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HELP! I'm an idiot! (transmission probs)

kevin-design

Well-known member
Joined
Jul 11, 2003
Messages
85
Location
Charlotte, NC
Corvette
1992 Black convertible LT1
Ok, I made the most embarassing mistake of my career yesterday while frantically racing around to auto parts stores in my quest to do my very first transmission swap. I'll cut the misery (the major part of this story) out and tell you the problems. I haven't slept yet so sorry if this is a little fragmented-
Anyway, so the big mistake is that I grabbed the first quart bottles of mobile 'transmission fluid' that I saw at the store. Turns out that it was actually 'Automatic transmission fluid'. So it took about two quarts of fluid before I realized that I was putting ATF in my manual 6 speed.
Now what?
Because I had to move my car by this morning (blocking a bay at work), I did start it and happily, it moved when I wrestled it into gear (very difficult). All I drove was backwards and then forwards into a parking space- maybe 30 seconds of drive time. It still has ATF in the trans. How big of a problem is this and how do I flush/replace the fluid- and with what recommended oil?

Secondly, the clutch pedal goes to the floor now with very little effort. I really don't think its engaging the clutch at all. There is/are no apparent leaks in the cylinder, and all the linkages seem to be in good shape. What's the problem with that?

Thanks for any help!
-kevin
ps. this is a '92 LT1 convertible.
 
Drain the ATF and replace it with either the recommended GM lubricant or Red Line MTL. As long as you drain it, you don't need to flush it.

Driving the trans with ATF in it for such a short time, as long as it did not sustain high load, will in no way be detrimental. In fact, other manuals, notably the T56 in C5s and C6es, use ATF as the factory lubricant. It probably couild be run for a while in a ZF with no problems so, again, don't worry, you haven't damaged your gear box.

As for the clutch, bleed the system per the service manual, then road test.
 
Whew! thanks Hib- I figured it wouldn't have much chance to be damaging since its just another lubricant. Still feel pretty silly about making that mistake though. I'm wondering if thats what was causing the shifting to be so very difficult? I doubt it- I'm taking a break to sleep and clean up before I get back into testing it out. Here's some more questions for you- I kept my '92s bellhousing in there since the bolts still lined up and I figured that would fit the engine better. I believe the '92s was magnesium and the '90 bellhousing was Al (I replaced my failing clutch/trans with a used unit from a '90 vette with 35k). It seemed that the mag one had improved cooling as well. Hope that didn't mess anything up. The only other difference I noted is that my connector no longer plugs into the 1990 speed sensor gearbox. I wonder if I can just splice the wires into the sensor on the '90 or get the proper connector and it will work accurately.

That's a job I hope to never do again!
thanks!
-kevin

Oh- one more q: The driveshaft at the rear just as it exits the seal of the trans now extends about .75" or so where you can see the smooth shaft material. Is that normal? I'm talking about between the u-jjoint and the back of the trans. I spent probably 3 hrs just trying to get that infuriating Aluminum C-channel surriounding the drive shaft in place. I wonder if that changed anything?



Hib Halverson said:
Drain the ATF and replace it with either the recommended GM lubricant or Red Line MTL. As long as you drain it, you don't need to flush it.

Driving the trans with ATF in it for such a short time, as long as it did not sustain high load, will in no way be detrimental. In fact, other manuals, notably the T56 in C5s and C6es, use ATF as the factory lubricant. It probably couild be run for a while in a ZF with no problems so, again, don't worry, you haven't damaged your gear box.

As for the clutch, bleed the system per the service manual, then road test.
 
One more q:

I was just going to go bleed my clutch and I was wondering about what to fill it with (if necessary). I got the dot 3 brake fluid info from another post, but then a posted mentioned that 'since the bleed valve was mounted on the bottom' that the bubbles float up. That seemed the illogical way to mount it when I installed my slave cylinder and so I put the valve facing up (so I could bleed bubbles out of course!). It has only two bolts in a diamond pattern so it can be mounted either way. The linkages aren't in the way of anything now. Did I just re-design an improvement into the system or do I have to go out and flip it over to the original position?
Thanks!
-kevin
 
How's it driving with your slave upside down? The bleed valve should be facing down. The slaves in these cars (some will argue) are very easy to bleed. I'd turn it around and re-bleed. (put the car on level ground, open master reservoir cap and slowly depress the clutch pedal. If the slave is in good shape you will see the bubbles rising out of the line. When the bubbles stop your done.) I can bleed my '95 in under 10 mins.
 
kevin-design said:
Whew!
(snip)
It seemed that the mag one had improved cooling as well. Hope that didn't mess anything up. The only other difference I noted is that my connector no longer plugs into the 1990 speed sensor gearbox. I wonder if I can just splice the wires into the sensor on the '90 or get the proper connector and it will work accurately.

That's a job I hope to never do again!
thanks!
-kevin

Oh- one more q: The driveshaft at the rear just as it exits the seal of the trans now extends about .75" or so where you can see the smooth shaft material. Is that normal? I'm talking about between the u-jjoint and the back of the trans. I spent probably 3 hrs just trying to get that infuriating Aluminum C-channel surriounding the drive shaft in place. I wonder if that changed anything?

I'd try putting the VSS out of the 92 transmission you took out into the 90 trans. you put in. In lieu of that, i suppose it's possible to splice the wires and connectors.

driveshaft issue, I'm not quite sure what you are asking. There should be no problem with driveshaft length.
 
Well, I'd try just swapping the VSS but all the fluid I changed out ($12/quart!! for the BWM stuff) will spill right out the hole if I try, and it was SUCH a pain to get in! Here's an update :(
After the swap, I had a fun weekend driving it all over with a great feeling new trans/clutch. Everything seemed peachy till tuesday. Now whenever I press in the clutch pedal, I hear a grinding noise. The gears and clutch and all that still hold and drive fine, and if I let the synchros do the work I can smoothly shift without depressing the clutch and still drive the car okay.
Due to my new rule of 'one trans swap per lifetime' I'm going to take the car in to have somebody more experienced figure it out. It sounds like a problem with the fork engagement of the throwout bearing. I wonder what I messed up? It was fun while it lasted!
Thanks for the help!
ps. The upside-down slave cylinder seems to be working fine after I used the method described here to pump about 300 times and get rid of the air.

p.p.s. on the driveshaft issue- d'ya know how half of the U-joint that slides into the transmission is able to slide along its axis? Well, I was just wondering how far it should be able to slide when everything's correctly installed. I was concerned because I could see more of that shaft than I might have expected, meaning that I was worried that that component might be sticking too far out of the transmission.
 

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