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L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

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Old 07-23-2013, 12:52 AM   #21
kenholio
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116k trans has always shifted fine with no issues
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Old 07-23-2013, 04:12 AM   #22
Cliff Harris
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Quote:
Originally Posted by kenholio View Post
No gauge for the trans temp, only oil and water temp
You press a magic combination of buttons to get the dash to display the trans temp. it's sorta like displaying the trip odometer. Like I said, my C6 will do it -- don't know about your car.
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Old 07-23-2013, 04:25 AM   #23
desertmike1
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Stick a GoPro under the car, and take it for a drive..
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Old 07-23-2013, 10:22 AM   #24
Churchkey
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This probably does not apply to GM cars, never encountered a converter drain plug on GM's. If the converter has a drain plug insure that it is tight.

The converter may be fractured @ the weld line. Heat expansion + centrifugal force = a leak @ higher rpm.

A leak will never be found if 2 quarts of fluid have been dumped under the car, to much mess.
Clean the trans thoroughly, wrap a white rag around the dipstick fill & if the trans has a vent put a rag around it.

With the trans up to temp make a short high speed run & check for a leak. You may need to lengthen the speed run each time until the leak reappears.

If unable to determine the leak source clean the trans & paint it flat black. Follow the oil track to the source.

Last edited by Churchkey; 07-23-2013 at 10:25 AM.
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Old 07-23-2013, 12:33 PM   #25
kenholio
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Quote:
Originally Posted by Cliff Harris View Post
You press a magic combination of buttons to get the dash to display the trans temp. it's sorta like displaying the trip odometer. Like I said, my C6 will do it -- don't know about your car.
Wish there was a magic combo for this
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Old 07-23-2013, 07:26 PM   #26
kenholio
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Going to the shop in the morning to check transmission and factory transmission oil cooler, will update when I know.
What is the factory capacity for the factory oil cooler ?
I will need to double that value if I bypass it
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Old 07-25-2013, 06:46 PM   #27
kenholio
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So he says the main seal needs replaced and that it only leaks in OD when it makes the most pressure ?? Though reverse made the most pressure, guess its second opinion time
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Old 07-25-2013, 11:22 PM   #28
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These are the pressures I measured on my MD8 Corvette 700r4 with a 0.500" boost valve (stock is 0.472", as I recall, so these pressures are higher):

Code:
     Idle or Min TV
 P        90 PSI
 R       130    
 N        90
OD        90
 D        90
 2       230
 1       230
As you can see, 1st and 2nd have the highest pressures. This means putting the shift lever in the 1 or 2 position, not when the trans downshifts while in D or OD.
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Old 07-25-2013, 11:26 PM   #29
kenholio
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thanks for the numbers, mine only leaks in OD at speeds over 60, picking it up tomorrow, will post what he said needs to be done to her.
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Old 07-26-2013, 01:55 PM   #30
kenholio
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Front pump seal leaking, leaks more in OD when the torque converter dumps the fluid out.
ATP Part # CGS31 Overhaul Kit $ front pump seal and bearing and fluid $118, labor $800
Time for google searches, can's be that hard to do it myself
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Old 07-27-2013, 06:10 AM   #31
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Quote:
Originally Posted by kenholio View Post
Front pump seal leaking, leaks more in OD when the torque converter dumps the fluid out.
ATP Part # CGS31 Overhaul Kit $ front pump seal and bearing and fluid $118, labor $800
Time for google searches, can's be that hard to do it myself
That has nothing to do with OD. It's the TCC (Torque Converter Clutch) that dumps fluid when it engages. It works backwards from what you would expect. Fluid pressure holds it OFF and the fluid is bypassed to engage the TCC.

You have to take the trans out. Have fun. I've done it 4 times. It's one of the jobs I really hate on this car. It's a lot of work and takes a lot of time.
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Old 07-27-2013, 10:55 AM   #32
kenholio
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so is there something i will also have to do to the tc ?
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Old 07-27-2013, 10:56 AM   #33
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I had the same problem. I changed the front pump seal myself, it leaked again when hot. I had the transmission professionally rebuilt. It leaked again a year later, right after the warranty ran out.
The seal that leaks is an o-ring between the pump and case.

Click the image to open in full size.
For me the trans would leak only on the highway after I've been sitting in traffic. My guess is that the radiator and trans would heat up in traffic. When I went on the highway the fluid would cool, cooling the pump, but the case would stay hot. Increasing the pump to case clearance causing a leak.

I added an external trans cooler and haven't had the problem again for over 7 years.

Does yours leak only after getting very hot?
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Old 07-27-2013, 11:03 AM   #34
kenholio
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Let it run in park for a hour yesterday and no leak, went for a ride and then it leaked after a high speed run in 1st and 2nd. Wondering if i need a transcooler, but that wont fix the problem by itself ?
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Old 07-27-2013, 11:10 AM   #35
QuickGlass
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Would yours leak if you didn't let it idle for an hour?
If it's cold and you drive on the highway, will it still leak?
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Old 07-27-2013, 11:26 AM   #36
kenholio
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Quote:
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Would yours leak if you didn't let it idle for an hour?
If it's cold and you drive on the highway, will it still leak?
no leak at idle, hot or cold.
have not tried cold on highway, will try that today.
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Old 07-27-2013, 03:17 PM   #37
kenholio
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Quote:
Originally Posted by QuickGlass View Post
Would yours leak if you didn't let it idle for an hour?
If it's cold and you drive on the highway, will it still leak?
Drove a mile to get gas, jumped out on the main road and opened her up for a quick high speed run, no leaks. If I do the same thing after the engine has warmed up it will blow out oil everywhere.
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Old 07-28-2013, 12:14 AM   #38
QuickGlass
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Could be a bad o-ring from age or the trans is just getting too hot.
You could try installing an external trans cooler, fairly cheap and easy to install. Plus good for the trans.
If you want to change the o-ring yourself, trans removal is a bit of work.
When removing the pump, keep the trans standing on the tail. Don't lay it down.
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Old 07-28-2013, 12:39 AM   #39
kenholio
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Quote:
Originally Posted by QuickGlass View Post
Could be a bad o-ring from age or the trans is just getting too hot.
You could try installing an external trans cooler, fairly cheap and easy to install. Plus good for the trans.
If you want to change the o-ring yourself, trans removal is a bit of work.
When removing the pump, keep the trans standing on the tail. Don't lay it down.
Yeah adding a external trans cooler can't hurt.
Why not lay down the trans ? If I pull it, I might as well throw a rebuild kit in it vs just replacing pump seal o-ring.
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Old 07-28-2013, 10:03 AM   #40
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If the trans is on its side when the pump is removed, the input shaft will slide out and the bearing at the end will move out of position.
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Old 07-28-2013, 10:03 AM
 
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