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So I am very disappointed right now, drove my wife's corvette to a car show this weekend and after we left had transmission issues - must mention the car is a 05 Z51 Auto car with only 93K miles. This car RARELY gets driven hard as my wife drives it to work everyday and drives like an old lady - she just wants the sporty car before we have kids.
So we are cruising along and here a loud pop - I actually thought we hit something in the road - then all of a sudden the rpms increase like the car is in neutral.. I drop it down to third and we drove on home, messing around with the car in the drive way everything works normal except for drive revs like neutral. Park, Reverse, Neutral, 3rd, 2nd, 1st all act normal and the car will move in those gears. Also noticed on the way home after the pop there is a noticeable shudder when shifting from 1st - 2nd.
I am not sure what is going on here and hoping some of you guys can help me out.. I have a full service shop here at my house - I am pretty sure it is leading to a trans rebuild unfortunately, I am going to get the car on the lift tonight and drain the trans fluid and see how it looks.
I'm sure smarter people will be able to help more but I'm going to take a stab at it...
Possibly the 2-4 band anchor pin broke. The band is applied in 2nd gear and in 4th. See how far you can push in the 2-4 servo cover on the passenger side of the transmission. (Green arrow in picture)
I'm sure smarter people will be able to help more but I'm going to take a stab at it...
Possibly the 2-4 band anchor pin broke. The band is applied in 2nd gear and in 4th. See how far you can push in the 2-4 servo cover on the passenger side of the transmission. (Green arrow in picture)
I will have it on the lift and will check on the servo cover and report back
I did not think the forward sprag assembly was engaged in 4th?
That is correct. With a broken forward sprag, the car will not move with the shifter in [D4]/[OD], but will only move if you start in [D1] and then manually shift to higher gears as the speed increases.
Ok so I pulled the servo, there are two seals that are split - I am not sure if that is how they are supposed to be or not - I am going to stop by GM parts dpt after work and look at their diagram. I have a new servo sitting here at the house but I really would prefer to go with an OEM part - the new servo has actual O-rings and none are split.
Also this is in a vette, I cant get the "main servo" out b/c its too close to the frame. Thinking about just replacing the seals and putting it back together but 98CayenneT/A mentioned the band anchor pin, is that in the servo housing or is that internal?
Any help yall can provide would be awesome. I am attaching some pics.
Ok so I pulled the servo, there are two seals that are split - I am not sure if that is how they are supposed to be or not - I am going to stop by GM parts dpt after work and look at their diagram. I have a new servo sitting here at the house but I really would prefer to go with an OEM part - the new servo has actual O-rings and none are split.
Also this is in a vette, I cant get the "main servo" out b/c its too close to the frame. Thinking about just replacing the seals and putting it back together but 98CayenneT/A mentioned the band anchor pin, is that in the servo housing or is that internal?
Any help yall can provide would be awesome. I am attaching some pics
The Factory servo seals are "Scarf" Cut Teflon, You should have checked the Clearance with a Pry Bar before removing the Servo Cover, If the Anchor slot in the Band was pulled through.....It would have a mile & a half of travel.
A Broken Anchor Pin would be very unlikely on a stock trans.
In your original post......You stated the car will not move with the shifter in D4 while sitting still but works in all other ranges?? If so.....That has nothing to do with the Band, 2nd Servo or 4th Servo.
If it was the Input Sprag.....You would have the SAME symptoms in D3 taking off from a stop, Unless modifications are done to make the Overruns come on in D3 with the trans in 1st gear.......But it wouldn't "Neutral" on you in 4th gear because (Like already stated) The Input Sprag overruns in 4th.
Did you check Shifter Cable adjustment? Broken Adjuster at the Shift Arm?
A misadjusted Manual Valve can & will cause the Trans to BURN DOWN.......AFTER symptoms just like yours.
An even easier check......Put the Shifter in D4, With the engine off, If the engine cranks.....The Trans is in NEUTRAL!
The Factory servo seals are "Scarf" Cut Teflon, You should have checked the Clearance with a Pry Bar before removing the Servo Cover, If the Anchor slot in the Band was pulled through.....It would have a mile & a half of travel.
A Broken Anchor Pin would be very unlikely on a stock trans.
In your original post......You stated the car will not move with the shifter in D4 while sitting still but works in all other ranges?? If so.....That has nothing to do with the Band, 2nd Servo or 4th Servo.
