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Username Post: 97 Suburban Shifting Problems        (Topic#199853)
KUTOYZ 
Forum Newbie
Posts: 5

Reg: 05-05-07
09-29-08 11:51 AM - Post#1531663    

Hello. I'm new to this forum. I did a search for my problem but could not find anything, so I hope someone can help me. I have a 97 Suburban, 4WD. The truck has 60K miles on it. The truck shifts extremely hard (hear a loud clunk)from first to second gear, the rest of the shifting is ok. This only happens on longer trips while driving on the highway and starts to happen when I stop and go again, otherwise the tranny is fine. The dealer said it was the torque converter so I paid the $1500 to have it fixed. But that didn't work and now I have to deal with them. The truck returns to normal shifting one it has cooled down and rested for a few minutes. Any ideas? Sorry if I can respond right away. Thanks for any help or any suggestions.



Edited by KUTOYZ on 09-29-08 11:55 AM. Reason for edit: No reason given.

 
someotherguy 
Senior Moderator
Posts: 29303
someotherguy
Loc: Texas
Reg: 08-01-03
09-29-08 12:17 PM - Post#1531682    
    In response to KUTOYZ

Welcome to the forum,

I was going to suggest you check our FAQ post but our current one is missing at the moment!

This is an extremely common issue with these transmissions; I'm surprised the dealer is trying to mislead you by claiming it's the torque converter. I'm even more surprised they're trying to charge you $1500! for replacing something that isn't the problem, anyway.

You may or may not be noticing that you're also getting the Check Engine Light when this problem starts happening. You should have a P1870 error code stored, which is telling you the transmission is slipping. Reason for it is there's a bore inside the valve body that gets worn out; repair involves either replacing the valve body, or using a kit to ream the bore out to sleeve it. Either is acceptable and honestly the kit seems more like a long-term fix to me.

Any HONEST transmission shop will only charge you a few hundred bucks at most for this.

The problem isn't correcting because the transmission cools off; the code is cleared out when you're turning off the engine, and it takes a little while for it to set again. This is consistent with the behavior for the P1870 code. In a nutshell what is happening is the computer detects the transmission slipping a little due to loss of pressure from the internal leak, and boosts the line pressure in an event to save the transmission. This results in the harsh 1-2 shift. The other shifts are firmer too but they're softer by design than 1-2 so you don't notice it nearly as much, if at all.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
KUTOYZ 
Forum Newbie
Posts: 5

Reg: 05-05-07
09-29-08 02:15 PM - Post#1531784    
    In response to someotherguy

Richard-

Thank you so much for the information. You are correct that I did get the "check engine" light, but they did not tell me what the code was. I took it in because the manual said it was an emissions problem and didn't think it would cost me that much, but the dealer was convinced the torque converter would solve the shifting problem. I live in the Los Angeles area...any suggestions where I can take it to get fixed? Can the dealer do it if they offer to credit me for some of the torque converter? Again, thanks alot for the info.

-Kevin



 
someotherguy 
Senior Moderator
Posts: 29303
someotherguy
Loc: Texas
Reg: 08-01-03
09-29-08 02:32 PM - Post#1531799    
    In response to KUTOYZ

Oohhh, ouch. I'm sorry; I mis-read your post and thought the dealer had quoted you the $1500 and you hadn't gone through with it yet. I hate to be the guy to tell you that they stung you for that; $1500 is about the going rate for a full transmission rebuild at a quality independent shop around where I live (Houston TX.)

You might have an uphill battle on your hands with that dealer but if you want to fight with them, the P1870 code should have been CAKE for them to diagnose and repair; they sold you grossly unecessary and overpriced service. I personally would never, ever do business with that dealer again in any way, shape, or form; their failure to properly diagnose it also would have me leery of them doing any work to the truck whatsoever even if it were FREE!

If you must go the route of working with that dealer, it's a simple task for them to simply replace the valve body. That's generally the dealership method for handling the P1870 code. An independent shop is more likely to be set up to install the sleeve kit; the kit and the special reamer are sold separately and the reamer is a little expensive for the DIY mechanic - so it's more likely an indie shop would have this stuff on hand. As far as locating a shop you can trust, that would have to come from word-of-mouth from your friends, co-workers, etc. but going in there armed with the knowledge of what a P1870 code actually is, knowing the actual source of the problem, you're ahead of the game.

In fact, here's a GM technical service bulletin (TSB) about the issue:

------------------------- -------------------

CODE P1870 / CODE 1870 Service Bulletin from GM:

---------------------

TSB # 01-07-30-023A
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, 1999 (Julian Date 9015)
This bulletin is being revised to update the Parts Information.

Please discard Corporate Bulletin Number 01-07-30-023 (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. These valves are used in all transmissions produced after January 15, 1999 (Julian Date 9015), 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.

---------------------

* While GM's recommendation is to replace the valve body, do note that there is a kit available to sleeve the valve body instead and this is a completely acceptable means of repair. Any good transmission shop should be able to do this job.

Kevin, I'm sorry you already paid out the bucks to that shady dealer; I wish you'd found us first. At least now you've got the info to get this fixed correctly.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
CDAUSA 
Needs to Get Out More Member
Posts: 12906
CDAUSA
Loc: Texas Panhandle
Reg: 12-31-01
09-29-08 04:13 PM - Post#1531871    
    In response to KUTOYZ

Kevin, Richard's not pullin your leg, just in case you need someone else to tell you.



 
JeremyB 
Senior Member
Posts: 758

Reg: 10-31-01
09-30-08 06:06 AM - Post#1532211    
    In response to CDAUSA

So, in California you have to pay for repairs that don't fix the problem? And $1500 on top of it. I would be back in that shop screaming and probably call a lawyer- actually I would have paid that kind of bill on a credit card and would be calling the credit card company to do a charge back.

To have someone put a kit in the valve body is probably the cheapest fix and possibly the best way to fix.

I am sure Sonnax makes a kit to repair this



 
KUTOYZ 
Forum Newbie
Posts: 5

Reg: 05-05-07
09-30-08 07:09 AM - Post#1532238    
    In response to JeremyB

Thanks to all for your help and information. Like Richard said, I wish I found you guys first. At least I am more informed now to deal with the dealer. Thanks again.

-Kevin



 
someotherguy 
Senior Moderator
Posts: 29303
someotherguy
Loc: Texas
Reg: 08-01-03
09-30-08 10:09 AM - Post#1532336    
    In response to KUTOYZ

Good luck with the dealer. And stick around...we know a bunch of stuff and what we don't know yet, we're burning our eyeballs to raisins trying to learn.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
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