Anybody have this installed on their 01 or 02 truck yet? I have heard that you could go to the dealer and get them to install this feature (for a price).


What did it cost and are you happy with it?

Yes you can get it installed at a dealer, but I think you might find it pricey. I had mine done quite a while ago, but they sent it through as warranty work for "drivability issues." The service manager told me later that they weren't supposed to be able to do that and he had to pull a few strings to get it covered. I haven't used it yet, other than to play around to see it works, but I can see under certain circumstances it will be a nice feature.

Dealer wanted about $350 to do the install. Instead, I bought the 3 pins required, plus a switch and installed it myself for less the $25.


The mod works as advertised. You need to make sure your TCM has the latest software in it. Early 2002 build trucks do not have the correct software. If your truck was built in the April, 2002 timeframe or later, your probably OK.

I installed the factory switch in my truck. Seems like it cost around $50.00. Also had to buy the covers for the cubby hole in the dash where it went and a few pins and other supplies for the install. It works as advertised, but I truly can't see where it has been of much use. I have towed my 5th wheel camper around 30,000 miles and probably haven't used it twice while towing. I think I only used it to keep the truck from speeding up too much going downhill in the rain on slick pavement. Other than that, I have never had any real reason to have it. My truck was built the 3rd week of May, 2002, and it had the correct software to run it already installed, so no problems there.

I bought all the parts ( got a grayhair discount ) at the dealer and installed it myself. The ser. mgr. made a copy of the instructions for installation. Works great and I use it a lot when pulling my 5er in hills.


Jomar

I performed the installation myself using J. Kennedy's instructions and pins from the dealer and a switch and LED from Radio Shack. It is a simple operation. My 02 was built in late May, 02 and did not require reprogramming.


I use it regularly while towing my 12,000# fifth wheel against strong headwinds or in the mountains. I like to tow at 55 to 60mph and it seems the D/A has too much power (not really!) and it wants to go in and out of OD at that low tow speed when under those conditions.


It is also handy going down long hills when towing. It is not as drastic as the tow/haul shifting actions. Actually, the tow/haul mode functions normally. It is just that it can't "see" the hills and sometimes I want to do something different than what it has decided.


I am very happy with the mod and I feel it is much easier on the truck.http://www.dieselplace.com/forum/smileys/smiley1.gif

Mine is installed per the instruction on Kennedy's site. It isn't working yet, but I'm sure that is just programming. I will be making a trip in for some little things and have it programmed then... alone with dropping the idle presets. If you do one, do the other (high idle & O/D lockout) at the same time. All it takes is a couple more wires/pins and you're done with both.

Update: Just got the truck back from the dealer with the new programming. Everything works great. Can't wait to try it on the hills with the camper.

On a side note, I noticed there is less delay engaging when going from N to D. It is about half what it used to be and I like it better. I imagine it has something to do with the updated software.

My '04 LB7 came with the switch. I have used it on one trip out of 15K miles towing 13K-14K. There are certain conditions where you're right on the border and the tranny hunts for a gear. It is nice to just force it to 4th and not worry about cooking it. The one time I used it I was hauling another 1000# (a Quarterhorse) over normal. I think it just depends on your conditions if you'll use it.

Put mine in myself. Took maybe an hour.


Very easy to do, just take your time and do it right.


I complained to my stealer and he said sooooooooo. Then I wrote GM corportate and they said if I wanted to be able to put it in 4th then I ought to buy an 03. Stupid answer.


I would not be without it. I tow 13K 5th and it is essential for towing up and down hills.


Not hard to do.

I also installed the overdrive lockout on my 2002. Did it myself with a pushbutton switch and LED from Radio Shack. Installed the switch and LED in the 4x4 module to the left of the steering wheel, and just above the transfer case push buttons. The components fit easily and the feature is close and handy in this location. After doing the switch and wire installation, took the truck to my favorite dealer, and he installed the software for free and no hassle.

Use this feature all the time when towing!

What is the GM P/N?

I have found a VA 125 box to be a better solution to using od lockout...

My 03 has it and never used it. I substituted more power

Local Dealer put in for me, after i reminded him that I bought the GM extended warranty also. Basically told him that the shift busy-ness and my tow needs might cost GM a whole lot more without the ODLO switch. I love it. Use it to keep the EGTs down and the speed up.

What Is The Purpose Of The Overdrive Lockout? I Tow A 13000# 5er And Have Not Had A Problem Towing.

I use my OD lockout in two situations, all associated with heavy towing:

1. On steep downgrades, I'll lock the transmission out of over-drive early, to help control speed during the descent. Feel I have better control.

2. On steep inclines, I can down shift sooner, to help minimize engine lugging, and to keep the EGT out of the yellow band, i.e. keep the EGT below 1100 degrees. Also, since the Duramax doesn't have infinite power, I'll often downshift into 4th gear when pulling in high head or cross winds, especially across Nebraska on I-80, and up to Denver on I-76!

have towed a heavy 33' camper from coast to coast and border states to border states ... have crossed most major and many minor mountain ranges and never felt like I needed it, have been running a Juice unit for about 60,000 miles and find that to pretty much be all I have needed

Jim

Local Dealer put in for me, after i reminded him that I bought the GM extended warranty also. .... I love it. Use it to keep the EGTs down and the speed up.

Yep.... same here. My dealer is great and installed mine too at no
cost.

The ODLO switch has be installed before the dealer could do the most
recent TCM program update to make the Allison "busyless".

Reference the following link (page 6):

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

It's kinda old news, but some newer members may have purchase
used trucks with the problem.

Does anyone have a picture of what the factory kit looks like?

Ryan

http://www.dieselplace.com/forum/uploads/312_guages2.jpg

I found this picture after a little searching. The factory switch is the one that is mounted where the cubby hole used to be. This is also the place for the airbag cutoff switch on regular and extended cabs.

Well, glad I found this site, it should be a salesmans first step when selling a new dmax, pointing them to this site since most have nooo idea whats going on with these trucks and I keep finding new stuff out. :banghead:

I just found the OD Lockout switch, guess it comes stock on 03 and up on the alli. hit the tow haul button once, press and hold and od lockout comes on. press again and tow haul goes off, pess and hold again and od lock out goes off.

this was almost as bad as the whole block heater cord issue...:eek: