78 GMC Jimmy
1/2 ton status
Is there any reason I should not drive the rig as is, with the missing rear drive shaft? Can I just lock in the hubs and put it in 4x4, and drive it?
CK5
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Another bad U-joint????
- Thread starter 78 GMC Jimmy
- Start date
In a pinch you can but don't go on the highway and on the curves be gentle with the gas pedal and turn as little as possible, the axle Ujoint doesn't like turning under power.
I had to drive my crew cab after I broke the rear driveshaft to get home 70 miles on highway.
By the time I got home the Ujoints were both shot.
I believe you have the same angle give or take 1-2 degrees.
Us the phone in the same direction, meaning if you use the phone on the axle while looking at it from the driver side, do the same from driver side on the tcase using the other edge of the phone. Then let us know what the angles are
I had to drive my 77 home that way, 130 miles I think. Ended up replacing both u joints in the drive shaft and the ring gear was shot
I went to a different set of axle shafts, but I would have replaced those as well instead of reinstalling after seeing the damage
78 GMC Jimmy
1/2 ton status
Sheesh! Glad I asked. I guess I will leave it parked for now. I don't want to damage the front end parts. Didnt know that driving on the front end only could cause so many problems. I had a GMC Jimmy years ago that was front wheel drive, and would only transfer power to the rear when needed and only when it was in 4x4. I pulled the front drive shaft so that I could get rear wheel drive only, for the purpose of doing doughnuts.
It was probably a 203 transfer case, not front wheel drive. Complete different thing
78 GMC Jimmy
1/2 ton status
OK OK, I will go re-measure the dang angles from "only the driver side" of the rig...
I will even upload pictures showing the 20 degr.... Wait.. WTF !?!?
Pics:
Your angles are good.
You just need to have the driveshaft phased and if you see that it is smoother and not getting hot, I strongly suggest the $300 new driveshaft when you can do it.
I bet you already spent close to $100 on ujoints and countless hours, your driveshaft is still a dangerous piece.
I understand you wanted to make sure you were not destroying the new shaft with the same problem.
Now you learned a few things about driveshafts you didn’t before.
78 GMC Jimmy
1/2 ton status
Ya, I have definitely learned a lot about driveshafts due to this issue. I think that learning and testing with the old drive shaft before buying a new one is certainly the way to go. I agree, if mine doesn't vibrate or get hot - I do plan to replace it at some point when I can find one at a good price. I won't go out and spend $300 on one, but when I find a good deal - I will snatch it up. Ability to spend money is not the issue, its the net worth aspect.
Buy brand new car: Instantly lose $10K in net worth, since the car depreciates the second you drive it off the lot.
Buy a used car that is worth $10K, for the price of $700, and your net worth just went up by $9,300. You get something for a great deal, and your getting paid thousands in net worth to do it.
I won't pay $300 for a drive shaft. Hell, I only paid $170 for my first 78 GMC Jimmy, and $400 for my first 79 K5 Blazer. Its the principle of the matter. Now if the exact same driveshaft was worth $2,500 and I could get them for $300 each? Sure I will take 2.
As for U-joint costs, I would not buy expensive ones until I figured out the cause of the failure. When the last one failed, I installed a good used on that I got from a friend.
That one blew up, so I ordered a front and rear U-Joint for a total cost of $22.80 (MOOG brand, Amazon).
So far, the phase has been corrected (or 180 out). and I will grind down the rear C clip channel so that I can get a clip in there to prevent the back and fourth play of the U-joint. Angles are good. So aside from that, I think I'm ready to install the new U-joints and then see if they get hot or wobble.
Hopefully the out of phase, and free free-play in the rear U-joint was the cause of all the issues.
I appreciate all the input from everyone. If you have any more tips, I'm all ears.
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78 GMC Jimmy
1/2 ton status
So I got the driveshaft in phase (or 180 out). The dent did cause a small bend at the rear of the driveshaft, so there is a little wobble, but its definitely the most profound at the back, not the front. After driving for a mile or two, the rear U-joint is cold, and the front is HOT. The needle caps attached to the T-case the hotter, but mainly at the outer end of the cap. Took it back apart, and there are wear marks on the end of the U-joint under the cap. I took a different U-joint and bolted it to t-case without the driveshaft. I was SUPER stiff, and you could feel the needles when rotating it one way then the other. Almost like a click click click feeling. Ever mm of movement would be another bump that you could feel. CLEARLY something wrong there. I loosened the bolts, and the roughness and stiffness went away completely. If I snug them down just a little tiny bit, they almost feel normal. So for now, I snugged them just a tiny bit, and double bolted the thing. Drove it again. Still a bit warm on the front U-joint, but not as bad as before. I think I need a new transfer case yoke, as this one must be bent or something. It does have some damage from previous U-joint failures.
Anyone got a T-case yoke to sell?
Pics of the new finding can be found here, toward the end of the picture:
Anyone got a T-case yoke to sell?
Pics of the new finding can be found here, toward the end of the picture:
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78 GMC Jimmy
1/2 ton status
Crickets? Come on guys, you are the experts. What is the cause of this transfer case yoke issue? It must be deformed or something, putting an unusual angle or strain on the needle bearings when its torqued down, am I correct? Why would a U-joint be super rough and stiff when installed on a t-case yoke? I tried cleaning up the yoke with a wire brush and blasting the surfaces with Wd40 to remove dirt and to assure a clean and true mating surface. So when you put any torque on the bolts, the needle bearings start barking.
