4L60E no shift 1-2

[rpk99]

Hi Guys,
Hope someone can help. My son got a good deal on a 96 blazer(or so we thought). This thing will not shift from first to second unless you let off the throttle. Stupid me thinkin this would be an easy fix. It has 120k, fluid is right color, not burnt, not under full, not over full. Dropped the pan last nite to change shift solenoids and filter. Same thing. After I let off throttle it will shift right and down shift right. Slips bad when kicked down into passing and throws the 1870 code into the computer. And around town it will shift into O/D but my son says it won't shift into O/D on the highway, he says the RPMs are too high for it to be in O/D. I've gotten alot of possibilities from reading other threads, but any help would be greatly appreciated.
Thanx

[Blue Bowtie]

Possibilities are the band, 2-4 servoes, internal oil leakage preventing the band from applying, hub slippage at the reaction sun shell, or valving issues.

If reverse is solid, that rules out the sun shell and hub. If 1st is solid, it all but rules out the direct (forward) clutch, and if 3rd is solid, it nearly rules out the 3-4 clutch stack.

This, of course, presumes that the PCM is attempting to operate the shift solenoids. If the TPS is failing, the VSS is failing, or other inputs are missing, the transmission may operate irregularly.

[rpk99]

Thank you for the help. Yes first ,third and reverse are all solid. I'll check the TPS in the morning. I did not know the VSS was involved with the shift. I thought it was just a sender for the speedo but I will also check that and let you know how I make out. Thanks again.

[herkyhawki]

Does it stay stuck in first or does it "neutral out", or go to neutral between 1 & 2.
I had one that did this on cold mornings. Trans shop removed trans. valve body and cleaned silt form it. changed no parts. Worked fine ever since.

[MT-2500]

Originally Posted by rpk99

Hi Guys,
Hope someone can help. My son got a good deal on a 96 blazer(or so we thought). This thing will not shift from first to second unless you let off the throttle. Stupid me thinkin this would be an easy fix. It has 120k, fluid is right color, not burnt, not under full, not over full. Dropped the pan last nite to change shift solenoids and filter. Same thing. After I let off throttle it will shift right and down shift right. Slips bad when kicked down into passing and throws the 1870 code into the computer. And around town it will shift into O/D but my son says it won't shift into O/D on the highway, he says the RPMs are too high for it to be in O/D. I've gotten alot of possibilities from reading other threads, but any help would be greatly appreciated.
Thanx

It need to be put on a transmission capable scanner and checked out for where the slipage is.

But

A 96 with that code may be caused by a computer internal ground not working.

GM TSB NO. TRANSMISSION SECTION 66-71-03A
Covers the problem.

The updated wiring part no is 12167310.
What no is on your PCM/VCM
When was the manf. built date on door sticker?
If not 16244210 PCM/VCM you may need wiring kit. to fix the problem.
MT

[Mark1950]

I'm not sure if this will help but I received the 1870 code on my 99 sonoma with the same tranny a few years ago - I found this quote from a retired tranny guy

"This is a VERY common problem with the GM 4L60-E transmission. This is 9 times out 10 a VALVE BODY PROBLEM not a transmission problem. You need to pull the TCC regulator valve from the valve body & install a sonnax TCC regulator valve kit. DO NOT LET SOMEONE SELL YOU A TRANSMISSION UNTIL THIS UPDATE IS DONE FIRST!!!!!! This will more than likely take care of your problem. Also the reason you get a hard 1-2 shift is when the P1870 code sets the computer commands max line pressure. I have had a transmission shop for over 20 years & have only seen maybe 1 or 2 times the valve body update not take care of this problem.
Hope this helps you all out."

I had the valve body rebuilt and have had zero problems with the tranny since. The sonnax part is a hardened aluminum replacement. The part runs about 80 bucks and it needs a special tool to ream out the valve body so that the oversize valve will fit. I had a shop do all the work for less than 400 - this included a fluid and filter change.

[MT-2500]

Originally Posted by Mark1950

I'm not sure if this will help but I received the 1870 code on my 99 sonoma with the same tranny a few years ago - I found this quote from a retired tranny guy

"This is a VERY common problem with the GM 4L60-E transmission. This is 9 times out 10 a VALVE BODY PROBLEM not a transmission problem. You need to pull the TCC regulator valve from the valve body & install a sonnax TCC regulator valve kit. DO NOT LET SOMEONE SELL YOU A TRANSMISSION UNTIL THIS UPDATE IS DONE FIRST!!!!!! This will more than likely take care of your problem. Also the reason you get a hard 1-2 shift is when the P1870 code sets the computer commands max line pressure. I have had a transmission shop for over 20 years & have only seen maybe 1 or 2 times the valve body update not take care of this problem.
Hope this helps you all out."

