4L80E Tow Mode

buzzcut · 04-20-2009, 11:11 AM

I have an 2000 Silverado 2500 4X4 with a 4L80E in it. I was haveing tranny problems and a tranny guy I was referred to said it was a bad valve body. The truck has 164,000 on it. Anyway I replaced the valve body and all was good, truck shifted and drives great. So now I'm haulin a lot of firewood lately and when I push the button on the shifter to go into tow/haul mode nothing happins, no indication on the message board and no difference in shift patterns. The tow/haul mode worked before on the old valve body, anybody got a clue? Thanks, Marc

fbhart@wk.net · 04-21-2009, 03:56 AM

buzz,
i have a 2000 model 2500 series obs, 2wd, it has the 350 motor and 4L80e transmission. I assumed all 2000 model transmissions were the same, but mine does not have tow/haul.

when towing I have to shift it to 3rd so transmission will not shift into the 4th gear. Can you not do this with your transmission?

bradrhale · 04-21-2009, 06:34 AM

odd, the 00 silvy i had had a tow/haul but it was a 4l60e. you would think that with the bigger tranny, they would have the tow/haul mode.

NonGoggleGuy · 04-21-2009, 07:12 AM

1997 K3500 dually here... 4L80E... no haul switch.

buzzcut · 04-21-2009, 09:45 AM

Yeah my truck is a mixed bag of tricks, it's not labeled as a HD truck but has all the options like tranny, powersteering, and oil coolers, hydro boost brakes, heavy susp, rubber interior flooring. Anyway it also has newer gen 6.0L. I think this truck has what was called Contractor's Package, the series before HD can out later that year but who knows. I know I connected all the wiring back up after the valve body job, I'm tryin to figure out the abbreviations on the fuse box panels, I guess it's an electrical problem sense it's a switch. I though it might be a common bug so I'd ask. I have not tryed drivin in 3rd, but I'll give it a shot with this weeks haul. Thanks

hotrodpc · 04-22-2009, 10:30 AM

Certainly give the manual selected 3rd a try until you get this issue resolved, so you don't do any damage to the trans itself. So this all worked fine before the valve body change? I am not real sure on this electrical stuff. It would certianly think it has something to do with the switch. Being the trans is controlled by the ECM, I am wondering if you may have to re program the ECM to the new valve body for all the functions to work properly. It would certainly be worth a try. Did you replace just he valve body or all the switches and solenoids too?

leolkfrm · 04-22-2009, 03:07 PM

did you check the fuses and connection plugs?

hotrodpc · 04-22-2009, 10:36 PM

Yep, I would check the fuses. Someone may have grounded out a wire during installation. Although it should not have had power with the key off. I would check all fuses, connections and if of that is good, then maybe consider the reprogram. In the meantime I will see else I can find out about it.

hotrodpc · 04-22-2009, 10:48 PM

Here is something I found on another forum. This is responses to from 2 guys and a 3rd guy said, yep thats your problem.

The problem is in the switch there is small wires in there one has broke free.

Its a common problem, There's an Orange wire that usually breaks down by where the shift lever goes into the steering column under that rubber boot.

buzzcut · 04-23-2009, 09:19 AM

Thanks a lot I will check this out today and report back.

04-20-2009, 11:11 AM	#1
buzzcut Full Member Join Date: Mar 2009 Location: Kresgeville, Pa. Posts: 23	4L80E Tow Mode I have an 2000 Silverado 2500 4X4 with a 4L80E in it. I was haveing tranny problems and a tranny guy I was referred to said it was a bad valve body. The truck has 164,000 on it. Anyway I replaced the valve body and all was good, truck shifted and drives great. So now I'm haulin a lot of firewood lately and when I push the button on the shifter to go into tow/haul mode nothing happins, no indication on the message board and no difference in shift patterns. The tow/haul mode worked before on the old valve body, anybody got a clue? Thanks, Marc

04-21-2009, 07:12 AM	#4
NonGoggleGuy Senior Member Join Date: Mar 2009 Location: New York State Posts: 259	1997 K3500 dually here... 4L80E... no haul switch. __________________ Bored? Check out Project: Wreck. - The NonGoggleGuy - I'm unbelievable... believe me.

04-21-2009, 09:45 AM	#5
buzzcut Full Member Join Date: Mar 2009 Location: Kresgeville, Pa. Posts: 23	Yeah my truck is a mixed bag of tricks, it's not labeled as a HD truck but has all the options like tranny, powersteering, and oil coolers, hydro boost brakes, heavy susp, rubber interior flooring. Anyway it also has newer gen 6.0L. I think this truck has what was called Contractor's Package, the series before HD can out later that year but who knows. I know I connected all the wiring back up after the valve body job, I'm tryin to figure out the abbreviations on the fuse box panels, I guess it's an electrical problem sense it's a switch. I though it might be a common bug so I'd ask. I have not tryed drivin in 3rd, but I'll give it a shot with this weeks haul. Thanks Last edited by buzzcut; 04-21-2009 at 09:47 AM. Reason: Forgot something

04-22-2009, 03:07 PM	#7
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	did you check the fuses and connection plugs? __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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04-21-2009, 03:56 AM	#2
fbhart@wk.net Senior Member Join Date: Mar 2007 Posts: 115	buzz, i have a 2000 model 2500 series obs, 2wd, it has the 350 motor and 4L80e transmission. I assumed all 2000 model transmissions were the same, but mine does not have tow/haul. when towing I have to shift it to 3rd so transmission will not shift into the 4th gear. Can you not do this with your transmission?

04-21-2009, 06:34 AM	#3
bradrhale Senior Moderator Join Date: Apr 2006 Location: Texas Posts: 8,014	odd, the 00 silvy i had had a tow/haul but it was a 4l60e. you would think that with the bigger tranny, they would have the tow/haul mode.

04-22-2009, 10:30 AM	#6
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,145	Certainly give the manual selected 3rd a try until you get this issue resolved, so you don't do any damage to the trans itself. So this all worked fine before the valve body change? I am not real sure on this electrical stuff. It would certianly think it has something to do with the switch. Being the trans is controlled by the ECM, I am wondering if you may have to re program the ECM to the new valve body for all the functions to work properly. It would certainly be worth a try. Did you replace just he valve body or all the switches and solenoids too?

04-22-2009, 10:36 PM	#8
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,145	Yep, I would check the fuses. Someone may have grounded out a wire during installation. Although it should not have had power with the key off. I would check all fuses, connections and if of that is good, then maybe consider the reprogram. In the meantime I will see else I can find out about it.

04-22-2009, 10:48 PM	#9
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,145	Here is something I found on another forum. This is responses to from 2 guys and a 3rd guy said, yep thats your problem. The problem is in the switch there is small wires in there one has broke free. Its a common problem, There's an Orange wire that usually breaks down by where the shift lever goes into the steering column under that rubber boot.

04-23-2009, 09:19 AM	#10
buzzcut Full Member Join Date: Mar 2009 Location: Kresgeville, Pa. Posts: 23	Thanks a lot I will check this out today and report back.

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