From everything I can tell, the driveshaft has nothing to do with the problem. It is a problem with the transfer case yoke. I believe this because the problem is VERY OBVIOUS even when the driveshaft is not installed on the vehicle. Why would slightly tightening these U-bolts cause the needle bearing to bind?
No amount of new angles, balancing, re-tubing, new U-joints, etc would have solved this problem.
What I'm asking is this: What will solve this problem?
From everything I can tell, the driveshaft has nothing to do with the problem. It is a problem with the transfer case yoke. I believe this because the problem is VERY OBVIOUS even when the driveshaft is not installed on the vehicle. Why would slightly tightening these U-bolts cause the needle bearing to bind?
No amount of new angles, balancing, re-tubing, new U-joints, etc would have solved this problem.
What I'm asking is this: What will solve this problem?
I can only think of 3 possibilities causing this:
From Denny's Driveshafts: https://www.dennysdriveshaft.com/c131_hardware.html
1330:
- The yoke is deformed and is therefore deforming the U-joint cap. You should be able to tell by rotating the caps in place.
- You are overtightening the U-bolts. You wouldn't be the first to smoke a U-joint this way.
- It's the wrong joint, like you have an S44 joint in a 1330 yoke. The snap ring locations should give this away.
From Denny's Driveshafts: https://www.dennysdriveshaft.com/c131_hardware.html
- U-BOLTS
- Recommended Torque to Tighten Correctly
- 1310 Series 14 to 17 Lb. Ft.
- 1330 Series 14 to 17 Lb. Ft.
- 1350 Series 20 to 24 Lb. Ft.
- 1410 Series 20 to 24 Lb. Ft.
S44:1330:
So you call the people here the experts, yet don’t listen to anything they say. You can’t fix this issue without a new driveshaft, period. A bent driveshaft is never going to last. The fact that the front joint is the hot one is irrevelant, if the shaft is bent it’s vibrating and it’s going to cause heat in a joint, could be either one. You can buy a new yoke from multiple suppliers so why buy a possibly bad used one.
78 GMC Jimmy
1/2 ton status
Thanks for the info. It is possible that the bolts were over tightened, but I cant say for sure.
I might be able to get my 1/4 drive torque wrench on it with extensions and swivels - I will try.
Pretty sure the yoke is bent or deformed or something. How do I identify the part # that I need?
I'm using a U-joint with clips on the end, and they fit properly into the drive shaft. I am pretty sure its the correct one. They T-case yoke might be designed for the other style, I'm not sure. It sure seems like the correct one but I could be wrong. How can I tell if the T-case toke is wanting other "inner clip" type U-joint?
If it's internal clip it will be machined flat on the inside.
78 GMC Jimmy
1/2 ton status
I think I understand what you mean. Like this?
Mine looks like this, with the tabs on either side that the caps touch:
Your yoke has nubs on the edge to keep the Ujoint in place and the ubolts keep it in the groove.
Are you using clips on it?
It shouldn't have any even if it comes with one.
Those ubolts are great but if you over tighten them they will squish the cap.
Are you using clips on it?
It shouldn't have any even if it comes with one.
Those ubolts are great but if you over tighten them they will squish the cap.
78 GMC Jimmy
1/2 ton status
I'm not using any clips on the T-case yoke, just the U-bolts. I think I need to replace the U-joint again, just because of the wear marks seen in the pics. I will try using VERY little pressure on the U-bolts - since any pressure seems to cause friction in the needle bearings. But how loose is too loose? Just enough pressure to eliminate any free play, and call it good with the double bolts? I don't want the bolts to come off, but I also don't want to use Locktite - hence the double bolts setup. My overall plan is to replace the driveshaft and T-case yoke at some point, when I can find a good deal on them. I need to replace that oil seal anyway, so why not put a new yoke on there at the same time. I would not mind having this old driveshaft in the back of the rig as a spare.
Is there any major risk of having them slightly too loose, if they are double bolted? Like if it call for 14-17, and I use 8?
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They'll need the spline count (probably 32), the U-joint series (probably 1330), strap/u-bolt and possibly the diameter of the sealing surface. Someone like this can tell you what you need: https://torqueking.com/product/40823/qu40823-1330-series-rear-output-yoke-32-spline-for-np205/
I would not run it loose. If there's any slop in there it's going to spit the caps out under load or start hammering things apart. It's likely the caps that were already tightened down in there are now deformed. Maybe you have some on a spare joint to swap.
I would not run it loose. If there's any slop in there it's going to spit the caps out under load or start hammering things apart. It's likely the caps that were already tightened down in there are now deformed. Maybe you have some on a spare joint to swap.
78 GMC Jimmy
1/2 ton status
I just tightened them to a "snug" level. Too tight to loosen with just your fingers, but not by a lot. There would not be any free-play, but the bolts are definitely not very tight. Sound OK for a test drive? I want to get as much testing done as possible before swapping it out. I have a spare in the rig, just in case. I have access to plenty of used ones for free, and they are only $10 on Amazon - so if a couple of them get messed up, its no biggie. I think if this one stops overheating, I can just swap it out and call it good. Thoughts?
