FROM: Les SUBJECT: Re: GM Autotrac DATE: Sat, 21 Aug 1999 04:14:13 GMT ORGANIZATION: @Home Network Canada NEWSGROUPS: rec.autos.4x4 Scott Ledbetter wrote: > Let me get this straight. The standard 4x4 system in a Blazer is called > Insta-Trac? It uses push buttons, and it does NOT have a neutral? > > For $250 you get Autotrac, which has a neutral. Autotrac does have a manually > locked mode, which basically locks up a clutch that allows power to flow to the > front driveshaft. > > I still have a problem with Autotrac. First of all, nowhere can I find a > definitive description of what the system actually contains. If I am always > going to use the system in manual mode, it is just unessesary extra stuff to > break tens years down the line. I also have a hard time believing that the > system uses the same clutch as a manual transmission, as someone indicated > earlier. First of all, the t-case would end up being huge if this were true. > Second of all, a clutch needs a lot of pressure to work, and I doubt that a > solonoid system big enough to depress a clutch with a standard pressure plate is > practical, but maybe solonoids are better these days? > > Anyway, I have a hard time believing that no one can point me to a web page that > truely describes the internal workings of Autotrac. Anyone out there with this > info? The Autotrac transfercase has a clutch pack similar to an automatic transmision clutch pack with alternating friction plates and steel plates. A maximum total pressure of 2600 lbs. is applied to the clutch pack by the shift motor when at 100% duty cycle. This can deliver up to 800 ft.-lb. of torque to the front axle. The shift motor operates a eccentric cam inside the case that rides against one end of a clutch lever to apply pressure to the clutch pack. In 4Hi mode, the automatic transfer case module (ATCM) releases the shift motor brake and applies full duty cycle to the shift motor, fully applying the clutch pack. The ATCM stops the pulse width modulated signal to the motor and applies the motor brake to keep the shift motor from rolling back to the 2hi position. In auto 4wd mode, when front and rear driveshaft speed differential is detected by the driveshaft speed sensors, the ATCM releases the shift motor brake and applies full duty cycle to the shift motor which fully applies the clutch pack to bring front driveshaft speed up to the same speed as the rear driveshaft. The ATCM reduces pressure on the clutch pack if no slippage is occuring, returning the transfer case to 2wd . If a predetermined amount of slip is detected (15 rpm at 50 kph) the ATCM will then apply the required amount of pressure to equalize front/rear driveshaft speeds. The ATCM changes the duty cycle every 48 milliseconds until a slip balance point is achieved. FROM: "Thomas Wilk" SUBJECT: Ford Control Trac vs. GM Autotrac (was: GM autotrac) DATE: Sat, 21 Aug 1999 10:10:47 -0400 ORGANIZATION: AT&T WorldNet Services NEWSGROUPS: rec.autos.4x4 Les, Keeping in mind that both GM and Ford use Borg-Warner transfer cases, can it be assumed that the Ford Control-Trac uses the same type of system? Functionally, they sound about the same. Both utilize the clutch system and both have an auto mode that operates the clutch to engage the front drive train when wheel slip is detected. Time will tell how rugged this system is, but I do know that Automatic transmissions have shown their ruggedness over the years, for the most part. Tom Wilk sponge1000@worldnet.att.net FROM: Steve Winters SUBJECT: Re: Ford Control Trac vs. GM Autotrac (was: GM autotrac) DATE: Sat, 21 Aug 1999 11:57:23 -0700 ORGANIZATION: Cadence Spectrum Design NEWSGROUPS: rec.autos.4x4 Thomas Wilk wrote: > > Les, > > Keeping in mind that both GM and Ford use Borg-Warner transfer cases, > can it be assumed that the Ford Control-Trac uses the same type of > system? Functionally, they sound about the same. Both utilize the > clutch system and both have an auto mode that