Transmission Problems - 4L60E

[danielcwebb]

I have been having some problems with the trans in my 1999 Suburban K1500 (4L60E). I've been having the ocasional hard shifts between 1-2 for a couple of months. Yesterday, I noticed some hesitation shifting from 1-2 under full throttle. I'm not sure if I would call it slipping or not. From a stop at full throttle, it would accelerate fine until 4000-5000 rpm and would then sort of hang up and not shift. It didn't feel like the rpm's were climbing without acceleration, just sort of like it lost power. I know I need to replace the fuel pump and filter, so I'm wondering if that's a potential cause. Once I let off the accelerator, it shifted to 2nd. I did this a couple of times, each time with the same result. Today I ran the codes and came up with 1810 (trans fluid pressure valve position switch circuit) and 1870 (trans component slipping). The 1870 didn't surprise me, but the 1810 has me a little worried. I cleared the codes out of the computer, and now it seems to shift like it used to. I've got 100,000 miles on the truck, so I know a trans rebuild is coming soon, but I'm hoping to get a couple more months out of this so I can get the money together. I'm planing to replace the trans fluid and filter tomorrow. Any ideas other ideas or advice?

[2000CAYukon]

The 1870 can usually be fixed by repairing the valve body (which can be done with the tranny in the vehicle).

I don't know much about the 1810 but will take a look later tonight at my factory manuals.

//2000CAYukon

[danielcwebb]

yeah, i was going to do the upgrade on the valve body. but like you said, i don't know anything about the 1810 code. i haven't been able to find anything on this or any other website.

[RexNfx400]

1810 indicates a problem with the pressure manifold switch in the transmission. Basically, this tells the computer if a hydraulic circuit has fluid pressure and the amount of time to fill it.

[Jeremy-WI]

1810 refers to a problem that the PCM cannot determine what gear the shift lever is in, the service manual does state that a false 1810 could be set after adding or changing tranny fluid and some other conditions. The PCM has three wires from the tranny that should tell it if you have the shifter in park, drive, neutral, d1 or d2, and there are two combinations of signals from these wires that are not valid and will cause a P1810, hopefully 2000CAYukon can make a little more sence out of the description in the manual

[maxwedge]

Check this link for 1810, http://service.gm.com/gmspo/mode6/pd...t53T_CK_aT.pdf

[danielcwebb]

Thanks for all the input guys. I dropped the pan today, and was generally happy with what I found. The fluid was very dirty and the filter was almost totally clogged, but there were no big chunks or shavings, and no burned smell. The magnet had a considerable amount of gunk on it, but the particles were so fine that it almost looked like graphite. A new fuel pump, fuel filter, and trans fluid and filter, and the truck is running great. Far better than it ever has since I've owned it. No new codes have set since I cleared them yesterday. When driving at around 30 mph with the trans in second, when I floor it and it downshifts to first, it will actually throw you back into the seat. It accelerates strong all the way to about 5000 rpm with a nice clean shift to second. I can even chirp the tires on take off. I guess I should still plan on doing the upgrade shift kit for the 1870 code. And I guess I'll change the pressure switch just to be safe. But it looks like it may have just been dirty fluid and filter. Do you guys think I am being too optomistic here?

[2000CAYukon]

Originally Posted by danielcwebb

I guess I should still plan on doing the upgrade shift kit for the 1870 code. And I guess I'll change the pressure switch just to be safe. But it looks like it may have just been dirty fluid and filter. Do you guys think I am being too optomistic here?

Drive it and see if the codes come back. Dirty fluid and filter can cause low pressure situations which can trigger 1870 code.

How long has it been since the last filter and fluid change? I try to do mine every 25K miles.

My 90 GMC K1500 just rolled 127K with the original motor and tranny; although, I did finally install a Transgo Kit and Vette Servo in it. Nothing wild, just a little TLC for the tranny.

//2000CAYukon

[danielcwebb]

I have no idea when it was changed last. I owned it for about 40,000 miles and this is the first time I have done it . The dealer I bought it from claimed that it was done prior to my purchase about 3 yrs ago, but juding from the condition of the fluid and filter, I kind of doubt that. It did have a rubber gasket around the pan (I think it came with paper from the factory, correct me if I'm wrong) so I'm guessing it was changed at some point. Maybe not, who knows. but I can tell you I will be chaning it once a year from this point on.

