2WD to 4WD Grinding - Chevy and GMC Duramax Diesel Forum
01-04.5 LB7 Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

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post #1 of 2 (permalink) Old 01-07-2020, 01:05 PM Thread Starter
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devinhill92's Avatar
Join Date: Nov 2019
Location: VA
Posts: 15
2WD to 4WD Grinding

I was driving to work this morning in the snow going around 25-30 mph and engaged 4WD Hi and something grinded in the front end. It was quick and went into 4WD like normal, but I was a little concerned that I may have messed something up. I usually come to a complete stop before engaging 4WD, but unfortunately I was not in the position to do so this morning. I was under the impression that these trucks were able to shift into 4WD on the go.

Is there something I can check to make sure I didn't damage anything? I pulled off of the side of the road and made sure it went back into 2WD and then back into 4WD, and it worked like normal.

2003 Silverado 2500HD LB7 ECSB LT
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post #2 of 2 (permalink) Old 01-07-2020, 03:09 PM
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Join Date: Jan 2009
Location: West-Central Indiana
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If it was in the front end, it was probably the slide collar that engages the passenger side stub of the front differential. I'm glad that it worked afterwards, but most of the time when that happens, it shears the teeth off the slide collar or the gear, or breaks the collar. I've been in to several of them before that have done that. Normally you are fine to engage while moving, unless the rear is spinning and the front wheels are not. That is when it creates problems a lot of the time.
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File Type: jpg front diff slide collar.jpg (44.3 KB, 21 views)

Name: Matt
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