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2000 S10 Ext. Cab LS, 4.3L, RWD
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Discussion Starter #1 (Edited)
I recently rebuilt the 4l60e on my 2000 S10 4.3L 2WD.
It was slipping out of 4th while in D so I drove it for a week in 3. Eventually, 3rd gear was slipping, especially when warmed up, so i decided to rebuild.

I got a vacuum tested reman valve body from Shift Rite Transmission shop with the Sonnax TCC Isolator Sleeve installed. It included all new solenoids. I also got a reman pump (old pump was scored up inside) from same shop with upgraded Sonnax boost valve. I installed pinless accumulators and new Transgo seperator plate with new gaskets and new checkballs. I upgraded to Sonnax smart shell and installed Sonnax Heavy Duty 3-4 backing plate with appropriate steels and frictions. All new steels and all new HE frictions - All clearances (including input shaft endplay) within spec checked 3+ times. New Borg Warner Dual Input Sprag. New reverse input drum. New 2-4 band. New 3rd accumulator checkball capsule tested for leaks. Sonnax Servo Release Check Valve installed over it. Standard Toledo rebuild kit for seals and gaskets, etc.. Also, new VSS and new Neutral Safety Switch. All new bushings. 400 grit emery cloth sanded journals on everything. Cleaned MAF sensor with cleaner.

I diagnosed a leaking input drum housing at the shaft and got a new one with new blue rubber pistons. Old 3-4 clutch pack was in decent shape from before but still replaced new. Air-tested new input drum cold and it did not leak where the shaft and housing meet. The plate stiffener was loose during disassembly so after rebuild delayed thud into Reverse was fixed.

When I bought the truck about 500 miles before the 3-4 went out the CLUSTR fuse was blown causing limp mode. After replacing the fuse truck drove fine until 3-4 problem. This leads me to believe that there is maybe some electrical issue, but no code was thrown until the slipping got terrible. It was solenoid B electrical (P0758), which I replaced and code disappeared. It came on again a few drives later and then disappeared the drive after that no changes on my part.

During test drive after rebuild it was SO damn nice and smooth at first I couldn't believe it. THEN after it warmed up all of the 3-4 slipping returned and I had to drive it home in 2nd.
I disconnected the MAF sensor and drove it until warm to rule that out. No luck there. Slightly firmer shifts, but did not help slipping.

I'm thinking now that possible causes could be:
  1. New solenoids - one may be bad,
  2. The input drum doesn't leak when cold, but does when hot,
  3. The 3rd accumulator check ball is bad when hot (I wasn't too sure of my vacuum test being accurate, which said it didn't leak, so I tested with 50/50 solvent and ATF and it did not leak while cold),
  4. or there is a bad wire somewhere considering the original P0758 code that came on and off 2 times.

ANY insight or ideas would are very appreciated. I've spent countless hours on this and is my 1st rebuild.
 

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Discussion Starter #2
Just realized I should've posted this in other category. Please, any moderators could move it over that'd be great. Thanks.
 

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Been there Done it
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ANY insight or ideas would are very appreciated. I've spent countless hours on this and is my 1st rebuild.
About the only insight I can provide is that the majority of 1st time transmission rebuilds end up coming back out for something that was missed.
Hopefully @Tranzman our resident 4L60E Guru will pop in with some suggestions.
I'm sure he'll ask how many and which (including the thickness) clutches and steels you used in the 3/4 clutch pack and what clearance you set them at.
I also seem to remember reading an article on Sonnax's website about various pressure leak points in the 3/4 apply circuit.
 

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Discussion Starter #4
About the only insight I can provide is that the majority of 1st time transmission rebuilds end up coming back out for something that was missed.
Hopefully @Tranzman our resident 4L60E Guru will pop in with some suggestions.
I'm sure he'll ask how many and which (including the thickness) clutches and steels you used in the 3/4 clutch pack and what clearance you set them at.
I also seem to remember reading an article on Sonnax's website about various pressure leak points in the 3/4 apply circuit.
Thanks man. Yeah I've read that article ("All Over the Map...") and used it to diagnose my original problem (leaking input drum). The only thing I haven't been able to go into was the electrical side of things due to lack of a sufficient transmission scanner.