I had the valve body rebuilt and have had zero problems with the tranny since. The sonnax part is a hardened aluminum replacement. The part runs about 80 bucks and it needs a special tool to ream out the valve body so that the oversize valve will fit. I had a shop do all the work for less than 400 - this included a fluid and filter change.

The shift kit and valve body deal is only a band aid on the real problem of code 1870.
MT

[blazes9395]

Originally Posted by Mark1950

"This is a VERY common problem with the GM 4L60-E transmission. This is 9 times out 10 a VALVE BODY PROBLEM not a transmission problem. You need to pull the TCC regulator valve from the valve body & install a sonnax TCC regulator valve kit. DO NOT LET SOMEONE SELL YOU A TRANSMISSION UNTIL THIS UPDATE IS DONE FIRST!!!!!! This will more than likely take care of your problem. Also the reason you get a hard 1-2 shift is when the P1870 code sets the computer commands max line pressure. I have had a transmission shop for over 20 years & have only seen maybe 1 or 2 times the valve body update not take care of this problem.
Hope this helps you all out."

.

The sonnax update does correct the problem many times. Its a known problem with these trannies. Usually if everything else checks out with a tranny scanner(all readings look alright), getting the valve body reamed out and installing a new valve will correct bore leakage and restore hydraulic integrity to the tranny.

It is a tough call by garages because if it doesn't correct the problem, you'll have an angry customer come back demanding answers etc, etc. Thats usually the reason why shops just want to pull it and take it apart. In my opinion, if the scanner shows good operation within the tranny, I wouldn't hesitate to just update the valve body, update the valve body plate. Sonnax, TransGO, and Superior makes kits to update these valve body. I have used all and have found the TransGo and especially Sonnax work great.

[MT-2500]

