Diesel Place banner

1 - 11 of 11 Posts

·
Registered
Joined
·
120 Posts
Discussion Starter #1
Pulling a load with my pickup it wants to "hunt" between what I guess would be 4th and 5th. I've got the regular Edge Juice set on 4 normal and 2 in tow/haul but the tranny will hold me in the lower gear until the engine is spinning faster than 2500 then if I can get going downhill it'll shift up (finally) I suppose into overdrive and go on until it pulls down again and then back to the screaming for awhile. By the way, all this is in tow/haul mode.


I want to know if the overdrive lockout would help me any? What will it do and how do I tell the dealership that I want it installed? Is there any drawbacks? I just THINK the motor would be much more comfortable if I could get rid of overdrive and hold it into 4th


Thanks much for your time and expertise!
 

·
Registered
Joined
·
747 Posts

·
Registered
Joined
·
994 Posts
I just had my early (11/06/02 delivery) 2002 DMAX's ECM/TCM reflashed. If your 2002 was built before Mar, 2002 and you have not had the ECM/TCM updated, try to get that done first at the dealer. You need to complain about driveability issues (which you have). The dealership I took my truck to wanted to charge me $350 to update the software and install the O/D Lockout switch. I told them just update the software (which they did for free under warranty). It made a difference in holding 5th gear on hills. After the software is updated then test drive it. If you still have issues, you could then install the O/D lockout yourself or pay the dealer. Reference the link below where they talk about the O/D lockout switch in a GM Tech article.





Below, I have cut-n-pasted here two previous posts I made with respect to getting the ECM/TCM updated:


*****************************************************


I'll second what TC Dmax says. I have an early '02 truck. Just had ECM and TCM reflashed about a month ago. I was actually surprised at the difference when towing a trailer. It holds 5th gear much better when going up hill. There is no extra engine power, just the tranny trying to stay in 5th gear instead of shifting into 4th so quickly.


They will not just update the ECM/TCM for you. You have to address/complain about some form of driveability issue. Even then, they may be reluctant since as TC Dmax indicates, there is no going back once it is updated.


I would recommend anyone with an '01 and an '02 built before Feb, '02 to have this update performed.


Reference the following link:


http://service.gm.com:8083/gmtechlink/arcv_pdf/7_02_e.pdf


See page 6 for the article. See page 8 for the Under Transmission/TransAxle (02-07-030-020) for the update


***********************************************


I complained about "shift busyness" and "2-1 Downshift Harshness" (which occurs when doing a slight rolling stop on hills). The dealer researched the available info and on the invoice they indicated that they applied bulletin 020730020, which is in the link I supplied above on Page 8.. My truck had never had an update since I purchased it in 11/06/01.


***************************************
 

·
Registered
Joined
·
169 Posts
OC_DMAX, I got my '02 in dec '01. will it cause anything to change in the operation of the truck? flashed vs non flashed? rpm,mpg anything? dont want to mess up what I do have by getting it flashed. Thanx for the input, AkDually61
 

·
Registered
Joined
·
994 Posts
OC_DMAX, I got my '02 in dec '01. will it cause anything to change in the operation of the truck? flashed vs non flashed? rpm,mpg anything? dont want to mess up what I do have by getting it flashed. Thanx for the input, AkDually61


What you mention above was an issue the dealer was concerned with. They first refused to just do the update because they have had bad experiences where the new update created other issues for the customer. There is no going back.


From my perspective, there were no negative side effects from this change on my truck. The truck in stock form has the same power, same rpm range and same mileage. The reflash fixed the two issues that I had with the vehicle. It seems to hold 5th gear longer while pulling a trailer up a hill (not being quite so quick to downshift to 4th, but it will eventually downshift) and when doing a slight rolling stop in the hills around my house, it does not slam from 2nd into 1st when accellerating from the stop. In that respect, the changes work "as advertised". It appears as if these software changes were developed over a year ago, so if there were bugs in them, hopefully they have them worked out. If you want to add the O/D Lockout switch, you will have to get these updates done to your vehicle. The current software in your truck will not recognize the switch when wired to the computer connector. I am certain there a other "little" software things they also cleaned up along the way. I wanted this done before the 3yr/36kmile warranty expires next November.


Hope this helps,


Alan
 

·
Registered
Joined
·
169 Posts
Thanx Alan, guess I'll be takling to the guys at the shop tomorrow. It can't hurt right? do you have or know anyone who has directions for the diy'r? Thanx, AkDually61
 

·
Registered
Joined
·
1,048 Posts
I have an '02 and had the same "hunting" problem while pulling loads too. I took copies of the TSB mentioned about the "Hunting" and the TSB for the Overdrive lock out button to the dealer and told them that I had every intention of keeping my truck for 300,000 miles. I also showed them my extended warranty (GM) contract. My pitch to them was simple "I think for the cost of the switch, that GM should help me protect our investment. I mean, if this truck fails, I have a minor expense compared to the General." They agreed and installed the ODLO for free and did the re-flash at the same time. Then they ask me not to advertise this. Didn't want to get hit with a lot of ODLO installs. I went back to them recently and they told me that GM has since told the dealers, "no more freebies". Oh well. I got mine and I use the devil out of it.


I still think if you have a GM extended warranty, you might be able to make a pretty good case to have them install it at their expense.
 

·
Registered
Joined
·
994 Posts
AkDually61,


If your referring to installing the O/D Lockout switch, reference the link provided above by flhrciblueice. The TSB is at that location. It looks like a pretty simple job. It would probably take a little bit of effort to round up the parts. But if you were not in a hurry it sure beats paying the dealer over $300 to do the job. I plan on doing this mod as my personal time allows. DMAXALLITECH was talking about putting a kit together several months ago, not sure where that stands.


The KEY here is to get the software upgraded in the ECM/TCM on the 2001 and early 2002 trucks (later 2002 trucks should be OK). Then you can do the job yourself if you want too. GM should not balk at upgrading the software for free, as long as you are still covered by the 3yr/36kmile warranty. Otherwise, you may owe them an hour of labor (at least thats what they wrote on my invoice -- 0.4 hr to update ECM and 0.6 to update TCM). One would need to discuss this with your particular dealer.


AlanEdited by: OC_DMAX
 

·
Registered
Joined
·
120 Posts
Discussion Starter #9
I may try talking to my dealer. I just wondered if it was really worth the time and trouble. The software update concerns me a little though . . . man, I don't want them to mess anything up!


Where is the on/off for the lockout installed?
 

·
Registered
Joined
·
1,715 Posts
look in my sig at kennedys site........less than ten dollars at radioshack a some pins to fit the tcm from the dealer $5 and one hour of your time.......under duramax tech tipsEdited by: sdaver
 

·
Registered
Joined
·
1,048 Posts
The Dealer installed the ODLO button just to the left of the passenger side airbag on/off switch. Easy access and comes with an LED to indicate whether it is engaged or not. I like it.
 
1 - 11 of 11 Posts
Top