Neutral to reverse slams and knocking

[Jtaylor28752]

02 Yukon 4wd 5.3/4l60e.
Recently had transmission rebuilt had done issues with the guy that did it and had to take it back to him twice now. Anyway, the day i got it back all forward gears shift fine and going from park to any gear does fine. When going from neutral to reverse it delays going into gear and when it does engage you can hear 3 or 4 knocks then just slams in jerking the truck. Hopefully the video will load. The guy who rebuilt says everything is new and claims its the transfer case, another guy just quick diagnosis says it seems like a solenoid pack. And reading stuff on here sounds like it could be any of those plus tps, maf, pcm or number of things. Any help would be appreciated thanks.

 

[Jtaylor28752]

Watch "Neutral to reverse slam and knocking" on YouTube

Link for video

 

[OR VietVet]

That noise sure sounds like is resonating from the driveshaft. If you shift from drive to reverse and then back to drive, what is the noise like if any at all? But if noise is from there it still does not address the delay problem. I am assuming that noise was not there before and was not why the trans was rebuilt anyway, right?

 

[Wylie_Tahoe]

Likely not an engine sensor, as in TPS MAF etc, unless one is creating a high idle. The delay points to valve body or solenoid. A scan tool would allow you to see some of whats going on there.

What about part to reverse? Should have the same reaction, good or bad. Whats the engine idle in park and neutral? Normal range? id raise the rear wheels and check the drive shaft and diff for slop. With the trans in park, any slop in the t-case will be noticeable.

 

[Jtaylor28752]

From park to reverse it does it the same, only does it when its warm, when its cold it doesnt do it at all. No delay no knocking nothing. I had it rebuilt because the delay was there but instead of the multiple knocks it was one loud smack and jerk and eventually broke the planetary gear. Engine idle is normal in both park and neutral

 

[OR VietVet]

Now we are finally getting down to the nitty gritty. The builder needs to get back inside the trans. You are having almost the same problem as you started with.

 

[Rocket Man]

Now we are finally getting down to the nitty gritty. The builder needs to get back inside the trans. You are having almost the same problem as you started with.

That doesn’t necessarily mean the trans was the original issue, it’s possible that the original issue caused the trans to break. If the transfer case is causing the clanking going into reverse, it needs to be diagnosed and repaired first and then the trans needs to be checked to see if it got damaged again. @Jtaylor28752 I would pull the TC and have it checked out before going any further. It’s unlikely it’s a driveline issue judging from your description of it happening only going into reverse as well as only when it’s warm. To me, all signs point to the TC but it’s hard to tell for sure.

 

[OR VietVet]

That doesn’t necessarily mean the trans was the original issue, it’s possible that the original issue caused the trans to break. If the transfer case is causing the clanking going into reverse, it needs to be diagnosed and repaired first and then the trans needs to be checked to see if it got damaged again. @Jtaylor28752 I would pull the TC and have it checked out before going any further. It’s unlikely it’s a driveline issue judging from your description of it happening only going into reverse as well as only when it’s warm. To me, all signs point to the TC but it’s hard to tell for sure.

Good call. I completely agree. I am ASSUMING that the builder allowed for that and checked but as you said, it could have been over looked.

Kind of like blown head gaskets. Rare to just have a head gasket go bad without something else causing an overheat and then damage the head gasket.

 

[Erickk120]

Put it on neutral, chock the wheels, and turn both shafts by hand,then rock them hard side to side. see if you can pin point anything similar back to the tcase, my Tcase started knocking a little recently and that is how i concluded it was coming out of it and not the slip yoke as it did it without the rear shaft or front shaft, when i did one at a time.

Here is what mine sounds like atm, but I will be doing a 246 to 241 manual tcase swap here in the next few weeks, just waiting on parts, I might even do a build thread, if I get the energy.

 

[Jtaylor28752]

Well i took it to the guy that checked the transfer case when the trans originally went bad, he didn't think that it was coming from the T-case. I also can't get it to duplicate it again after the first couple day. Now though the delay has turned into it won't engage reverse unless I give it a little gas. Which again is how it was doing originally when it broke the planetary. Idle speed is roughly 500 I bought a new tps today and going to run some seafoam through it and clean the throttle body.