tranny modulator

Reply

  #1  
Old 06-08-11, 07:08 PM
Member
Thread Starter
Join Date: Feb 2010
Location: U.S.A.
Posts: 373
tranny modulator

Do the newer vehicles like a 2002 chev blazer still have a vacuum modulator on the tranny. I check the fluid levels on Saturday like I do every week on my wife blazer. She either forgets, doesn't want to get dirty, or just doesn't have time, so I do it to make sure it gets done. And not like my mother inlaw, she check the oil when the light come on. I checked all the levels, everything was fine. But come Friday afternoon, the blazer won't move, and it took 3 quarts just to get it to limp home, and it smelled really burnt. After the five mile trip it was dark brown. There is nothing on the ground, did the modulator go bad, and suck it out. According to my wife it has been shifting fine.
 
Sponsored Links
  #2  
Old 06-09-11, 04:20 AM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,513
4L60E tranny I believe. Don't think that has a vacuum modulator; my 4L80E doesn't. That's a lot of fluid loss if you're checking it routinely. No signs of leakage underneath?

For sure you need to do a fluid and filter service on it and take it from there. Three quarts low is really low on a transmission.
 
  #3  
Old 06-09-11, 04:26 AM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,513
Found some interesting info here:

FYI 4L60E common problems / failures | GM Truck Headquarters

Check item #27 especially.
 
  #4  
Old 06-09-11, 06:47 AM
Join Date: Jan 2007
Location: North Central Indiana
Posts: 905
And no they havent used a modulator for several years.
 
  #5  
Old 06-09-11, 12:45 PM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,513
Wrench, are vac mod's used on anything anymore? I'm guessing their function was overtaken by electronics.
 
  #6  
Old 06-09-11, 05:37 PM
Member
Thread Starter
Join Date: Feb 2010
Location: U.S.A.
Posts: 373
I was just wondering, I had a 69 impala that had a bad modulator, and it would suck the fluid out. But on that you could see it,m it would lay down one heck of a smoke screen, and smell real bad to. But there was no smoke from the blazer, the level was good one week, and gone the next. The freight truck is making a delivery this afternoon, is there anything I should be checking before I install it. The shop has already told me it was bad, but I can save $1,00.00 doing it myself. I got all the tools, and know how, just haven't done one in about 20 years.
 
  #7  
Old 06-11-11, 06:31 AM
Join Date: Jan 2007
Location: North Central Indiana
Posts: 905
You are correct Tow electronics have taken over.
 
  #8  
Old 06-11-11, 07:22 AM
the_tow_guy's Avatar
Group Moderator
Join Date: Feb 2001
Location: SW Fla USA
Posts: 11,513
You ordered a replacement trans, I take it? I would flush the tranny cooler lines that run to the radiator (or external cooler) to make sure they're clean and flowing.
 
  #9  
Old 06-16-11, 09:55 PM
Member
Thread Starter
Join Date: Feb 2010
Location: U.S.A.
Posts: 373
I have a update on the tranny that may be helpful to some one else in the future. After R&R of the tranny, I tore the old down to see what I could find wrong. As it turns out, the seal on the front of the clutch basket had a nick in it, and wouldn't hold pressure and leaking fluid. There is no vacuum modulator any more, but on 4 wheel drive, there is a vacuum control valve that controls the front hubs. And that went bad, and sucked the fluid out, that the basket seal was leaking and burnt it in the engine. That is why there was no fluid leaking on the ground, it was burning it as fast as it was leaking. I don't know if a piece of the clutch nicked the seal, or if the clutches broke up after they lost fluid. Now I am just waiting on some parts, and I will have a spare tranny if needed.
 
  #10  
Old 06-17-11, 07:03 AM
Join Date: Jan 2007
Location: North Central Indiana
Posts: 905
Thanks for posting back,it could be helpful to others. It is common to look for one cause for a problem,but many times it is a combination of things and that makes it tough to diagnose.
 
  #11  
Old 06-17-11, 07:25 AM
billys68ss's Avatar
Member
Join Date: May 2003
Location: USA
Posts: 1,459
That switch is in the transfer case though. I highly doubt that it was taking fluid from the trans unless wildly enough there were leaks at both rear trans seal and front t/case seal without external leakage. Rather unheard of IMO. There is no way for that trans to get fluid into the engine otherwise. Im not saying you dont know what you are talking about, but just speaking from personal experience.
Billy
 
  #12  
Old 06-18-11, 02:52 PM
Member
Thread Starter
Join Date: Feb 2010
Location: U.S.A.
Posts: 373
Well it may be strange and unheard of. But that is the way things seem to happen to me, if it wasn't for bad luck, I won't have any luck at all. And if you do happen to take one of these trannies apart, it is recommended you change the clutch basket, the neck is weak, and have been known to brake off.
 
Reply


Thread Tools
Search this Thread
Display Modes
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 02:12 AM.