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I rebuilt my 4L60E, ran fine two days and same problem reoccured, no third gear Help

 
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raydium raydium
New User | Posts: 3 | Joined: 02/07
Posted: 02/11/07
08:35 AM

I am totally stumped, I have a 94 full Size Blazer 4WD with a 4L60E.
It had 250,000 miles on the car and had tranny problems. It will run through first and second but when shifting to third it acts like it is dropping into neutral. It was an old car and I wanted to give it to my son to drive to school. I decided to rebuild it myself. bought a DVD on the rebuild and ordered parts and rebuilt it. Everything went fine with everything going together according to plan.
After getting it all back together it ran fine for two days. When I hit the freeway and got it up to about 65 for a few miles the thing dropped out of gear and would only go into 1st or 2nd but NOT third, just slipped in third.

Here's what I did on the rebuild

1994 Full size Blazer, V8 350, 4WD.

The transmission is a 4L60E; it had about 250,000 miles on it. It will go into reverse; it will shift through 1st and 2nd but when shifting to 3rd it seems to drop into neutral.
If you drop the speed back down it will shift back into 2nd. Once the problem reappeared it would not shift past second from that point on.

Parts replaced:

- Full Master rebuild kit with all Steels and Clutch plates
- Torque converter
- 1-2, 2-3 shift solenoids
- All accumulators and pistons
- Fluid Pressure switch assembly
- New spacer plate and check balls
- Replaced drum housing assembly with “The Beast”
- Disassembled Valve Body valves/springs. Cleaned and reassembled.
- Rebuilt pump

Parts NOT replaced
-          Pressure Control Solenoid ( checked proper resistance with ohm meter)

After getting it apart I found like expected (250,000 plus mile on it) the clutches and steels were worn down. Most seals and O Rings were flattened by wear.

I replaced every seal, gasket and O ring, cleaned everything in cleaning solvent, and burnished all valves and piston walls. Every hard part was cleaned and de-burred if needed. I made Air pressure checks on the clutch assembly during rebuild and everything worked. The truck drove fine for about an hour of drive time before the exact problem re-occurred. When the problem re-occurred it was the first time I had the truck up to that speed (65-70) for about five miles.

I AM STUMPED on what to do next, I tried to check vehicle code, all 12's. no error, I thought VSS bad, after reading this seems like it would effect all gears and not just third.

ANY help apprecisted
Ray  

transdoctor transdoctor
User | Posts: 74 | Joined: 10/06
Posted: 02/12/07
09:09 PM

Unforunely there is no eas yanswer just things to check. Sounds like the 3-4 clutch is not working properly or burnt. There is a Check ball capsule in the case did you check that during your rebuild? Also verify the 2-4 servo is assembled correctly. Also did you inspect the sleeve in the pump? I can spin in the bore and restrict 3-4 clutch oil. This is common on high mileage vehicles. A rebuilt pump is highly recommended.  

raydium raydium
New User | Posts: 3 | Joined: 02/07
Posted: 02/13/07
04:46 AM

Hi Transdoctor

 Do you know of anything outside of the transmission that could also cause that problem. I followed a DVD on how to rebuild the tranny. I did check the check ball in the case. I find it frustrating that after replacing all that I did I have the EXACT same problem. I would have expected that I miht have caused a new problem but surely would have caught the original problem.

 Thanks
Ray  

transdoctor transdoctor
User | Posts: 74 | Joined: 10/06
Posted: 02/13/07
03:36 PM

There are some cases were you could have an electrical problem causing this to happen. Usually this set a diagnostic code. Does the problem go away after you cycle the ignition? Are you sure it is 1st and second gears? The solenoid states for that transmission  are both on in first, B on in second, both off in third and A on in fourth. A quick check is to pull the transmission fuse. you should start in 3rd gear. This will tell if you are able to even get third.  

raydium raydium
New User | Posts: 3 | Joined: 02/07
Posted: 02/15/07
04:41 AM

Thanks Transdoctor

 That sounds like a good test to try. I will find and pull the fuse and update you on what happens.


Thank
Ray  

JayH JayH
New User | Posts: 1 | Joined: 02/07
Posted: 02/27/07
04:12 PM

Anything on this?

