylinder had been replaced. Thought it was odd when I saw it, but didn't pay it any mind.

A hint I got from someone regarding possible transmission noises is to put in park or drive and with your foot on the brake give it some gas (only for very short spans or you could damage your transmission) and see if the noise is present.

Everyone kept saying engine mount, but I just replaced all of them!

Then out of the blue my engine started smoking at idle (or so I thought). Checked for leaks and found what I thought was oil on the rear valve cover so I assumed the gasket failed. Ended up replacing the valve cover, gasket, and upgrading to CS144 alternator while I was at it. After all that it STILL was leaking!!!

Then things started clicking. The smoke smelled sweet, not at all like oil, my oil level was stable, the fluid didn't smell like oil, and remember the master cylinder? Had a friend press on the brake when the car was running and tada! There was a pinhole leak coming from a brake line that had been haphazardly replaced WAY too close to the exhaust manifold. Turns out, they used compression fittings too! And a shop did this work to boot!!! Charged this lady $750 for the whole job!

Needless to say I was mad that I hadn't thought to check this BEFORE I replaced all those parts... Once I had replaced the brake line PROPERLY with double flare fittings and unions and bled the brakes, the noise was GONE! It was the brake line hitting the exhaust manifold the whole time! (not scary at all...) I'm just glad I figured the leak out before my master cylinder went dry! I'm going to draw the conclusion that this happened before and caused the master cylinder to be damaged as a result (or recommended replacement just because they knew they could rip a customer off).

Moral of the story: If you hear the sound of hooves in the distance, think ZEBRA!!!!