Drive Shaft U-Joint Fail

[Dave Kay]

Of the many older GM civi-trucks I've nursed back to health over the years all seemed to have drivetrain vibrations of some kind or another. So I've always made it a point to at least replace u-joints asap and look around for bad engine/trans mounts, etc., that's where the culprit usually hides.

And it's understood, sometimes we all overlook a critical maintainance task. But I think the point that everybody was trying to impress is--- when it comes to these GL-handled rigs--- prompt drivetrain work & inspection is absolutely mandatory!

Meanwhile... when will it ever end... CURSE those wicked GL-forklift butchers!

(a wicked forklift butcher getting their due!)

 

[stampy]

Same thing happende to me. I lost a driveshaft on the way to a recovery. I had replaced the u-joints with the high dollar greasable ones too. I had driven the truck for months after that. Then on the highway bam! I found the driveshaft about 2000 feet behind me after looking it over I determined there was unseen metal fatigue on the ear. Luckily Neil hendrix was there and we found a junkyard with a civi driveshaft and thats what I am currently driving on. The only issue I may have now is axle wrap. Anyone else feel like (when stopping fast ) that the rear springs flex. I hear a noticable "bump". I guess replacement springs would fix this?

 

[QuickSilver]

Did you snag that 1009 in spearfish or here in town?

In Spearfish. Integrity Ford had it sitting in the back lot. I guess it originally came from that slew of them that went through Goodrich.

 

[Hasdrubal]

When I first got my M1009 7 years ago, we put a 4" lift in it. 2 years later I started hearing a high pitched squeeling underneath. It was the original u-joint near the transfer case, the bearings were dry and grinding into dust. Put new greasable u-joints in. They only lasted 3 years, same symptoms. Unforgiveably!... I had never re-greased them. Now I grease them heavily every once in a while. Seems with the lift and the subsequent angle imposed on the forward u-joint the load is increased, as the rear always looked fine but replaced them as a pair anyways.

 

[QuickSilver]

Yep, cheap insurance. I think after this ordeal I'm going to just replace all of them. I have been going through everything since I got it a couple weeks ago. Unfortunately, I hadn't gotten that far yet. Darn!

 

[kipman]

The rear u-joint on my 1009 was making a squeak, took out the drive shaft, the u-joints were original from GM, they failed at 177000 miles, pretty good part, they were sealed joints, only one cap was shot.

 

[jdemaris]

I'm finding out now as I call around looking for a case that this is a very common problem.

Yes, it IS a very common problem. Some K5 Blazers can barely get 8K miles out of that rear joint. Sometimes, it can let loose and cause the transfercase to blow to pieces, with NO prior warning or vibration. I lost one that way. Going down the highway at 70 MPH. Driveshaft came unhooked, spun around, tore off my exhaust system, parking brake cable, and then jammed against the road and split the aluminum transfercase.

K5 Blazer has a pretty severe angle at that joint due to the short wheel base. And, many K5s get out-or-round pinion flanges. That seems to be the main cause of premature rear U-joint failure. Just out of round enough so the caps on that U-joint do not get clamped with even force all the way around. Then those two caps burn up pretty fast, while the other two in the driveshaft itself are often fine.

If you have Blazer with the short-life problem, buy a new pinion flange. I would not of believed it until I fixed two problem Blazers that way. Also, you can drop the transfercase down by changing the location of two bushings on the crossmember that holds it. That smooths out the driveshaft angle a bit - but you also lose some ground clearance that way.

 

[CUCV85]

Replace all your u-joints as you can

When I first got my M1009 7 years ago, we put a 4" lift in it. 2 years later I started hearing a high pitched squeeling underneath. It was the original u-joint near the transfer case, the bearings were dry and grinding into dust. Put new greasable u-joints in. They only lasted 3 years, same symptoms. Unforgiveably!... I had never re-greased them. Now I grease them heavily every once in a while. Seems with the lift and the subsequent angle imposed on the forward u-joint the load is increased, as the rear always looked fine but replaced them as a pair anyways.

I replaced the rear drive shaft u-joints shortly after buying it as preventive maintenance. I used the ones from Advance Auto Parts that have both a Zerk and a needle greaser Zerk on one of the caps. Sometimes, well most of the time it's a pain to get to the regular Zerk in the center of the u-joint. So having bought a needle greaser adapter it is so much easier to grease u-joints. I purchased the 3 for the front shaft at the same time, have them under my seat and will install this spring. I have installed a 4 inch lift and notice a little vibration that is bugging me. BEST THING TO DO WHEN YOU GET YOUR VEHICLE IS TO REPLACE THEM ALL ASAP. I will also inspect the front axle u-joints this spring and may replace them and put in new wheel bearings. I already repacked the original wheel bearings what a pain! They where both all dried up!

 

[QuickSilver]

Well, I have a case for the TH400 on the way from a guy in CA, so hopefully the 09 will be back on the road sometime this upcoming week.

 

[ssgtcampbell77]

Just in case you need it. Rebuilt for $700

Freshly Rebuilt BOP TH400 Automatic Transmission on eBay!

 

[QuickSilver]

Just in case you need it. Rebuilt for $700

Freshly Rebuilt BOP TH400 Automatic Transmission on eBay!

Thanks for the heads up.

 

[jdemaris]

Just in case you need it. Rebuilt for $700

Freshly Rebuilt BOP TH400 Automatic Transmission on eBay!

That won't work. It's a gas-engine trans, AND it only fits the Buick-Olds-Pontiac engine bolt pattern. 6.2 diesel uses a Chevy bolt pattern.

 

[QuickSilver]

That won't work. It's a gas-engine trans, AND it only fits the Buick-Olds-Pontiac engine bolt pattern. 6.2 diesel uses a Chevy bolt pattern.

Ok, I understand the bolt pattern issue, but is there any difference between a TH400 for gas vs. for diesel? I thought they were the same.

 

[ssgtcampbell77]

I didnt know there was a difference. My bad.

 

[jdemaris]

Ok, I understand the bolt pattern issue, but is there any difference between a TH400 for gas vs. for diesel? I thought they were the same.

Diesel trans is setup differently. Uses a special low-stall speed torque-converter and a different governor. Probably a few other minor differences I don't recall at the moment. I just got done swapping a gas 700R4 over to diesel specs and it had even more differences.

Regardless. that doesn't mean you can't bolt in a Chevy TH400 from a gas engine and use it on the 6.2. It will just run differently that it's supposed to. Especially the shift RPMs.

I've got a gas-engine TH400 in my 83 diesel Blazer. It origijnally had the 700R4. I stuck in the gas TH400, along with a diesel torque converter and a mechanical modulator. It shifts at higher RPMs than it ought to, but otherwise it's been fine. It's my best snow plow truck. I also had to swap in a different transfercase to make the TH400 fit. It uses different splines then the 700R4

If you really get stuck finding one, I've got a good TH400 and torque converter out of an 89 diesel Suburban (4WD).

 

[QuickSilver]

Ok, thanks for the info.

 

[QuickSilver]

Well, I bought a new trans case off of ebay, then hauled it and the busted one down to our local trans shop. Took about a little over a week for them to get mine in. The guy that did the work said the innards looked almost like new. He replaced a couple of clutch disks since he was in there anyway, and that was it. I'm putting it back in today. Hopefully all goes well.

 

[RoboGaJr]

Anyone had a problem with the rear u-joints being different size's? Does the M1009 use the same as the Civi models?

 

[Cucvnut]

yes.

 

[stampy]

Yes civi driveshafts can be used. I have a civi rear driveshaft in mine for over 2years.