My 4L60E story... :(

[Z71]

It all started when my "Check Engine" light came on while driving from Las Vegas to Phoenix. I pulled over and checked what I could under the hood, liquid levels, plugs, hoses etc... and I couldnt find anything. I started the truck back up and eventually the light went off.

 

Over the course of a few months the "Check Engine" light would come off and on but eventuallyI just kind of got used to it doing it and didn't think much of it anymore.

 

One day it really started nagging me for some reason, so I got a friend to read the diagnostic code for me with a new toy he just purchased. The code stated that a component was slipping in the tranny (sorry I can't remember what the exact code was).

 

Then my girlfriend started having troubles with her car. Nothing I could do about my truck now since mine was the only working vehicle in the household, and other than the check engine light, it seemed to be working fine..... well then it started. It seemed that if I drove the truck for any length of time and when the tranny got really hot, it would s**t hard between 1st and 2nd gear. The engine would rev higher than normal before it shifted and when it finally did, there was a jolt as the tranny shifted into second. and everytime, once the tranny cooled down, the problem went away.

 

Then one evening while on the freeway onramp, I hear a racheting noise from down underneath the truck. The noise only came while accelerating. I put the truck in neutral and rev'd the engine - no noise. I put the truck in gear and held the brake firmly while applying gas - no noise. I released the brake and once the wheels started to turn, I heard the racheting noise. Well after a tow to my mechanic and a few days later I got the news, the problem is in the transfer case and a $1,600 check would fix the problem.

 

After I got the truck back, everything seemed fine for a few days then my engine light comes on again followed by the hard shifting. d**n, the transfer case was a complete unrelated problem.

 

Once my girlfriend got her car fixed (it had a alot of problems and was in the shop for a few months) I took my truck into a highly recommended transmission specialist. He read the diagnostic codes and gave me the bad news. Components slipping in the tranny.. etc... He explained that they could crack the case and attempt to locate the problem but it usually ends up costing as much as a rebuilt tranny anyways because of the labor involved. Sooo... I now have a $2,400 rebuilt tranny with warranty in my truck and it shifts like it should again and the engine light has been off for days.

 

d**n truck has cost me over $4K just in the drive train this year. The b*tch better run right for a long time.... also just made the last payment on it.... she's 100% mine now (bought it used from a trusted friend).

 

 

97' GMC Z71 K1500 5.7 Liter with NEW 4L60E tranny.

[firecadet613]

My 2-4 band burned up, and I'm just about to take mine out (hopefully tomorrow) and get it fully rebuilt with some higher quality parts and some performance mods done to it. Only costing me $650 but I'm R&R it. Hope your truck runs great for a while man!

 

Joe

[Cop_Dodger]

The transmission would not have needed to be disassembled if the shop had the correct tools and information. The P1870 code is a common code. The majority of the problems with this code are caused by a worn valvebody. This can be serviced with the transmission inside the truck. You simply take a scan tool and look at TCC (torque converter clutch) slip speed while the TCC is engaged. If the slip speed is greater then 25rpm then the PCM (computer) sets a P1870 (component slip) code and the transmission to maximum linepressure. The maximum line pressure is set to get rid of the slip. This results in the extremely harsh 1st to 2nd shift. There is a bulletin they any competent shop that cars should have access to. I advise you to bring your truck to another shop for now on.

 

_________________________________________________________

 

 

Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body) #01-07-30-023B - (03/22/2002)

Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body)

1996 Buick Roadmaster

 

1996 Cadillac Fleetwood

 

1999-2000 Cadillac Escalade

 

1996-2000 Chevrolet Camaro, Corvette

 

1996-2000 Pontiac Firebird

 

1996-2000 Chevrolet and GMC Light Duty Truck Models

 

1996-2000 Oldsmobile Bravada

 

with 4L60-E Automatic Transmission (RPO M30)

 

Built Prior to January 15, 2000 (Julian Date 0015)

 

This bulletin is being revised to update VIN Breakpoint Date information and revise the Parts Information table. Please discard Corporate Bulletin Number 01-07-30-023A (Section 07 -- Transmission/Transaxle).

 

Condition

Some customers may comment on a harsh 1-2 upshift and the Check Engine Light or Service Engine Soon indicator is illuminated.

 

Diagnosis

 

 

Typically, these vehicles will have been driven more than 32,000 km (20,000 mi) before this condition occurs.

 

The scan tool may show a DTC P1870 set as a history code.

 

A harsh 1-2 shift or DTC P1870, caused by wear in the control valve body, may be difficult to duplicate when the transmission temperature is below 93°C (200°F).

 

Cause

The condition may be due to wear in the control valve body. This wear occurs in the bore that contains the TCC isolator and regulator valves, and results in poor, or no, TCC apply.

 

 

Important

DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.

When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.

This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).

When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.

When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL).

 

Correction

Install a control valve body with the revised TCC regulator and isolator valves. Refer to the Parts Information table below. These valves are used in all transmissions produced after January 15, 2000 (Julian Date 0015), and all of the service parts currently available through GMSPO contain revised TCC regulator and isolator valves.

 

 

Important

If all of the following conditions are true, it is not necessary to rebuild the transmission or to replace additional transmission components beyond the control valve body.

 

Transmission operation is normal before the transmission reaches operating temperature, or before DTC P1870 is set (no slips, flares, or missing gears).

The torque converter is not blue or overheated.

The transmission fluid is not burned or has no burned odor.

The transmission fluid pan contains no abnormal debris (clutch material, bronze, brass, or metal fragments).

[Z71]

Thx for the info. Next time (hopefully there wont be) I will be better educated, but I did drive it for quite awhile this way, I do feel better with a new tranny.... at least that is what I need to tell myself now. LOL

[gould10]

I have 98 w/t with the 4.3 and mine started doing the same thing about 70,000 miles. I took it to dealer ship and they told me that i needed a new transmission for about $1500 or drive it till it dies. So i decided to drive it. Well after discovering this great web site i finally figured out what the problem was. The valve body is shot. Well my truck now has 161,000 miles on it and i never had the problem fixed and it runs fine.