Info - Component Slipping/DTC P1870 - Diagnosis #99-07-30-005 - (03/18/1999)Table 1: TCC System Symptom Table Table 2: Internal Transmission Symptom Table Component Slipping/DTC P1870 - Diagnosis1996 Buick Roadmaster 1996 Cadillac Fleetwood 1999 Cadillac Escalade 1996-99 Chevrolet Camaro, Corvette 1996-99 Pontiac Firebird 1996-99 Chevrolet and GMC C/K, M/L, S/T, G Models 1996-99 Oldsmobile Bravada 1996-99 Holden Commodore with Hydra-matic 4L60-E (RPO M30) DescriptionMany technicians experience difficulty when diagnosing 1996-1999 4L60-E transmissions with a DTC P1870 (Transmission Component Slipping). The purpose of this bulletin is to provide assistance for technicians that have already completed the DTC P1870 diagnostic table in the Service Manual. This bulletin will provide a diagnostic strategy for solving DTC P1870 concerns as well as give some of the most common causes for a DTC P1870. General Information ImportantChevrolet Camaro, Pontiac Firebird with 3.8L V6 Engine experiencing a slip condition at 70-90 km/h (45-55 mph) when the TCC applies should refer to Corporate Service Bulletin 77-71-70A for calibration re-flash. 1996 Chevrolet and GMC C/K, M/L, S/T, G Models, and 1996 Oldsmobile Bravada with VCM and 4L60-E (RPO M30) with a slip or flare on the 1-2 and/or 2-3 upshift, or no 3rd or 4th gear, or launch shudder should refer to Corporate Service Bulletin 66-71-03A to ensure that a poor internal ground in the VCM does not exist. A DTC P1870 indicates that a mechanical malfunction exists. If any other DTC's set along with a DTC P1870, then diagnose those first. A DTC P1860 (TCC PWM Solenoid Circuit Electrical) will set if a TCC PWM solenoid circuit failure exists. A DTC P0740 (TCC Enable Solenoid Circuit Electrical) will set if a TCC enable solenoid circuit failure exists. When attempting to duplicate DTC P1870, it is critical that a normal operating temperature of 82°C (180°F) to 93°C (200°F) be reached. It may be difficult to attain the transmission temperature required to adequately cause the DTC to duplicate. Allow the vehicle to idle to assist in warming the powertrain. Optimum speed to duplicate the DTC P1870 is between 89 km/h (55 mph) and 107 km/h (63 mph). Commanding the TCC ON and OFF several times with the Tech II is critical to monitoring slip when sticky valves in the valve body are suspect. If the customer brought in the vehicle for a temporary harsh 1-2 shift and no driveability concerns are seen during a test drive, then remember that a harsh 1-2 is a result of the PCM commanding maximum line pressure from recognizing a DTC P1870. The PCM must recognize that a DTC P1870 has set in two consecutive key cycles to illuminate the MIL. If a DTC P1870 is not recognized on a second key cycle, then normal line pressure returns. Vehicles should be inspected for correct tire size, axle ratio, or calibration. Diagnostic ApproachActionYesNoAttempt to duplicate DTC P1870. Did you duplicate DTC P1870?Go to Slip Check ProcedureGo to TCC System Symptom TableSlip Check ProcedureThis procedure will assist in isolating what area of the transmission is causing your slip, either the TCC system or internal transmission components. After you have isolated the origin of the slip, then utilize the TCC System Symptom Table or the Internal Transmission Symptom Table of this bulletin for most common concerns. To check for a TCC system concernTCC slip can occur either hot or cold or in both conditions. First, perform the following test at cold transmission temperatures, then perform the same test at normal operating temperature. Ideal slip from the transmission with the TCC applied is 50 RPM or less under light to normal throttle, no heavy engine load or hard accelerating conditions. Use the Tech II scan tool to monitor TCC slip while driving the vehicle in 4th gear at steady speed with the TCC commanded ON. When the TCC is applied or released (release the TCC with brake pedal, not the scan tool - release the TCC by lightly applying the brake pedal while simultaneously maintaining a steady throttle position), the slip speed should drop or rise 150-300 RPM. If the slip speed does not drop, then the DTC P1870 is being caused by the torque converter system. ActionYesNoDid TCC slip speed drop (150-300)?Continue Slip Check Procedure for an internal trans concernGo to TCC System Symptom TableTo check for an internal transmission concernSlip should be checked in every gear to isolate in which gear the slip may be occurring. Drive the vehicle in each forward gear range D1, D2, D3 and D4. Command the TCC ON with the Tech II in each gear and monitor slip speed. ImportantVehicle speed must be over 11 km/h (7 mph). Some TCC slip is normal when the TCC applies directly after 11 km/h (7 mph) is reached. If the slip speed remains constant from gear to gear, then the condition is most likely TCC related. Example: Slip speed is higher in second and fourth gear than in third gear. This would lead a technician to a possible slipping band. ActionYesNoIs slip speed equal in all gears?Go to TCC System Symptom TableGo to Internal Transmission Symptom TableImportantThese symptom tables are to be used when the following symptoms are associated with a DTC P1870. TCC System Symptom Table SymptomCausesTCC SLIP (100 RPM SLIP)Check for bronze bushing material in the pan and filter. If bronze material is present, then the stator bushings (234) and turbine shaft (241) should be replaced (Bronze bushing may turn black with an acrid odor). The turbine shaft and housing (621) should be replaced if damaged. In rare instances, it may be necessary to check for an overheated torque converter (24) (Blue and/or distorted converter). TCC solenoid (66) - Perform leak check. Converter clutch valve (224) in pump should be checked for 13 mm (0.500 in) of bore travel without binding. Turbine shaft O-ring seal (618) cut. Turbine shaft hole not drilled to full depth. This concern can be checked by squirting trans fluid through the turbine shaft hole to check for full flow. This is a low mileage failure. NO TCC APPLY (300 RPM SLIP)Converter clutch valve (224) stuck closed (Check for debris in valve bore). TCC PWM solenoid (396) broken/cracked. Visually inspect solenoid. TCC solenoid (66). Perform leak test. Turbine shaft O-ring seal (618) omitted. TCC SLIP WITH STALL STUMBLEConverter clutch valve (224) stuck open (TCC is applying).INTERMITTENT TCC, OK COLD, SLIPS HOTTCC PWM solenoid (396). Leak test solenoid. The TCC regulator apply valve (380) and/or converter clutch shift valve (224) may be sticking/side-loading. It is possible there will not be any damage to the valve upon inspection. Transmissions produced after 2/1/98 will have a groove cut into the spring end of the regulator apply valve. This design is to help float the valve in its bore (replace valve body assembly). Internal Transmission Symptom Table SymptomCauses3RD OR 4TH GEAR SLIP3-2 downshift solenoid (394) ball seat retention failed. Leak test solenoid. Usually associated with a 3-4 clutch/band worn. 3rd accumulator retainer and ball assembly (40) leaks. Test for proper check ball operation. Usually associated with burned 3-4 clutch. NO 4TH OR SLIPPING 4TH Check ball in the wrong location or extra check ball that has dropped behind the spacer plate during trans assembly. The extra check ball can block the 4th apply servo feed. Clutch orifice cup plug (238) not fully pressed in. SLIP/FLARE IN ANY GEARPump slide inner spring (207) or outer spring (206) omitted causing a slow slide response.NO 3RDClutch orifice cup plug (238) blown out.HARSH 1-2 UPSHIFT4-3 sequence valve (383) stuck in bore by sediment.NO 2-3 UPSHIFT2-3 shift valve (368) or 2-3 shuttle valve (369) stuck in bore by sediment.NO 3-4 UPSHIFT3-4 shift valve (385) stuck in bore by sediment.Service InformationRefer to the appropriate Service Manual for replacement procedures. Warranty InformationLabor Code: Refer to Labor Time Guide for correct labor operation. Please use the closest available labor operation for the diagnosis performed. GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION© Copyright General Motors Corporation. All Rights Reserved. --------------------------------------------------------------------------------.

