wobble and squeak?

[vancelot69]

Let me apologize for the novel in advance. I like to be thorough when I'm asking for help. This is on my '70 Jimmy.

Ever since I got it back in April, it shifts HARD going from drive to reverse. It almost sounds like the u-joints are bad, but I can't move the driveshaft with my hand.

A few months ago, I started noticing a squeak-squeak-squeak, especially when I would let off the accelerator or drive in reverse. So, I tried to grease all the zerks I could reach on the driveshafts (the u-joints, and my driveshafts look like they have a slide coupling - see pics - the one with the transmission pan in the shot is the front shaft), but some of them wouldn't take grease, and some of the u-joints didn't have zerks on them.

After doing this, it seemed to mostly alleviate the squeaking, but it still shifted hard.

A few weeks ago, the squeaking came back, and a few days after that, the truck started getting a bad wobble around 35 MPH.

At this time, I had my wife shift into drive-reverse-drive etc so I could see if the u-joint was thunking. I thought it would be the rear u-joint on the rear drive shaft, but when she would go from drive to reverse the driveshaft would stay put, but the thunking noise was coming from the transfer case, although I couldn't tell it if was internal or if it was on the rear output shaft.

The truck has been leaking auto trans fluid, I'm not sure where, so I thought I would check the fill hole in the transfer case to see if it has been leaking into there, and when I popped it off, it immediately started gushing ATF, so I quickly put the fill plug back in.

Then I went to try to get better angles with the grease gun and try to make sure I hit every zerk and make sure they took grease. The main one I wanted to check is the front u-joint on the rear driveshaft that connects it to the t-case, but it didn't appear to have a zerk, so I was looking and looking and one of the u-joint caps looks like it's busted. (I will try to get a pic later this week. It's cold out! haha)

The wobbling makes me afraid to drive it. I can live with the squeak and hard shifting.

So, if you've read all that, thanks for sticking around!

My questions are:

Can an overfull t-case cause wobbling?
Can a busted cap on a u-joint cause wobbling?

I don't think it's anywhere else. That is, I don't think it's in the steering, or front end components (drive axle u-joints, tie rod ends, ball joints, drag link, etc.). But I guess it could be...

Thanks for any help y'all can give!

[truckster]

Overfull transfer case? Not likely to cause a wobble - the worst that will happen is leaking seals.

Busted cap on a U-joint? Definitely can cause a wobble. The caps keep the U-joint centered. An off-center U-joint means an off-center shaft. Replace the U-joint and see how it drives.

[jaros44sr]

My take on the problem is that you have drained ATF out of the trans. putting it into the transfer case through the seal at the tc mount.....not hurting tc, but your trans would need to have the level checked

You would be amazed how pressure a grease gun can make, you may have pushed one cap to one side and not the other. Replacing u joints is not a costly or difficult job. My son just did his while down for the holidays and showed me a differant way of getting the u joints out. Basically he cut the cross piece out with my angle grinder using a new 4" cutoff wheel (remove drive shaft and put in vise on the work bench) Then you can remove clips and beat the caps in towards where the cross piece was. Generally, this area is cleaner and much easier to push caps in. After the caps are out, you can clean up the area that the caps don t sit in. And then press in the new universal joint

Although i don t like to use that tool, it did work. I made him wear tight fitting safety goggles and face shield. Have you ever seen a cutoff wheel come apart. Scary sh!t...

I will still do it the old fashioned way, seems to me much safer, i don t use my angle grinder cut off unless there is no other tool in my box that will work. You tube doesn t consider the safety factors

[A1971Blazer]

A squeak, squeak, squeak.......is usually a bad U-joint.

[vancelot69]

Is this bad enough to cause my issues? I haven't looked at any of the other u-joints, or any of the other caps on this particular u-joint to see if there are any others or any worse.

[vancelot69]

Also, while I was under it taking that pic, I grabbed the drive shaft again to try to move it. I couldn't turn / twist it, and I couldn't move (rattle) it back and forth, it seemed pretty solid. Of course, it was in park, so I don't know if that matters, if I should try moving it in neutral or something.

[truckster]

If the truck is in park and that's what's holding it in position, there may be a lot of torque on the driveshaft, making it difficult to move no matter how bad a U-joint is.

I would replace that U-joint and see what that does for you.

[jaros44sr]

Originally Posted by vancelot69

Is this bad enough to cause my issues? I haven't looked at any of the other u-joints, or any of the other caps on this particular u-joint to see if there are any others or any worse.

I see something shiny down in there, i think your seal is brittle and broke, water probably got in there....time to replace them

Also, it looks like part of your groove is missing, but you won t know for sure until you get in there

[grillzy]

u joint is shot. Seal is gone needle bearings are gone too.

[cleszkie]

You didn't mention if you had a lift kit installed or not. From the pictures, it looks like you might have some sort of lift. This will affect the driveshaft angles at the transfercase and at the rear axle housing. Generally, anything equal to or greater than a 4 inch lift will require a CV joint to be used in your rear driveshaft to eliminate driveshaft vibration and continuous U-joint failures.

The hard shifting into reverse indicates an improperly adjusted carburetor. The idle RPM in neutral is too high. You can't just turn the idle screw and reduce the idle for a proper neutral idle RPM because the engine will bog down or stall when shifted into drive with the brakes on. You will need to adjust carburetor along with timing to get things right. Ideally, your idle RPM in neutral should only be about 100 RPM higher than your idle RPM in drive with foot on the brake. My idle RPM in neutral is 750 and my idle RPM in drive is 650.

[vancelot69]

When I got it, it had (still has) about a 4" lift on it.

It seems to have a 4 stage choke on it. When I first start it, it has a fairly high idle, but after 3 step downs (run a bit, hit the gas to step down, repeat, repeat), it seems to me like it's at a fairly low idle. But it doesn't have a tach, and I don't have a mechanic's tach (yet!) or a timing light (yet!), but it seems to me like both of those are next on my short list of tools to buy.

Would replacing the u-joints with cv joints require a complete drive shaft replacement, or can you get some that fit right into the existing u-joint holes?

[K5Ken]

You can get u-joints for your Blazer at any auto parts store. Drive shafts for Blazers are a little harder to find.

[A1971Blazer]

Originally Posted by vancelot69

When I got it, it had (still has) about a 4" lift on it.

It seems to have a 4 stage choke on it. When I first start it, it has a fairly high idle, but after 3 step downs (run a bit, hit the gas to step down, repeat, repeat), it seems to me like it's at a fairly low idle. But it doesn't have a tach, and I don't have a mechanic's tach (yet!) or a timing light (yet!), but it seems to me like both of those are next on my short list of tools to buy.

Would replacing the u-joints with cv joints require a complete drive shaft replacement, or can you get some that fit right into the existing u-joint holes?

A double cardan or CV joint will require a different yoke for the output on your 205 transfer case. A standard u-bolt style yoke will not work. If you've run the set-up like it is for a while it will probably be OK as long as you replace the u-joints and keep a couple of spares on hand........ and yes you would need a different driveshaft....at least the front part back to the slip joint.
If you have a driveline shop nerby, they can put together what you need or sell you the components. The on-line driveshaft suppliers are a bit pricey.......go here to see some 205 TC parts http://www.quad4x4.com/New_Process_N...rts.html#Yokes

[vancelot69]

Well, this afternoon I went out for a quick second, put it in neutral, and wiggled the driveshaft, and the u-joint on the rear at the differential is shot. There was at least a 1/2" of play.

Thanks for all the input!