I used Sonnax Heavy Duty 3-4 Clutch Backing Plate Kit - Part No. 74140-01K with seven .067" frictions and six .095" steels. My clearance was .062 which is slightly above spec in instructions. I called and spoke to their techs and they said this would be perfectly fine. The tech said this range should really be .050 - .070.
 

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Mr Goodwrench's Evil Twin
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Go to youtube and search for "precision transmissions". They have a bunch of 4l60e teardown videos and the guy is VERY knowledgeable. He tells all the things to check for, what you can do inside there to prevent certain issues from happening again, mistakes people commonly make rebuilding them and simple upgrades you can make for better shifts and durability. Maybe something there would be of use to you.
 
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Randy
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Sorry for no replies before, I have been overly swamped lately. 3 bench jobs a week since July.

This sounds like a pressure problem. Have you put a gauge on it yet? pressures while driving should be about 120-180 PSI. 70-90 PSI @ idle, 220 PSI @ full throttle. Reverse should give 120PSI @ Idle, 250+ PSI @ WOT.
I try to make my 3-4 clutch clearance around the .030-.050 range you can add a .106 steel or 2 to get it on the tight side of things.
I also heat up my input drums to about 220 degrees (over a kerosene heater in the cooler months, set them in the direct sunlight in the summer) and test them hot. if I just take them from the hot wash @ 170 degrees I have seen the drum still seals. The motor and trans fully warmed runs about 195-200 degrees, that makes 170 a bit on the cool side.
 
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Been there Done it
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Randy,
Did you get my PM from last week?
 

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Discussion Starter #8
Sorry for no replies before, I have been overly swamped lately. 3 bench jobs a week since July.

This sounds like a pressure problem. Have you put a gauge on it yet? pressures while driving should be about 120-180 PSI. 70-90 PSI @ idle, 220 PSI @ full throttle. Reverse should give 120PSI @ Idle, 250+ PSI @ WOT.
I try to make my 3-4 clutch clearance around the .030-.050 range you can add a .106 steel or 2 to get it on the tight side of things.
I also heat up my input drums to about 220 degrees (over a kerosene heater in the cooler months, set them in the direct sunlight in the summer) and test them hot. if I just take them from the hot wash @ 170 degrees I have seen the drum still seals. The motor and trans fully warmed runs about 195-200 degrees, that makes 170 a bit on the cool side.
Hi Randy,

Thanks for your response and information as well as how you heat the drum to test. If I end up having to get into it again I will definitely heat the drum. Glad you have work and enough of it to be busy.

I have not hooked it up to a pressure tester yet.
I am doing the ATSG pay per call currently. The technician recommended a corvette servo and pin with seals.

I installed a TransGo Corvette servo and a Sonnax pin (with 3 seals) ground down to allow 1/16 to 1/8 movement. Band does not drag. After idling about 10 min to warmup the engine and trans a bit, I test drove today for about 4 miles, up a prolonged hill for about 1 mile and down it on the way back. It did not slip at all and the 1-2 shift was much improved. 2-3 felt the same but didn't go to neutral this time. Down shift from OD to 3rd was better as well as coming off of lockup. Lockup came on without a hitch. I cannot do a full road test with it just yet as I changed my oil cooler lines and now have a leak at the radiator at the upper fitting. I suspect a bad o-ring there. If not then I may have cracked the plastic and will need a new radiator.

Will update further when I fix the leak and have a proper test drive.

If it were you Randy, how would you test drive and on what grade(s) to test the 3-4?

Also, if you know off hand, I have much larger than stock tires and know that my odometer is a little off as a result of this. I have a programmer to update the tire size in the ECM. Will this help in anyway with my transmission performance?


Thanks,
Brad
 

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Discussion Starter #9
Go to youtube and search for "precision transmissions". They have a bunch of 4l60e teardown videos and the guy is VERY knowledgeable. He tells all the things to check for, what you can do inside there to prevent certain issues from happening again, mistakes people commonly make rebuilding them and simple upgrades you can make for better shifts and durability. Maybe something there would be of use to you.
Thanks for the response and info on that channel. I'll check them out!
 