I have a '95 corvette that exhibited the same symptoms about two years ago. I pulled the 4l60e and performed a complete rebuild. Put it all back together and had the same exact problem. Turned out to be the pressure manifold gone bad.

Yesterday, I had the same exact thing happen. Haven't pulled the valve body yet (dreading the time and money frankly,) but am starting research again...  

Hog Rider Hog Rider
Enthusiast | Posts: 275 | Joined: 02/07
Posted: 02/27/07
06:30 PM

Pressure Manifold problems will cause your problems  along with
any  Missing  gear problems   some Do not show up on the scanner as codes  but in a Data screen you may be able to pinpoint this

no need to Pull the Valve body  as it is accessiable  just  in the pan  
Hog Rider

got_chevy got_chevy
New User | Posts: 2 | Joined: 04/07
Posted: 04/26/07
09:51 PM

Hey, Im havin the same problem. It all started after I took my 35x12.5 tires off and put some 32x10.50s on. I drove it for about 130 miles and the tranny started acting funny and the speedometer did to. Right now with the electronics hooked to the tranny I have 1st when its cold, but soon as the tranny warms up a bit I only have 2nd and when I get to about redline I have to let all the way off the gas and then it will shift up but it pretty much just shifts into neutral. Soon as I get to about 3500rpms it and let off it will shift back to 2nd. If I put the fuse to the tranny it and put it in Drive it starts off in 3rd but if I put it in 1st or 2nd it will start off in 2nd. Is this a electronic problem or just a plain tranny problem?  

Hog Rider Hog Rider
Enthusiast | Posts: 275 | Joined: 02/07
Posted: 04/30/07
06:42 PM

Have it scanned My Friend  and get back to me ,
I,m sure we can get this Straight  
Hog Rider

dfgl dfgl
New User | Posts: 1 | Joined: 03/09
Posted: 03/14/09
11:43 AM

I am running into the same problem with my 94 GMC Sierra.  It will start off in 1st  then shift to 2nd but when it should shift to 3rd, the speedometer drops to zero and it will not shift.  I pulled the trans fuse and it will start off in 3rd, I can force it through 1st and 2nd and it seems to work through all gears.  I have not gotten into 4th though.  One other odd thing, is that the parking brake light will come on after just a short time of starting up (with or without the Trans fuse in).  When you press the brake there is an odd clicking or crakeling noise (almost like a short but it could be celephane??)  Any suggestions?  

kamcoautomotive kamcoautomotive
New User | Posts: 1 | Joined: 10/09
Posted: 10/16/09
03:24 PM

do you know if Raydium ever found his problem?
I have the same problem. What I cant understand is why it does not throw a code. Because when it flares between 2-3, and then goes to something like neutral, there is obviously a pressure problem.
the pressure problem should be detected by the Pressure manifold switch, but its not. Indicating it is after that. Also, when it flares the VSS and the high Tach values should set a slip code, but it is NOT. yet every one who has this problem and here are hundreds, do not get codes. What it looks like is there is a pressure loss at the 3/4 clutch. Now these all have what has been said to be weak 3-4 clutch packs. Im not buying it. This tranny had a weak shift from 2-3 since new. Even after total rebuild it the same.I'm convinced the fluid feed to the 3-4 clutch is the issue here. Possibly a defective design in the casing circuit post of the manifold.Every time I rebuild this thing the 3-4 assembly that was complete new , looks like it was starved for fluid pressure and wears out faster than the others. I still don't get why a slip code is not set. So, did raydium find the problem. I really would like to know.
Also, I noticed that the 'b' relay has no spring force backing like the 'a'. This b relay flops in the socket. Huge pressure leak spot. piss pore design on the b relay.  

latergator latergator
New User | Posts: 1 | Joined: 10/09
Posted: 10/20/09
10:49 AM

4L60E slips out of gear after driving 55mph for 20 minutes to an hour of driving on the highway.