If it was the Input Sprag.....You would have the SAME symptoms in D3 taking off from a stop, Unless modifications are done to make the Overruns come on in D3 with the trans in 1st gear.......But it wouldn't "Neutral" on you in 4th gear because (Like already stated) The Input Sprag overruns in 4th.
Did you check Shifter Cable adjustment? Broken Adjuster at the Shift Arm?
A misadjusted Manual Valve can & will cause the Trans to BURN DOWN.......AFTER symptoms just like yours.
An even easier check......Put the Shifter in D4, With the engine off, If the engine cranks.....The Trans is in NEUTRAL!
Yes I checked the play on the servo cover with a pry bar, it went in about 1/2" to an 1"
I did some reading on the servo and saw several people saying they had no 4th gear and replaced the servo assembly and then regained 4th gear so I figured I would give it a try, Id love to replace the assembly but not enough clearance to get it out.. Still haven't replaced the seals just yet, had a busy weekend. Once I stick the servo back in I will check on the shift linkage like you mentioned, I never thought about trying to crank the car with the shifter in D4 - good Idea.
Yes I checked the play on the servo cover with a pry bar, it went in about 1/2" to an 1"
I did some reading on the servo and saw several people saying they had no 4th gear and replaced the servo assembly and then regained 4th gear so I figured I would give it a try, Id love to replace the assembly but not enough clearance to get it out.. Still haven't replaced the seals just yet, had a busy weekend. Once I stick the servo back in I will check on the shift linkage like you mentioned, I never thought about trying to crank the car with the shifter in D4 - good Idea.
If you were able to push the servo cover in that far the 2-4 servo is not your problem, your band is. You should of only been able to push that cover in a quarter inch at the very very most
Yes I checked the play on the servo cover with a pry bar, it went in about 1/2" to an 1" .
Wow, if you measured that right then your band is snapped or anchor pin broken off.
The normal clearance is about 1/16" to 1/8" and after 3/16" you will start loosing 2nd and/or 4th gear due to band wear.
Now that I am thinking about it 1/2" to 1" def doesn't sound right, It had to have been more like 1/4" but I am not sure how I would accurately measure it, its so tight against the rail.
ClineBarger - It definitely is a Neutral Situation in 4th gear - when I heard the pop it went straight to neutral situation and would only rev, I had to manually pull the shifter down to third to engage forward motion. I do however have a noticeable shutter on the 1-2 shift also. I have been extremely busy and haven't been able to get the servo back together but I am off this Friday so I will throw the servo back together with new seals and test the shift linkage theory, if neither of those I am going to start removing the transmission and find a reputable shop to rebuild it.
I am surprised I haven't heard a vendor chime in yet, I hope I don't have to but definitely will be looking for someone to rebuild it if that's the case.
Clinebarger: It's great to have an expert like you helping out here; you just have to get used to "reading between the lines" and not taking every OP's post completely literally. I'm sure if you drove the car you could figure it out instantly.
maroon88iroc is posting more clearly than most, but there obviously are inconsistencies which are confusing everyone including GMCSIERRA5.3.
In any case it sounds like something is seriously broken.
maroon88iroc: if you include your city/state we can refer you to the nearest sponsor or one of the non-sponsor builders might PM you.
The sponsor/vendors rarely chime in because they are burnt out doing so after many years and appreciate that I try to help out. I in turn appreciate when experts like Clinebarger help you; hopefully he won't burn out too soon.
I got about an hour to mess around in the shop last night, with the servo cover pulled I can push the servo in over a 1/4" for sure. the fluid behind the servo was a little brown but I went ahead and pulled the pan last night and the fluid is very very dark brown, not much red sheen to it at all - so I am assuming it will need a rebuild.
I am really honestly blown away at this transmission needing a rebuild, it only has 90k miles on it and has not been driven hard.. it is the 4l65E so I've read they are a decent bit stronger than the 60e.
The Servo Cover has to be in place to measure Band Clearance.
ATF loses the Red Dye after awhile, If the fluid has never been serviced.....It will be pretty dark. If there isn't a lot of clutch debris in the pan......Don't be so quick to condemn your trans.
09-19-2016, 08:27 AM
2005 Corvette 4l60e Loud pop now no 4th gear 
