No engine light, old codes P0700 P0741 P0742, transmission seems to shift perfectly smooth, no shuddering??? 2013 Suburban Z71

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

jeffm333

TYF Newbie
Joined
May 25, 2021
Posts
22
Reaction score
38
Location
Tennessee & Nevada mostly
No engine light, old codes P0700 P0741 P0742, transmission seems to shift perfectly smooth, no shuddering… any thoughts? Full details below:

I have been shopping for months for a 2011-2015 z71 suburban or tahoe; preferring the suburban. Finally found one that is a southern-based truck with a good car fax, 130k miles, it was a recent trade no tune up or detailing yet… ran seemingly great, everything I tested operational, engine fired up and idled perfectly smooth, no clunking U joints or engine mounts, transmission shifted smooth, no vibrations, no alignment pulls, interior in above average shape, drove it for about 25 minutes, 4wd engaged without any apparent issue. The dealership was seemingly honest and showed me the mechanics report from where the shop just checked it today - their list included a misfire code that they cleared up by cleaning the plugs up. Said had a pretty good oil drip; rear main seal oil leak. Needed front pads and rotors; brakes were a tad soft but not horrid. Unfortunately also had the P0700 P0741 and P0742 codes - transmission TCM and torque converter related. These are what I am most concerned with and looking for input on. The dealership manager said he was surprised to get the report from the shop as there was no check engine light and seemed to shift and run fine for them when they took the trade; he indicated they were “old codes”. The dealership was willing to work with me to fix all of the list, or leave some unfixed and improve the price for me. He said if I didn’t work something out with them their plan would most likely be to drive the vehicle for 50-100 miles to see if the transmission codes reappear or any evidence of an issue manifests, and they said most likely if they were unsure about it they’d likely choose to just take it to auction and sell it wholesale; so if that was the case they’d also be willing to work out selling it to me instead. They came across fairly sincere and thorough; they certainly didn’t need to tell me about the codes at all as the engine light was off and the vehicle drove seemingly fine.

I’ve been searching the forums and elsewhere for examples of seeing these codes even when the transmission is operating seemingly fine and haven’t found any strong examples. Anyone have any thoughts or input here? I suppose it is possible the previous owner had issues and replaced the torque converter solenoid already, or simply had low or poor ATF they replaced/filled and the issue cleared, and the codes are old/leftover from them. (Albeit this maybe is overly optimistic)

Any thoughts/inputs here? Any suggestions on how to test further or any experience with worst case / best case scenarios?

The only thing I can think of is return Monday and request to start the engine cold, drive it for 100 miles or so, with the transmission temp output displayed on the dash, and monitor for drive-ability issues and then check the codes after the drive. (I ran out of daylight/time today so was not able to check the actual transmission fluid to give it an eyeball-examination, so I will
Do that as well)

Any and all input/help is greatly appreciated.
 

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
19,218
Reaction score
25,361
Location
Treasure Coast, Florida
A Tech-2 is the dealer level scan tool and it can tell you how long it has been since the last codes set and it can view the freeze frame/failure records data. It will also be able to tell you if those codes are current or historical.

These 2 codes can be caused by the pump, the little five cent TCC o-ring, torque converter or valve body and maybe even a speed sensor.

If you really like the car, plan on repairing/rebuilding/replacing the transmission and torque converter and budget accordingly. Ask the dealer to throw in a warranty, my daughter had her 6L80 replaced under warranty, the company had their own supply and shipped it to the dealership along with a new torque converter.

It's possible if these are historical codes that the problem was addressed and they weren't cleared or haven't self-cleared yet. I don't know how that works.

These are great and reliable transmissions when serviced properly under the severe service schedule.
 

petethepug

Michael
Joined
May 4, 2016
Posts
2,530
Reaction score
2,590
Location
SoCal
Work with the dealer to get the trans fixed. You’re not paying for the labor, risk to open the trans or have it replaced. Let them do it all and take the warranty at the end. Odds are the past owner traded it in because of “the old code”.

If you can leave with a new trans and somehow work in the same warranty or service contract on the motor, you’re all set. I’ll betcha weren’t expecting to find that kinda deal.
 

davidavidd

Member
Joined
Oct 29, 2020
Posts
55
Reaction score
74
Location
CO
Proceed with caution: sometimes those codes you mention (P0700 P0741 P0742) don't turn on the check engine light. My transmission died with check engine light OFF, codes found before remove it from my truck: P0741, P0745.
 

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
23,937
Reaction score
35,138
Location
Stockton, Ca.
at 130k I wouldn't 2nd guess the transmission. TC is a well known issue on these trucks but once fixed correctly you will be fine.
a proper rebuild is in the range of $4000-4500. so try and work that in somehow.
 

Dustin Jackson

Full Access Member
Joined
Aug 9, 2018
Posts
1,409
Reaction score
1,559
This is probably the 6L80E right? That's strange, I seem to read more problems with the 6L80E than the good ol 4L60E.
 

Forum statistics

Threads
129,572
Posts
1,818,008
Members
92,807
Latest member
Bobby J
Top