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Randy
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If it were you Randy, how would you test drive and on what grade(s) to test the 3-4?
Just a normal road test for shift feel and firmness. Shifts should be firm, but not harsh without overlap. I use roads with a slight grade for TCC slip code testing
Also, if you know off hand, I have much larger than stock tires and know that my odometer is a little off as a result of this. I have a programmer to update the tire size in the ECM. Will this help in anyway with my transmission performance?
How much larger tires? what size? Larger tires put a larger load on the 3-4 clutch. I personally hardly ever use the stock 6 friction 3-4 clutch set up. I use the 4L65E stack in most 60E's. Fixing the the tire size in the PCM won't change the overall performance. Shift kit & .500 boost valve will change that.
 

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Discussion Starter #11
UPDATE:
  • So I installed new fittings at the cooler and it solved the leak. Bad o-rings - they were flat and torn.
  • After a proper test drive it still slips, but now only when all the way hot instead of when warm.
  • I bought a pressure test kit and did a pressure test with gauge duct taped to windshield. On the end of my test truck threw a code P0758 so I manual 2nd drove home (~1/2 mile).
Here are the results of pressure test:

At Idle(cold/warm): D-60/60, R-70/70
At stall/high idle-~2kRPM(cold): D-210, R-270
Shift from 1st to 2nd(cold/hot): 110/110
Shift from 2nd to 3rd (cold/hot): 90/90
Shift from 3rd to OD(cold/hot): 70 1st time (maybe I misread) and 90 the other 2 times/90

Pressure seems alright to me??


After contacting ATSG, the technician recommends switching solenoid A and B wire at transmission plug from ECM and the same wires at the ECM harness.
He said this will reveal a bad wire as cause of problem OR that I need a new internal transmission harness or ECM.
 

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Discussion Starter #12
Just a normal road test for shift feel and firmness. Shifts should be firm, but not harsh without overlap. I use roads with a slight grade for TCC slip code testing

How much larger tires? what size? Larger tires put a larger load on the 3-4 clutch. I personally hardly ever use the stock 6 friction 3-4 clutch set up. I use the 4L65E stack in most 60E's. Fixing the the tire size in the PCM won't change the overall performance. Shift kit & .500 boost valve will change that.
Thanks Randy.

I did the road test as you stated.
The tires are 30x9.5R15 LT 104S
It has a .500 boost valve in it already.
The shift kit I will keep in mind.

Check my previous reply for an update with what's going on if it interests you.
 

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Randy
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To me the pressures seem a little low on the driving part, but if you have a light foot on the pedal it would be ok. It's the curve that seems off. Switching grounds for the solenoids at both ends would indeed give a bad wire up. I like it, thinking outside of the box.
If you still get a P0758 after that, I would lean on bad solenoid. With said I have had a bad ECM before not grounding properly.
 

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Discussion Starter #14 (Edited)
To me the pressures seem a little low on the driving part, but if you have a light foot on the pedal it would be ok. It's the curve that seems off. Switching grounds for the solenoids at both ends would indeed give a bad wire up. I like it, thinking outside of the box.
If you still get a P0758 after that, I would lean on bad solenoid. With said I have had a bad ECM before not grounding properly.
I was purposely keeping my foot light as that is when it was most likely to slip. The solenoid is brand new and I had that code twice before I rebuilt. Once before and after replacing the solenoid. 2nd time turned off on its own next time I started the truck.

UPDATE:
So here's the weird thing - after the wire swap, it works perfectly without any slipping. Been doing 20 mile drives to test and see if I can get it to slip on the highway doing 55MPH up and down slight grades.

I'm happy it's working now, but a diagnosis of the exact problem still remains. Unless the connectors or pins had some corrosion on them that came off during the wire swap I can't put my finger on it. I was expecting the same code (P0758: Sol B) or a code for the other solenoid (P0753: Sol A).
 