operates the clutch to > engage the front drive train when wheel slip is detected. > > Time will tell how rugged this system is, but I do know that Automatic > transmissions have shown their ruggedness over the years, for the most > part. > I was under the impression that GM and Dodge use New Process transfer cases manufactured by New Venture Gear, a joint venture of GM and DCC. The same for manual transmissions. NV3500, NV4500, and now NV5600. I have no idea where Ford gets their drive train components, but BW seems to be a good choice. -- Remove "*" from address to reply. Cheers, Steve 82 Z28 305 4 speed For Sale 00 SS On Order 96 K1500 The opinions expressed here are mine alone and do not represent those of my employer or any one else. "It riles them to believe that you perceive the web they weave..." Moody Blues FROM: "Thomas Wilk" SUBJECT: Re: Ford Control Trac vs. GM Autotrac (was: GM autotrac) DATE: Sat, 21 Aug 1999 16:06:42 -0400 ORGANIZATION: AT&T WorldNet Services NEWSGROUPS: rec.autos.4x4 Steve Winters wrote in message news:37BEF693.2ACA@cadence.com... > > I was under the impression that GM and Dodge use New Process transfer > cases manufactured by New Venture Gear, a joint venture of GM and DCC. > The same for manual transmissions. NV3500, NV4500, and now NV5600. > I have no idea where Ford gets their drive train components, but BW > seems to be a good choice. > -- > Remove "*" from address to reply. > > Cheers, > Steve > 82 Z28 305 4 speed For Sale > 00 SS On Order > 96 K1500 > The opinions expressed here are mine alone and do not represent those of > my employer or any one else. > > "It riles them to believe that you perceive the web they weave..." > Moody Blues Steve, Thanks for the update. I checked around a bit and found that the Borg-Warners are primarily used by Ford, with a couple of GM applications for different models. It sounds like they do use a similar setup, though. I had looked at a web site that listed the applications of various BW units, and a couple were used in GM products. I hadn't studied the page well enough to realize that only a few GM products used BW transfer cases. That of course makes sense, since GM is part of the New Process venture. Why would they make them and not use them. BTW, that site is http://www.diverco.com/borg.htm . They may have listings for other units as well, but I haven't had time to explore it further. Tom Wilk sponge1000@worldnet.att.net FROM: dmwil1@cs.comnocrap (Dmwil1) SUBJECT: Re: Ford Control Trac vs. GM Autotrac (was: GM autotrac) DATE: 21 Aug 1999 21:34:52 GMT ORGANIZATION: CompuServe (http://www.compuserve.com/) NEWSGROUPS: rec.autos.4x4 >Steve, > >Thanks for the update. I checked around a bit and found that the >Borg-Warners are primarily used by Ford, with a couple of GM >applications for different models. It sounds like they do use a >similar setup, though. I had looked at a web site that listed the >applications of various BW units, and a couple were used in GM >products. I hadn't studied the page well enough to realize that only >a few GM products used BW transfer cases. That of course makes sense, >since GM is part of the New Process venture. Why would they make them >and not use them. > >BTW, that site is http://www.diverco.com/borg.htm . They may have >listings for other units as well, but I haven't had time to explore it >further. > >Tom Wilk >sponge1000@worldnet.att.net > My Silverado's transfer case is a New Process. That company is jointly owned by Diamler-Chrysler and GM. Dan Wilson 93 YJ 2.5 96 4Runner 99 Silverado Z71 FROM: pwcman@aol.com (PWC man) SUBJECT: Re: Ford Control Trac vs. GM Autotrac (was: GM autotrac) DATE: 22 Aug 1999 03:57:10 GMT ORGANIZATION: AOL http://www.aol.com NEWSGROUPS: rec.autos.4x4 >Keeping in mind that both GM and Ford use Borg-Warner transfer cases, >can it be assumed that the Ford Control-Trac uses the same type of >system? The GM auto trac uses the NP208 transfer case, not a borg-warner unit.