[Shadetree Tuner]

Dont want to step on your post, but wanted an opinion on my tranny problems. On a road trip, 105k 99 suburban. Lost overdrive and had hard 1-2 shifts, then later, 1-2 shifts went normal, but on 2-3 shifts, I lost rpm and things just didnt feel right. 300 miles from home, had to hit a local chevy dealership. They told me the valve body was the culprit. I had to rent a car to finish my vacation and leave my burb behind. They replaced my valve body and everything seems to be fine. I know the 4l60e has its problems, but I have never heard of a valve body issue. Is this common?

[silicon212]

The valve bodies on these are cast aluminun rather than the older, more durable cast iron, and over time these will wear out.

[danielcwebb]

OK, so things were going great for couple of days. Two days ago after driving for about 15 miles on the highway, I started feeling the hard shifts again. Yesterday, the MIL came back on with the 1870 code again. I'm guessing I have to fix something, but what? Should I replace the whole valve body with a new/aftermarket/remanufactured one? Should I add the TransGo plate? Should I install one of the Superior or Sonnax kits? I really didn't want to have reem out the old valve body. What's the easiest way to fix this that won't cost me a ton of money? I just want to make sure I have everything I need before I tear into this.

[2000CAYukon]

Originally Posted by danielcwebb

OK, so things were going great for couple of days. Two days ago after driving for about 15 miles on the highway, I started feeling the hard shifts again. Yesterday, the MIL came back on with the 1870 code again. I'm guessing I have to fix something, but what? Should I replace the whole valve body with a new/aftermarket/remanufactured one? Should I add the TransGo plate? Should I install one of the Superior or Sonnax kits? I really didn't want to have reem out the old valve body. What's the easiest way to fix this that won't cost me a ton of money? I just want to make sure I have everything I need before I tear into this.

If this was my truck, I would install the SK 4L60E kit from Transgo (see http://www.transmissionpartsusa.com/...000035935.htm).

If you have never removed a valve body or servo, it can be a challenging project. I have not installed the SK 4L60E kit; however, I have installed the 4L60E-HD2 reprogramming kit in a muscle car. (see http://www.transmissionpartsusa.com/...-035935hd2.htm)

Here is webpage that describes the install of the HD2 kit: http://www.inegma.net/mb/index.php?showtopic=3039

The SK 4L60E should address most of the 1870 issues. I am also not sure if the SK 4L60E kit requires removing the servo or not; however, upgrading to the vette servo is a common upgrade along with the SK 4L60E kit.

It might make sense to talk to a tranny shop and see which kits they use.

Another good option is get a kit from Pro-built Automatics (see https://www.700r4l60e.com/store/home.php?cat=28). The kits are custom built to your specs and you can also get new accumulator pistions and/or a vette servo).

Good luck.

//2000CAYukon

[RexNfx400]

Originally Posted by danielcwebb

OK, so things were going great for couple of days. Two days ago after driving for about 15 miles on the highway, I started feeling the hard shifts again. Yesterday, the MIL came back on with the 1870 code again. I'm guessing I have to fix something, but what? Should I replace the whole valve body with a new/aftermarket/remanufactured one? Should I add the TransGo plate? Should I install one of the Superior or Sonnax kits? I really didn't want to have reem out the old valve body. What's the easiest way to fix this that won't cost me a ton of money? I just want to make sure I have everything I need before I tear into this.

The Transgo kit will work fine. The TCC regulator bore is probably worn. This is verified with a scanner and a long drive. To make sure the 2/4 band isn't slipping. But 99% of the time, the valebody it is worn out The Transgo kit converts the PWM(pulse width modulated) torque converter clutch system to an on/off type. As per pre-'97 4L60E models. It works good and you'll never know the difference We don't need no stinking TCC logic on a pickup! Escalade? Maybe, yes...

The Sonnax system is good if you plan on making a living repairing valve bodies or would like to retain original TCC slip logic(EEC3). As you have to invest in the reamer kits. Then you would want to ream and replace the AFL valve also.

A serviced valvebody from GM is cool too.

The Transgo seperator plate is only needed if one of the check ball seats are worn oversize, excessively. 50/50 chance on that.

Just one other thought. Just remember, after all the valvebody repair. Some Other reasons for 1870, but not common, are. Worn TCC lining in converter, TCC O-ring on input shaft and TCC valve bore wear in front pump. Very rare occurances on these parts but it does happen.

[danielcwebb]

I've got some additional info, I don't know if it helps or makes a difference, but here it is. The scanner captured freeze frame data as follows: 1870; 61 mph; 2100 (this is estimate as I don't have the tool in front of me and I can't remember exact number); throttle 31%. Does help diagnose the problem?