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Randy
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I have fixed more than one transmission electrical gremlin with a connector clean and new dielectric grease. The one I remember the most is a 1996 K10 truck that had been to 2 other shops. All I did was confirm the trouble codes and start my diagnosis. In the attempt to repair, I started at the PCM looking for the updated ground per a bulletin, checked my connections and they checked out. Decided to clean and apply a small amount of grease to all the PCM connectors. Once the PCM has been disconnected, codes are cleared and I needed to drive to see if the codes would return. My customer stated that the code once cleared would return with KOER. I drove it as if it was my own truck for 3 days and they never did return.
 

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Discussion Starter #16
I have fixed more than one transmission electrical gremlin with a connector clean and new dielectric grease. The one I remember the most is a 1996 K10 truck that had been to 2 other shops. All I did was confirm the trouble codes and start my diagnosis. In the attempt to repair, I started at the PCM looking for the updated ground per a bulletin, checked my connections and they checked out. Decided to clean and apply a small amount of grease to all the PCM connectors. Once the PCM has been disconnected, codes are cleared and I needed to drive to see if the codes would return. My customer stated that the code once cleared would return with KOER. I drove it as if it was my own truck for 3 days and they never did return.
Wow, that's great news to hear that transmission problems were fixed with just a good clean. I'm going to swap the wires back so everything is color coded appropriately again and give things a proper cleaning. What would you recommend I clean it with? I was thinking a good contact cleaner spray out of all the connectors and pins. And where should I apply the dielectric grease - around the edges of the connectors?
 

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Randy
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Wow, that's great news to hear that transmission problems were fixed with just a good clean. I'm going to swap the wires back so everything is color coded appropriately again and give things a proper cleaning. What would you recommend I clean it with? I was thinking a good contact cleaner spray out of all the connectors and pins. And where should I apply the dielectric grease - around the edges of the connectors?
I use CRC lectra-motive. the dielectric grease, I just apply a small amount to the female side of the connector.
 

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Discussion Starter #18
I use CRC lectra-motive. the dielectric grease, I just apply a small amount to the female side of the connector.
Thanks for the info on what you use.

UPDATE: Got a code for the other solenoid (P0753-Solenoid A Electrical) today while driving. Felt like I was having some torque converter lockup issues while going uphill until it slipped about 1k RPM and threw the code. Glad to finally know my problems were a bad wire. Now to change the wire and then I'll report back.
 

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Discussion Starter #19
UPDATE: I switched the wires back to their original configuration and replaced the bad one with a good one from a pick-a-part blazer harness. The transmission ran great for awhile. After a couple hundred miles, I got a code for P0753. Weird, because that wire was the good one (after switching back to original configuration.) I thought it was a bad PCM, but after I checked the connectors at the PCM I realized the pin for solenoid A had been backed out. I pushed it back in all of the way and taped down the tab that had become too pliable, after messing around with switching wires, and wouldn't lock in the pin. Code, slipping, and power loss resolved!! It has been running great for another couple hundred miles since the e-tape fix of the pin lock tab on the connector. I replaced the TPS and my shifts have improved dramatically. When the torque converter would come off and on I would really feel it as well as downshifts into 3rd. Now it is VERY smooth all the way around and I have MUCH better throttle response and power. HIGHLY recommend a Throttle Position Sensor replacement if is old. Only $40 for OEM and a bit of cussing if you decide not to take off the thermostat housing and connected hose like I did. I'm waiting on a MAF sensor that's delayed in the mail due to the cold weather across the US. Today I'll be replacing the 170k mile old O2 sensors. I'll report back on the transmission performance and overall power changes (if any) after I install all of these sensors and drive the truck a bit.
 

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Discussion Starter #20
POTENTIALLY USEFUL INFO FOR SOLENOID A/B ELECTRICAL CIRCUIT PROBLEMS:

This is only MY experience here, but I wanted to share as it may help others looking for solutions.

When I was having problems with SOLENOID B (P0758), 3-4 slipping would occur primarily under LIGHT throttle.
When I was having problems with SOLENOID A (P0753), 3-4 slipping would occur primarily under HEAVY throttle.

In both instances, there was a PARTIAL grounding issue to the solenoids NOT a complete loss of ground. Also, only one solenoid was being affected at a time NOT a combination of the two. Lastly, this grounding issue was always worsened as everything would warm up to operating temps. and not apparent with cold starts.
 
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