Intermediate Steering Shaft

kmsbryans2018

New member
Joined
Oct 26, 2020
Messages
9
Reaction score
0
Points
1
I have a 2011 GMC 2500HD 4wd with the LML Duramax. I had to replace the glow plugs due to codes, and in order to change out the number 4 glow plug (this was one of the ones throwing a code, I had to remove the upper intermediate steering shaft. The slip yoke, portion of the shaft does not want to slip. I managed to get the thing out of the truck, using a pair of channel locks and a hammer to collapse it. I figured that the slip yoke was frozen and needed to be disassembled, some rust cleaned up, and then relubricated. Boy was I surprised to see a splined bushing made of plastic. Everything appears to be straight and true but the fit of the plastic is so tight that the yoke does not slip and I can't finish the install because I can't get it to slide open enough to place the bolts back into both ends. I'm used to shafts like this having one larger spline which this one does and I ensured that it was properly aligned. Still it is super tight and I can only get it to slide with a hammer.

I am unemployed due to my health so running out and purchasing a new part is not an option especially since this one appears to be in great shape other than not wanting to slide without a hammer involved. I can't seem to find a good direction to attack it to extend the shaft via the hammer and channel locks that I used to collapse it for removal. Plenty of room to swing the hammer and collapse it, zero room to swing the hammer and extend it. I have considered removing it again and shaving the plastic splines ever so slightly in hopes of creating some clearance. I know you don't want any play in it obviously. I'm just not sure if there's a tool I can get ahold of that will allow me to force it open in place on the truck or what. Any ideas on how to get this thing to slide a bit more freely or at least just back into place?
 

zora

Staff member
Joined
Apr 24, 2012
Messages
4,190
Reaction score
51
Points
48
Not sure if this is the same but they have a problem fitting a shaft and apply grease before assembly . There are more videos showing the installation that may help.
 

kmsbryans2018

New member
Joined
Oct 26, 2020
Messages
9
Reaction score
0
Points
1
Thanks for the reply, however this video does not apply at all to the problem I posted in this thread. They had a problem making the connection between the upper intermediate steering shaft and the lower intermediate steering shaft (which the lower intermediate steering shaft remains attached to the steering gear box during this entire video. Also, it was not necessary for me to remove it in order for me to change the number 4 glow plug. It is not necessary to remove the lower intermediate steering shaft unless you have a worn out ujoint or you need to remove the steering gear box. Once the upper and lower shafts are disconnected from one another the lower shaft simply falls downward and sits out of the way next to the frame). This video is not at all what I'm experiencing as my connection, that they showed as problematic for them in the video, is a proper slip fit. Mine has not been overtightened as the video narrator described as being the problem they experienced. I believe I'm the first to ever do anything with the upper intermediate steering shaft on this truck since the day it was installed at the factory.

In this problem I'm experiencing and seeking help for, there are in actuality "3 shafts" involved. Yes, "Three" not Two.

"How can that be, there's only 2 shafts, the upper and lower intermediate steering shafts involved in this problem for which you are seeking help? Your math doesn't add up, are you using common core to count these shafts?"

Great questions, fair questions even, the answers are simple. One shaft (the lower intermediate steering shaft) is a solid shaft, the other (the upper intermediate steering shaft) is actually two splined and keyed half shafts that are supposed to slide in and out of one another just like a properly maintained tractor PTO Drive shaft. The video doesn't show everything clearly but since I am intimately familiar with these parts (having fought with them for several hours), I'll explain as best I can.

The lower intermediate steering shaft is a solid length of tubing that has a crush zone built into one end (that's the funny accordion looking area near the connection point for the upper shaft). The lower end of this shaft that connects to the steering gear box has the u-joint and yokes.

The upper intermediate steering shaft is in reality 2 splined shafts in one package. Starting from the 2:07 - 2:10ish marker you can see the upper intermediate shaft "new vs. old" first in their collapsed position. Then at the 2:11ish marker of the video they show them extended. The two halves of the upper intermediate steering shaft should slide in and out of one another, again I say much like a well maintained PTO driveshaft for a tractor implement such as a Bush Hog mower. Each half shaft is splined and keyed to fit one another. One half has internal splines, the other half (the end with the ujoint) has matching external splines. I say "keyed" which means that both halves have one spline that is thicker than the rest.

These 2 halves should slide in and out from one another without the need for excessive force. Force such as the use of a pair of channel locks to hold one half and then a hammer to hit the channel locks in order to get the intermediate steering shaft collapsed enough for removal from the vehicle. However, as I said mine are not sliding without alot of hammering as described. I have checked for straightness, no bending, nor twisting, nor wavyness detected. I have checked for signs of burrs in the splines. The internal splines of the lower half of this shaft are made of metal, they appear to be clean, free of debris, smooth, and true (a.k.a. straight as an arrow). They are not leaving any signs of scraping or gouging into the external splines of the upper half which are formed by the aforementioned plastic bushing from my original post. But they do not slide as they should. When I first saw the plastic splines I immediately began looking for debris clogging things up. When I got the 2 half shafts separated from one another I expected to find dirt, dust, or some other crud gumming things up, stopping their sliding motion. None of that appeared to be the case. The splines had a slight coating of lubricant which still felt slick not sticky which would have also explained the tightness. I used copious ammounts of CRC's chlorinated brake cleaner, the really good cleaner (so good it will clean your skin off your bones if you're not careful), to ensure cleanliness of the internal and external splines. I allowed the brake cleaner plenty of time to off-gas as I knew that it could possibly cause the plastic to swell. Still no sliding even attempting application of some WD-40 and then also PB-Blaster. No dice, also absolutely "NO LOVE" from this GM original factory part.

Once again, referring strictly to the upper intermediate steering shaft, the lower end of the lower half of this shaft is what makes the connection under the hood to the upper end of the lower intermediate steering shaft. The upper end of the upper half of this shaft has the ujoint and yokes built onto it, it passes through the firewall, and is what makes the connection inside the cab under the dash to the steering column.

I'm not sure who they had install this thing at the factory on the date of manufacture but I wouldn't want to piss that person off if they are capable of making this thing collapse and extend for installation. Since the fit of these two half shafts which make up the upper intermediate steering shaft should be more of a friction fit than a pressed fit I honestly wonder if when they install them at the factory if the upper intermediate steering shaft is already set to it's proper length via machine and is already installed in the cab when the cab meets the frame. This would explain how the 2 halves not sliding would have been missed in the building process. Because I can't see how any mortal could simply reach in there and make this puppy extend by sliding the lower half into the lower intermediate steering shaft. That person would need the strength of Hercules or the Hulk, neither of which are a mere mortals...

Heck I couldn't even put my full 215lbs. of body weight on it and bounce to push the halves back together. Force was necessary, lots of concentrated force from a hammer blow was needed to get them back together. If it was a matter of not having the keyed splines clocked properly to one another I could totally understand all of this. But they are clocked properly or else there would be damaged splines as that one big spline is almost twice the width of the rest.

So my problem is with getting the upper intermediate steering shaft to extend to proper length during installation back onto the vehicle. It is not the problem shown in the video between 2:15 - 2:40. In fact the narrator even stated that particular fitment issue occurs because of overtightening of the bolt that keeps the upper and lower intermediate steering shafts together. My problem is an issue with the upper intermediate steering shaft only, which again is in reality 2 half shafts that are splined and keyed to fit one another and they should extend and contract along their length.

Anybody else have any ideas what I can do to make these 2 halves slide in and out as they should?
 
Top