Transfer Case COntrol Module Problem?

[02 Yukon Guy]

I have a 2002 GMC Yukon XL 2500 SLT. When I turn the wheel making a sharper left or right turn, I get a slight grinding noise coming from the left front tire area. I've had all wheel bearings replaced. Had a mechanic friend of mine take a look at it. He says he's thinking the transfer case control module is bad. He's thinking the TCCM is telling the left front axle to 4WD engage. Can this TCCM just be re-programmed by a dealer, or will it need to be replaced? I've found a Dorman TCCM that fits this vehicle for $137, with a $200 core charge. Dorman says that it is a refurbished TCCM and does not have to be programmed by a dealer. It's plug and play and ready to go at install. Anyone ever had any dealings with this? Anyone familiar with the Dorman TCCM's? Thanks in advance for all help.

 

[Fless]

Which transfer case do you have? Get the NPx RPO code from the glovebox or post a pic of your 4x4 dash switch.

It would be easy to tell with a Tech 2, to see if the differential actuator is being commanded to engage the diff when in/out of 4wd.

I have not dealt with the Dorman replacement but have heard the same about not having to program it to the vehicle.

 

[02 Yukon Guy]

Which transfer case do you have? Get the NPx RPO code from the glovebox or post a pic of your 4x4 dash switch.

It would be easy to tell with a Tech 2, to see if the differential actuator is being commanded to engage the diff when in/out of 4wd.

I have not dealt with the Dorman replacement but have heard the same about not having to program it to the vehicle.

I will try to get that info ASAP. Thank you so much for the quick replay and your help.

 

[Fless]

A couple of other things to consider. The way I understand that the diff works, the TCCM can't engage one side and not the other; it simply tells the front diff actuator to engage the whole diff.

What is the condition of the CV joint in the LF half shaft? Seems like that would be a more likely culprit, but maybe your mechanic checked that along with the hubs.

I assume that this happens in 2wd. Don't do this for very long, but as you take a hard turn compare the noise/binding on dry pavement in 2wd and 4hi. Do you notice any difference (between 2wd and 4hi) in how much the drivetrain binds? You should get some drivetrain "hop" in 4hi. It should be very pronounced in 4hi but there shouldn't be any binding in 2wd.

Lastly, what is the condition of the differential itself? Fluid level, fluid condition? When was it changed last? Any leaks from the seals to the half shafts?

Let us know what you find.

 

[JetBlackNali]

Never had much luck with anything from dorman, especially electrical items.

But as said above when the diff is called to work its the whole diff and not each side that engages.

# 6,8,and 32 complete the front diff engagement.

 

[02 Yukon Guy]

A couple of other things to consider. The way I understand that the diff works, the TCCM can't engage one side and not the other; it simply tells the front diff actuator to engage the whole diff.

What is the condition of the CV joint in the LF half shaft? Seems like that would be a more likely culprit, but maybe your mechanic checked that along with the hubs.

I assume that this happens in 2wd. Don't do this for very long, but as you take a hard turn compare the noise/binding on dry pavement in 2wd and 4hi. Do you notice any difference (between 2wd and 4hi) in how much the drivetrain binds? You should get some drivetrain "hop" in 4hi. It should be very pronounced in 4hi but there shouldn't be any binding in 2wd.

Lastly, what is the condition of the differential itself? Fluid level, fluid condition? When was it changed last? Any leaks from the seals to the half shafts?

Let us know what you find.

Fless, thanks for your replies. My mechanic has checked the CV joints, wheel bearings, hubs, etc, which is what we thought would be the problem early on. All were found to be OK. Fluid levels and condition of transfer case has been checked and found to be in good condition. My mechanic has ordered the Dorman TCCM for my suburban, so, I will let everyone know what I find out ASAP. Thank all of you so much for all of your help.

 

[Fless]

Please do check back; I'm curious as to the solution.

 

[02 Yukon Guy]

So, first of all, my apologies for taking so long to reply back on my thread. My mechanic says he thinks the Dorman pre-programmed TCCM has fixed my issues. He still has my suburban working on other issues, but says he's been driving it some (as I asked him to do) and there seems to be no more grinding noise coming from the front of the suburban. I'm keeping my fingers crossed that this has my problem fixed. Thanks to everyone for all their help.

 

[02 Yukon Guy]

 

[02 Yukon Guy]

The above post was the sheet describing the TCCM that was bought for my 2002 GMC Yukon XL 2500. So far, (fingers crossed) it seems to have fixed my problem. I have not had any troubles since my mechanic performed the install. Can't complain about the price. Much better than the cost of taking it back to the dealer for a re-program (as long as it stays fixed!). Just wanted to post the info that some of you had asked for. Hope this helps someone.

 

[Fless]

Good to hear, let us know how things go in the long run.

Did you send in your old one for the core? Pretty pricey if not. If I were to do that I'd probably grab a upull box for a few bucks and use it for the core, just in case my old one was still good.

 

[02 Yukon Guy]

Good to hear, let us know how things go in the long run.

Did you send in your old one for the core? Pretty pricey if not. If I were to do that I'd probably grab a upull box for a few bucks and use it for the core, just in case my old one was still good.

Yes sir, I did send my old one back in for the core.

 

[Rocket Man]

Thanks for reporting back, I’ve never heard of the TCCM doing this so that’s good to know.

 

[Fless]

Thanks for reporting back, I’ve never heard of the TCCM doing this so that’s good to know.

I never have either.

I have a somewhat weird thing happening with my '04. If I select 4x4 mode, the mode light on the switch changes to that, but the Tech 2 shows it switches for a second to 4x4, then goes to Auto. Same in 4LO, it gears down but not in 4wd. Functionally that's the way it works (as Auto, never full time 4x4), but the switch doesn't indicate that. I'm suspecting the encoder motor but haven't had a good chunk of time to really isolate it. I know that GM makes a newer TCCM module for this system.