Heres the details:   93 K5 4x4 Blazer.  I have had this truck for about 14years.  The vehichle has been very well maintained.  When I have a problem I fix it.  The transmission was rebuilt by a reputable transmission guy at a reputable company about 5 years ago.  The transmission was rebuilt at 165,000 miles.  I know have 248,000 miles on the rebuilt tranny.  When the tranny was rebuilt all new current updates at the time were installed. About 2 years after the rebuild, while driving on city highways in Dallas Metroplex for  about an hour at 50 - 75mph the 3rd gear would slip (and freespin like in neutral) when I was at about 55mph speed.  Then I found that if I slowed down to about 35mph to the lower gear (2nd)and then increased my speed back up to 3rd gear everything was back to normal and worked fine, like nothing was wrong and the truck would run and shift fine.  This would do this usually after a long time of highway driving. It wouldnt do it all the time.  Took it to the transmission shop that built the tranny and they could never find any codes or duplicate the problem. This went on for 5 years or more.  Now the problem has progressively gotton worst over the past year.  The tranny filter and fluid were replaced on a yearly basis.  I recently had a different company, a chevy dealer in dallas, a specific transmission guy - friend of a friend at the chevy dealer look at the problem.  He said he couldnt see any codes and that there was no indication of anything internally being burnt up.  He said its common for 3and 4 gears to fail in these units but he said he didnt think my 3and 4gears were burnt up because fluid smelled and looked good.  He said it could be mechanical????   I am electromechanical degreed engineer so I usually try to fix things myself when possible.  But I also respect the expertise of a professionally trained tech so thats why I had a professional do the rebuild.  But before I spend 1000 to 1400 to have this rebuilt again, I would like to try to fix this myself if it happens to be something simple that I could do.  I talked to another Chevy transmission tech with 33 years of experience and he said that he could rebuild it for me for 350 bucks.  But before that, he said I could try to replace 1-2 and 3-4 shift solenoids.  should I also replace the pressure manifold?  Anyone have any ideas???  or other recommendations?  Should i remove and polish or clean the spools in the valve body??  what else should i replace if I drop the pan??  I have seen videos on u tube how to remove the valve body and to replace parts on it.  Seems pretty easy. Of course you have to be super detailed and careful not to scratch or score any surfaces, understood.  I currently repair CNC machines as a living and have 25 years experience repairing industrial production equipment so Im comfortable trying to do some repairs.  any help or advice would be greatly appreciated.  Thanks

MC  

evodave evodave
New User | Posts: 1 | Joined: 10/09
Posted: 10/26/09
08:06 AM

so i picked up a 1999 sonoma with the 4.3 L  car has 130,000 miles.  It has a slight issue where once every few times backing up it will clunk hard. Additionally for no reason on the highway in 4th it will bang /clunk a bit once in a while. Does this sound like something an additive or flush would fix?  any ideas?  everything else works fine.
thanks  

vnm02 vnm02
New User | Posts: 1 | Joined: 10/09
Posted: 10/27/09
10:03 AM

Hope this helps someone, it helped me!!
Just Google "4l60e 2-3 shift flare" and its usually the first hit that comes up if you want to see the images etc....

In past TASC Force™ Tech Tips, I have
stressed the benefits of testing electrical circuits
by measuring amperage draw. I have also commented
that finding new information adds
pieces to the puzzle and helps to bring the
whole technical picture into better view. This
month’s topic is an example of using amperage
draw testing to uncover an additional cause for
2-3 shift flare on 4L60-E transmissions.
In the past, hints and suggestions for causes of
4L60-E 2-3 flare have invariably been centered
on problems inside the transmission. Some of
the most common causes are low line pressure
and internal leaks of 3rd gear oil. More recently,
information has come out about input housings
with the 3-4 piston feed hole mismachined
in the lip-seal area. Another contender
that can now be added to the list of possible
causes for 2-3 shift flare on a 4L60-E is a
bad computer.
This month’s problem vehicle is a 1998 GM
truck with a flare on the 2-3 shift before and
after overhaul, with no trouble codes. The shop
installed a second valve body with all solenoids
but it didn’t help. Line pressure was normal in
all ranges as well as when the flare occurred.
When a new computer was tried, the problem
went away. The puzzling thing was that line
pressure was the same with both computers, so
what was causing the flare? One clue was the
“B” solenoid data on the scanner would sometimes
flash “short” when the problem occurred.
This is when the amp meter came out to assist
in diagnosis.
Most modern DVOMs give the option of
checking current (amps). If you have never
done amperage draw testing, I encourage you to
learn more by checking the manual for your
DVOM, reading past Tech Tips (Transmission
Digest, November 2002) or other recent tech
articles about the newer mini clamp-on inductive
amp probes. Checking amperage is neither
complicated nor difficult and is often easier
than ohm tests or other more commonly performed
circuit checks. Testing circuits while
they are in operation is one of the most effective
ways of confirming a good circuit. Once you
have become comfortable with the concept, it
becomes a powerful diagnostic tool.
For this vehicle I tapped into the transmission
+Positive power supply by replacing the ‘Trans’
fuse with the two leads of the DVOM. Now, all
power for this circuit is flowing through the
amp section of the DVOM and the circuit
remains protected by the internal fuse in the
meter. Figure 1 shows the set-up using a conventional
DVOM. With the key on and using a
scanner with bi-directional controls, the next
step is to command 3rd gear, which turns both
“A” and “B” shift solenoids off on a 4L60-E. At
this point, zero-out the DVOM so the current
draw from any other components sharing this
circuit is canceled out and you are monitoring
only current changes you command from this
point on. Commanding 4th turns only the “A”
solenoid on, while commanding 2nd turns only
“B” solenoid on.
Using this simple DVOM set-up, we watched
the current draw change as each solenoid was
turned on and off. Although the maximum current
draw of the two circuits was almost identical,
their behavior was not. When turned off,
the “A” solenoid would drop to zero in a fraction
of a second, whereas the “B” solenoid
would take about 2 seconds to drop to zero. We
recorded the behavior using the graphing capability
of a Snap-on™ Vantage in order to get a
closer look and to show you a picture of what
we spotted on the DVOM. Figure 2 shows the
difference when the “A” and “B” solenoids were
compared. When the computer did not turn
4L60-E flares on 2-3 shift
Now what?
continued on page 2
Figure 1
Article No.: TASC Tip_11-06 Author: Gregg Nader Page 2
the “B” solenoid off cleanly, it would not exhaust its oil fast enough
and the 2-3 shift valve would move gradually instead of moving
crisply from one position to the other. This allowed the 2-4 band to
come off momentarily before the 3-4 clutch applied, resulting in a
2-3 flare.
What causes this problem inside the computer? There are no physical
contacts that open or close like in a relay. All the solenoid controls
or output drivers are solid state circuitry. It could be anything
from a decaying capacitor to a silicon chip going bad because someone
sneezed in the clean room when it was being made. I have seen
two vehicles with this problem locally, so there is a good chance there
are more bad computers out there. So, if you run across a 2-3 flare,
keep in mind the computer as a possible cause.
Thanks to Jeff Davis at Rockenbach Chevrolet and Jon Glatstein of
ATSG for their contributions to this article.
©Sonnax Industries Inc.
Figure  

gm_charlie gm_charlie
New User | Posts: 3 | Joined: 11/09
Posted: 11/21/09
10:11 AM

Guys, let me help you out,  the 3/4 problem you refer to is almost always due to line pressure.  Its a repeat failure caused by not addressing the root problems.  99.9 percent of the time it is NOT an electical problem,  can it be,  yes  but I do about 300 of these a year, and have only seen a cpl that are.

After the rebuild,  assuming your air checks and that are all correct, and clearances are good,  you need a baseline EPC/line pressure.   You need to check for a cpl things,  first  is base being high enough,  then propper rise from a functioning EPC.. and yes they almost always check good,  but mechanicly may not function.  Then you need to check for constant good pressure in 4th gear....


Normaly the culprit for low line pressure is the AFL valve,  and also sometimes the boost valve in the pump.   Probably the biggiset problem on rebuilds is leaving the filter out of the pump...  it will bite you everytime..  and very quickly.   There are really no gasket issue,  although 2000 and up are a bit different,  they will work,  (although it tears the gasket a little)
Feel free to email me at  gm_charlieatverizon.net  if you have a specific question......  

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