hi all
i had bought some new tools and a 3 ton floor jack as i continue to experiment with wrenching. i have a grass yard and i had the jack under the truck so i could lift both front wheels off the ground. i was using the center of the transmission housing cross member as the jack point. i didn't have a board under the jack either, so the jack couldn't move on the grass. after i had the truck partway jacked up i heard this creaking groaning noise like something gave way. it did not sound good. i let the truck down immediately. i can't find any damage and the vehicle seems to drive fine. i'm wondering what i could have damaged.
thanks

Something doesn’t make sense - what do you mean by “center of the transmission housing”?

So you were almost in the center of the truck? If so that is a lot of weight to put on that crossmember as you are lifting a big percentage of the weight of the vehicle, especially for a Northeastern truck. Hopefully the noise was from the jack sinking into the ground at an odd angle.

well just behind the cv boot there is a big metal piece of frame that kinda drops down a bit and attaches to the rear of the lower control arms. i was just under there looking but i can't see anything bent at all. is it possible as i was lifting the truck up that it maybe makes a sound as pressure is relieved from the suspension?

maybe the jack made the noise, i didn't think of that. i ended up jacking from the centre piece that mounts the front of the lower control arms (i think). apologies for this low quality thread.

I jack from that crossmember all the time, it was probably just a suspension squeak.

I think the noise was from the jack plate sliding on the cross member.

That being said when using a floor jack, the jack HAS TO BE ABLE TO ROLL..OR the truck has to be able to roll, which I don't recommend, the vehicle rolling is very dangerous, Floor jacks are designed to roll as the vehicle goes up, if it doesn't roll and the vehicle is staying stationary the jack plate WILL try and move on the frame/jacking point...something has to give.

I also have a dirt/grass driveway...but when I used my floor jacks I have a 24" X 72" piece of 3/4" plywood that I put down for the jack which is MUCH better than on dirt...BUT even this is not the best because of the tremendous weight of a vehicle can cause the jack wheels to compress the wood and still not roll easily, so I also use a scrap piece of 3/16" steel plate on top of the plywood that I picked up from a local metal shop which will allow the jack to roll properly, the steel plate is not as big as the plywood because it's not cheap even for a piece of scrap and it a bit heavy, my steel plate is 14" X 42", plenty big enough for the jack to sit on and still have room to roll forward as I jack it up.

I have the plywood as long as it is so it sticks out from under the vehicle and I can still set the jack on it to roll it under the vehicle.


Also you need to use jack stands once you get the vehicle jacked jump..DON'T Trust just the jack as it can slip, here again you need a good piece of wood for each jack stand to sit on when on dirt, even when I put all the weight of the vehicle on the jack stands I also keep the jack in place and with a little bit of weight on it, you can never be too careful when crawling around under a 4000 to 5000 lb vehicle!!

thanks for this. it definitely could have been the jack plate sliding. it's got a rubbery material on top so it would make sense. i i didn't realize the jack needed to roll and it wasn't able to move in the grass so the jack plate would have been forced to slide. last night i got a setup rigged up with plywood as you described. also have jack stands but i didn't bother with them because i wasn't under the vehicle and only needed it up enough to freely turn the wheels (was manually pumping the power steering fluid out). should i always use jack stands even in these cases to save strain on the jack?

i've got the 3 ton arcan jack from amazon/costco. when i jacked with the plywood from the front crossmember (where the skid plate attaches) i had better luck. i've got a 3 inch lift so the tires barely come off, might use a few more sheets of plywood next time i jack it up.

I would always at least have the jack stands under there in case the jack slips, even if you're not under any part of the vehicle, the floor jack itself could do major damage to other parts of the vehicle if it slips off the jacking point, just imagine it busting your oil pan, exhaust pipes, transmission, etc. etc.

Is the factory skid plate in place? It has a reinforced part designed to be the front center jacking point (round opening in the pic below).



Oh, and everything @AuSeeker said. I completely missed that your floor jack couldn’t roll.