4L65E corvette servo upgrade, now no 2nd gear

[AltxF4]

So I have had the Corvette servo parts sitting around for a while now, and I figured I would install it while I was doing the trans fluid and filter change. I got it all done and installed, and now I do not seem to have a 2nd gear... I still have 4th though. What the heck did I do wrong?

Thanks in advance.

 

[HiHoeSilver]

So I have had the Corvette servo parts sitting around for a while now, and I figured I would install it while I was doing the trans fluid and filter change. I got it all done and installed, and now I do not seem to have a 2nd gear... I still have 4th though. What the heck did I do wrong?

Thanks in advance.

You split the o-ring. Probably the blue one.

 

[AltxF4]

You split the o-ring. Probably the blue one.

Hmmm... make some sense. Hope that is an autozone part... I will pull it off tomorrow. Any tricks to getting it in without killing o-rings? the videos I saw (the few done in a vehicle) it seemed like they just shoved the thing in, and pied the cover to get the snap ring in.

 

[HiHoeSilver]

Hmmm... make some sense. Hope that is an autozone part... I will pull it off tomorrow. Any tricks to getting it in without killing o-rings? the videos I saw (the few done in a vehicle) it seemed like they just shoved the thing in, and pied the cover to get the snap ring in.

I'm not sure about replacement, but I'll bet if you pull it apart, you'll clearly see what's wrong and know what to be more careful with next time.

 

[AltxF4]

I'm not sure about replacement, but I'll bet if you pull it apart, you'll clearly see what's wrong and know what to be more careful with next time.

Alright, fair enough. Now the question is will it be ok to drive it like a grandma until Monday or Tuesday when I get the new seals in (if I can't get any local over the weekend)?

 

[HiHoeSilver]

Alright, fair enough. Now the question is will it be ok to drive it like a grandma until Monday or Tuesday when I get the new seals in (if I can't get any local over the weekend)?

What's it doing? 1st to 3rd?

 

[AltxF4]

What's it doing? 1st to 3rd?

First starts out normal, but it will get to the point where it would normally shift, but will just keep increasing in revs without any speed increase. If I let off the throttle a little bit, it will then shift to 3rd, and 3rd is good, and then will shift to 4th fine. Manually moving the gear selector, 1st works as a expected, and so does 3rd. Shifting to 2nd it feels like its not doing anything, but I feel like I might be maintaining speed, but RPMs go up a lot with more throttle.

 

[HiHoeSilver]

First starts out normal, but it will get to the point where it would normally shift, but will just keep increasing in revs without any speed increase. If I let off the throttle a little bit, it will then shift to 3rd, and 3rd is good, and then will shift to 4th fine. Manually moving the gear selector, 1st works as a expected, and so does 3rd. Shifting to 2nd it feels like its not doing anything, but I feel like I might be maintaining speed, but RPMs go up a lot with more throttle.

Here's the thing, you're not gonna know exactly what you did wrong until you take it apart. I would count on being down as long as shipping is for whatever you f-ed up. Your certainly not the first one to have trouble doing this job.

 

[AltxF4]

When I installed the servo, I used the longer No groove Pin that came with the OPT kit. The pin that was in my Yukon was the middle length 2 groove pin. It was really hard to press in the cover to get the snap ring in. Could any of this Cause a problem like I am seeing?

 

[HiHoeSilver]

When I installed the servo, I used the longer No groove Pin that came with the OPT kit. The pin that was in my Yukon was the middle length 2 groove pin. It was really hard to press in the cover to get the snap ring in. Could any of this Cause a problem like I am seeing?

I don't think so. Are you sure you oriented everything the right way? I remember somebody putting the apply piston in backwards once and it gave him trouble. He put it in right, and all was well.

 

[AltxF4]

I don't think so. Are you sure you oriented everything the right way? I remember somebody putting the apply piston in backwards once and it gave him trouble. He put it in right, and all was well.

The only thing I can think of that I could have put in backwards would be the 4th apply piston... but I don't think I did. 2nd apply piston and pin was installed with steel cover facing in towards the trans. When I disassembled the the old 2nd apply piston, there was only 1 spring in there. There are some photos online I see 2 springs...

 

[Jeff Groves]

Did you check the travel distance before installing the long pin?

 

[AltxF4]

So HiHoeSilver was on the right track. It ended up that I pinched the large split teflon seal on the 2nd apply piston. The OE Split telfon seal that came off with the old servo was in really good condition, so I am re-using it until I can install the new seal next weekend. To keep the teflon seal from pinching, I really filled the seal groove with petroleum jelly before placing the seal in the groove. Install is much easier the 2nd time around.

Jeff, yes I did old pin was right under 1/8" and new one puts me a little over 1/16"

Now everything is working, and man it sure makes a difference!

 

[HiHoeSilver]

So HiHoeSilver was on the right track. It ended up that I pinched the large split teflon seal on the 2nd apply piston. The OE Split telfon seal that came off with the old servo was in really good condition, so I am re-using it until I can install the new seal next weekend. To keep the teflon seal from pinching, I really filled the seal groove with petroleum jelly before placing the seal in the groove. Install is much easier the 2nd time around.

Jeff, yes I did old pin was right under 1/8" and new one puts me a little over 1/16"

Now everything is working, and man it sure makes a difference!

Good job.

 

[the blur]

I have the servo kit. Never used it. Sold my truck.
I'll let it go cheap...
PM me

 

[HiHoeSilver]

I have the servo kit. Never used it. Sold my truck.
I'll let it go cheap...
PM me

Which kit do you have?

 

[Spoolin]

Pardon my ignorance, but I’ve read a couple topics about these corvette servos, what exactly do they do and why to do them?

Thanks

 

[HiHoeSilver]

Pardon my ignorance, but I’ve read a couple topics about these corvette servos, what exactly do they do and why to do them?

Thanks

It will firm up the 1-2 (& 2-3) shifts and have more holding power to stay in gear longer through the power band. Less slipping =less wear. Also, noticeably more fun when you're getting on it.

One of, if not the best ~$20 mods, imo.

 

[Jeff Groves]

It will firm up the 1-2 (& 2-3) shifts and have more holding power to stay in gear longer through the power band. Less slipping =less wear. Also, noticeably more fun when you're getting on it.

One of, if not the best ~$20 mods, imo.

Well stated.
I started modding this line of trannies way back in what '82 or '83 when the 700R4 came out?
I was the first in my area to have one installed in a '75 Camaro with a Duel Nox system.

 

[Tonyrodz]

Pardon my ignorance, but I’ve read a couple topics about these corvette servos, what exactly do they do and why to do them?

Thanks

I have it in my rebuilt. Listen to the shifts.

Those are some firm ass shifts!