# 4wd won't engage, 2000 silverado **URL:** \ **Category:** Shift518 Automotive\ **Created:** [November 25, 2013, 9:53am UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979 "2013-11-25T09:53:44Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![88slowmarro](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/88slowmarro/32/6339_2.png) [@88slowmarro](https://forums.speedlife.net/u/88slowmarro)\ **Post date:** [November 26, 2013, 9:20am UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979/21 "2013-11-26T09:20:30Z")
Not always ---
**Author:** ![toomanycamaros](https://avatars.discourse-cdn.com/v4/letter/t/7993a0/32.png) [@toomanycamaros](https://forums.speedlife.net/u/toomanycamaros)\ **Post date:** [November 26, 2013, 9:28am UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979/22 "2013-11-26T09:28:48Z")
> [@Woot, go newegg, F NYS!!](https://forums.speedlife.net/t/woot-go-newegg-f-nys/53683/8): > > it won’t work sitting in the driveway/going down the road so getting stuck and then trying it is not my problem lol > > it’s gotta be a problem in the diff, I just have this mindset that if it’s in the diff it should be making some kind of bad sound. Am I so wrong to think that? What Waite said. For all you know somebody could have had it apart and reassembled the selector mechanism incorrectly. Just make sure that the front and rear shafts are turning at the same speeds when the t-case is locked in. If your sure it’s an issue with the diff and want to pull it out I could probably help you split it open and figure out your problem. ---
**Author:** ![Boxersix](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/boxersix/32/6327_2.png) [@Boxersix](https://forums.speedlife.net/u/Boxersix)\ **Post date:** [November 26, 2013, 6:57pm UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979/23 "2013-11-26T18:57:13Z")
> [@AKA Rally 2008 Photos / Discussion - new video post 119](https://forums.speedlife.net/t/aka-rally-2008-photos-discussion-new-video-post-119/53578/54): > > If the light is lighting up etc all the servos are engaging ! Need to see if driveshaft turns . If shaft turns and light is lit up he prolly has a issue in the diff If its in 4wd at the switch but the propshaft still rotates by hand with four wheels on the ground the issue is in the tcase orwith the servo. The front end diff will not lock up until the tcase servo tells it to do so. Works this waywith that 4wd-auto crap as it kicks the front diff in/out of engagement as the wheel speed sensor input is monitored for slip. The light in the dash is controlled by a feedback signal sent from the tcase servo, so the light will illuminate even if the case isnt locked or the front end locked. IE, on my '01 Jimmy the front end of my truck is still vacuum controlled via a vacuum servo under the right side battery tray, but the tcase shares the same servo unit. My light would ome on in the dash, propshaft locked, but font end still not loked due to a vacuum leak in the system. Full electric on the 1500-2500 is still the same except font end gets a signal from the servo instead of vacuum source. The tcase servo do go bad often too, especially if its not installed correctly. Its all junk really. Its why there are manual conversions available for them. ---
**Author:** ![88slowmarro](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/88slowmarro/32/6339_2.png) [@88slowmarro](https://forums.speedlife.net/u/88slowmarro)\ **Post date:** [November 27, 2013, 4:50am UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979/24 "2013-11-27T04:50:27Z")
That won’t light up I till all switches say go , it’s wired in series so if it’s not all in 4wd that light won’t turn on . So if main servo on axle says no light won’t turn on , if switch at t case don’t work light on dash won’t light etc . That’s y there is a delay in it lighting up as that front servo is a little slow . ---
**Author:** ![toomanycamaros](https://avatars.discourse-cdn.com/v4/letter/t/7993a0/32.png) [@toomanycamaros](https://forums.speedlife.net/u/toomanycamaros)\ **Post date:** [November 27, 2013, 9:42am UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979/25 "2013-11-27T09:42:32Z")
I would have to look at the trucks RPO to know which manual t case setup he has but you 2 are thinking of the old school vaccum actuated system that was only in the S trucks at that point. His should be controlled by a switch on the t case that sends a signal to a module when should shift the tcase. Then the module engauges the front diff actuator. No vaccum system involved. However I would need an RPO code to look it up correctly. ---
**Author:** ![JSEnclosures](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/jsenclosures/32/6678_2.png) [@JSEnclosures](https://forums.speedlife.net/u/JSEnclosures)\ **Post date:** [December 19, 2013, 6:16pm UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979/26 "2013-12-19T18:16:17Z")
Thanks to Will, truck is fixed. Thanks so much dude ---
**Author:** ![toomanycamaros](https://avatars.discourse-cdn.com/v4/letter/t/7993a0/32.png) [@toomanycamaros](https://forums.speedlife.net/u/toomanycamaros)\ **Post date:** [December 19, 2013, 6:45pm UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979/27 "2013-12-19T18:45:08Z")
> [@NYIRP meet Friday 8/22/08 \* now with times\*](https://forums.speedlife.net/t/nyirp-meet-friday-8-22-08-now-with-times/53552/62): > > Thanks to Will, truck is fixed. Thanks so much dude No problem buddy, let me know if there are any more problems you need a hand with. ---
**Author:** ![offroadzj](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/offroadzj/32/6428_2.png) [@offroadzj](https://forums.speedlife.net/u/offroadzj)\ **Post date:** [December 20, 2013, 12:23pm UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979/28 "2013-12-20T12:23:47Z")
So what was it? ---
**Author:** ![JSEnclosures](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/jsenclosures/32/6678_2.png) [@JSEnclosures](https://forums.speedlife.net/u/JSEnclosures)\ **Post date:** [December 20, 2013, 12:45pm UTC](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979/29 "2013-12-20T12:45:32Z")
previous owner (or someone previous to me) assembled the axle extension housing wrong. there was a plate on the wrong side of the gear preventing it from pushing the fork over so lucky for me no new parts were needed, so the only thing I had to buy was 2 quarts of diff oil. Couldn’t have asked for a better outcome [Previous page](https://forums.speedlife.net/t/4wd-wont-engage-2000-silverado/267979.md?page=1)