Driveshaft U-Joint & NVG4500HD?

[KEENO]

Hello First Gen Gang!



My truck has been 'eating' lower rear U-Joints at the rate of (1) every six months. It's always the one at the Diff only!



I haven't been able to figure out why this is happening over the past 1 1/2 years. No change in the rear driveline over OEM..... Except the addition of a NVG4500HD Trans Summer of 2001.



Question: Is the NVG longer than the old Getrag possibly creating a minute change in driveshaft angle?



Any NVG Conversion folks having a similar problem? I'm grasping here I realize!



Any help or opinions would be appreciated.....



Tim "KEENO" Keen

 

[BushWakr - RIP]

Hey Keeno !!!! GTSU bud... .....



Is it possible that you have had some axle wrap that has moved the axle tube into a critical angle??

Is the pinion shaft (?) sloppy and causing "progressive damage" to the universal?? Is it securely fastened??

Any sign of balance weight loss on the driveshaft??



Just some thoughts... . HEY GUYS, IDEAS ~~~!!!!!!!!!!



Bob.

 

[KEENO]

Thanks for the ideas Bush!



The Dana 70 was rebuilt by Quad 4x4 in MT. when the trans was converted. I would think it's in good shape but I haven't checked anything besides giving it a 'wiggle' (pinion shaft) when I replaced the U-joint yesterday.



I've even tried Neapco U-joints last time over the Spicer..... same life expectancy (approx. 15,000) w/ regular greasing.



The truck has the 2 1/2" Skyjacker Springs in the front but the rear is OEM. The front springs should have no effect on the rear driveline angles. The only variable is the NVG in the rear.



If it was my driving style..... Why am I eating lower U-joints 3:1 over the one near the Transfer/Trans???



Maybe a visit to a driveline shop might be in order next U-joint.



KEENO

 

[JLEONARD]

Keeno,

1st thing to check is driveshaft balance.

Is the NV transmission longer than the old one? This would make a higher U-joint angle. which equates to more load. A minute change is no big deal... . can you measure the angle and let us know what it is? Perhaps someone with a stock transmission can do the same and we can compare. I can give a subjective judgement of the effect of the difference..... I work with steering u-joints every day and the principles are the same.

I can assume that you are being careful to install the u-joints... at least after the first early failure... ... as in the joints are centered in the housings. Sorry had to mention this.

Did the driveshaft get shortened? If so, there are some things that should have been considered, such as orientation.

As the u-joint rotates the angular velocity changes and must be "balanced" in order to cancel out. Orientation of the u-joints are the big factor.

Just asking the perhaps obvious.

Can you put an indicator on the driveshaft and see if it runs out as it rotates? An easy test that might tell us something.

Sorry for the ramblings...

Jay

 

[RDBuck]

NV4500

I installed my NV4500 myself and never liked how the square "tubing" used for the rear mount mated to the crossmember. It did not sit flat on the crossmember but at a slight angle causing the flat bar to which it bolted to twist and compress the rubber mounts unevenly. It bothered me enough that I ran with it about 2 months and then took it back apart to inspect. Sure enough the square 3" mount was cracked across its' entire length. I made a new mount out of heavier stock and welded an angled shim on the bottom to make it sit flat and also improved the attitude of the rear of the transmission. Have not had any universal problems and cannot say that this has anything to do with your installation but pass the info along for what it is worth.

 

[JLEONARD]

Keeno,

One more thought ... ...

With the driveshaft connected , if you remove the bolts that mount the center support bearing, does the bearing stay in position or does it shift? Just wondering if the bearing is in the right place or is side loading the driveshaft.

Jay

 

[KEENO]

Thanks for the replies.....



JLEONARD: It looks like I have some homework to complete! I appreciate the advice & tips. Maybe I need to pull the driveshaft once again and have it checked for balance by a shop. I'm not getting any unusual vibration in the truck though. BTW: My truck is a std. cab and doesn't have a Carrier Bearing Assembly, so this eliminates one more variable. Thanks again... . I need to do some further investigation.



RDBUCK: Great thought on the trans mount & crossmember. My NVG Conversion was done by Quad 4x4 and uses a very robust, fully welded trans support. Your description sounds like the 'not so robust' design that comes in the Advance Adapters NVG kit. The Quad 4x4 mount is substancially different & stronger. Great thought though... . I wish it was as easy to Root Cause it to the support.



It looks like a trip to the driveshaft shop in the near future. I wanted a different yoke placed on the front driveshaft (4x4) after the 2 1/2" lift to keep the caps from making contact w/ the yoke. Maybe I'll just drop the complete truck off!



KEENO

 

[JLEONARD]

My truck is a std. cab and doesn't have a Carrier Bearing Assembly,

2nd time I saw this recently...

I have a standard cab 2 wd with a carrier bearing...

Hmmmmm... more Chrysler cost savings

Jay

 

[Paychk]

I think the difference may be 4x4 compared to a 4x2?

 

[KEENO]

No, It's an Extended Cab Vs Standard Cab Deal.....



My (3) Extended Cab - First Gen Driven W250 (4x4) Buddies all have the Carried Bearing Assy (or Mid Ship Bearing assy or Support Bearing) on there trucks.



The other STD. Cab First Gen that I used to spend time in..... Has no Carrier Bearing Assy.



I think it's a length issue due to dynamic balance..... JMO.



Thanks for all of the help... ...



KEENO

 

[RDBuck]

Front yoke

You are correct,my NV4500 was an Advance Adapter unit and the transmission to cross-member mount is junk. You mentioned your front end yoke and that reminded me that I sheared mine off(due to running around for about a month on front drive only when my rear end was making bad noises-had the rear drive shaft removed) and when I got a replacement from Dodge it had been upgraded. The new unit is more substantial and comes with a new cross member for the universal as it used two different size bearing caps. Might want to look into this. When I put the 2" skyjacker springs in my truck I ground some material off the CV joint next to the transfer case. I also had my front drive shaft lengthened about 1".

 

[BushWakr - RIP]

I don't have anything new to add at this time however...



Keeno is one of the old (original) gang in here and doesn't often ask for help, so , keep the ideas coming lets try to help solve this, for all our sakes if nothing else...



bob.

 

[Paychk]

Just to add confusion to the carrier bearing waters, mine is a standard cab 4x2 and it has the bearing. I wonder why the difference?

 

[dpuckett]

Originally posted by Paychk

Just to add confusion to the carrier bearing waters, mine is a standard cab 4x2 and it has the bearing. I wonder why the difference?

Paychk- it is due to the fact that we 2wd guys have no t-case, and thus a single shaft would bee way too long. The shaft in my W250 RC was around 4' I think.

ANyway, I had a problem similar to Keeno's last summer, and the stock shaft was warped to the tune of about . 040- . 060 in. runout. Had a new one built- 4"- and had no problems after that. Get the shaft checked, and check the yoke itself for wear. The u-joint should pop in with a considerable effort and lining it up just right, required. If it just slides in, you need a new yoke. WIth my warped shaft, I went through a yoke in about 10K miles, and u joints were lasting 5-6K. Good luck, and report back to us.



Daniel Puckett