[MT-2500]

Out side of some TPS sensors and pressure sensors and pcm problems.
The root problem of the 1870 code is inernal problems.
Which is the cause of valve body wear on older ones. around 96 - 99.
From 2000 up the transmission valve bodys have already been updated with the hard valve body bores and valves.
Here is what a export transmission mans has to say about the valve body kits.

Quote from Transman Bat auto transmissions.
In a nutshell, the valve body does chronically wear in the 4L60E especially in the lockup PWM bore. The code lights when there is more then 100 rpm or so when locked up. Depending on mileage and fluid condition will determine the next course of action. The seal on the input shaft gets tons of heat and is the most critical seal in the trans. If there are high miles, usually what it takes to wear the vb, then the rubber seals as well as the Teflon ones are just as worn. The 1870 code is telling me there is a internal leak in this trans...someplace. The transmission is a multitude of leaks and it is engineered that way, some are good leaks because they lube planetaries and some are not so good because they make the pump work harder to make up for the leaks inside. Teflon rings leak to get enough holding power to not leak. The point here is if you have excessive or extra leaks then the PWM must cycle higher pressure and volumes to compensate making it work harder and the very forces that wear out the vb bore are increased wearing the bore quicker. In addition to that factor, with internal leaks you also have increased temperature and heat kills big time in a tranny plus it decays the additives in the fluid itself and now you are in a downhill spiral as the trans self destructs form leaks and heat and destruction of the fluid itself. Now the hard parts will start to wear at an increased speed, the pump is trying to maintain for the fluid loss(leaks), the planets will start overheating as the bushings wear out you generate more hemorrhaging and more damage.
Yes, at that point the vb is a bandaid, it may solve the problem for now but the internal wear and hardening of the seals is still there and will continue to wear. The problem I have with just throwing a vb at this problem is simply, the worn components will make the new vb work harder and cycle more than it should and the consequence of that is another prematurely worn out vb and ultimately overhaul of the trans that you should have taken care of before. The transmission is a complete and interdependent unit meaning all parts rely and interact on each other. If one part is worn out then you must deal with the unit on the whole. There are exceptions to every rule and the jeep is a good one, the accumulator plate is held down by too few screws and the plate is under enough pressure that when the screws break, the plate peels back like a lid on a dog food can. If caught soon enough then a repair of the valve body is sufficient to be a complete repair. If you have a 4L60E with 100k on it and smokey fluid and only a P1870 then you are not doing the customer a service by simply replacing the vb.
I have yet to take a trans apart that was simply coding 1870 and not found hard seals or other problems internally. Most of the time, I have not even needed to deal with the vb at all, aside from basic clean up and solenoid replacements. I have had to replace more transfer plates than valve bodies from the balls eating through. In the past 6 months, I have replace 2 valve bodies. I do not use the sonnex kit although the place I get my vb's from does.
I hope this helped you understand why I claim the 1870 code means internal problems more than just throwing a vb in my experience.
BY Transman