Engine/Transmission (1994 - 1998) Drive shaft

[SRehberg]

Those of you that have a Gear Vendors OD or maybe even U. S. Gear, do you still have the two piece drive shaft set up or now a one piece? I've got a '96 extended cab long bed so I'm looking for comparable trucks. I develop more vibration than I think should be there at 50 mph. I've had a new drive shaft/U joints installed so I was thinking just due to the length of the one piece it might be an issue. Thanks

 

[muchsnow]

(Bump) Gear Vendors unit GearVendors

Those of you that have a Gear Vendors OD or maybe even U. S. Gear, do you still have the two piece drive shaft set up or now a one piece? I've got a '96 extended cab long bed so I'm looking for comparable trucks. I develop more vibration than I think should be there at 50 mph. I've had a new drive shaft/U joints installed so I was thinking just due to the length of the one piece it might be an issue. Thanks

I have the same problem with mine, the output shaft also eats the inboard splines on the yoke over time and requires periodic tightening and replacement of the yoke. Vibe is right around 50 mph then you engage the unit and it is significantly reduced.

I don't get it, the angles are good... ... ...

You ever figure yours out??<!-- google_ad_section_end --><!-- google_ad_section_end --><!-- / message --><!-- sig -->

 

[Missouri Mule]

Usually you get a better ride with a one piece drive shaft. If it was the drive shaft causing the problems you would get a vibration at all speeds. Mite be u-joints.

I make sure your trans mounts are OK. I don't know if the overdrive units have mounts if they do check them out. It mite be the over drive unit itself or how it bolted to trans.

 

[Loren]

SRehberg,



Are your u-joints in phase? This might be the cause of your vibration. It might also be the cause of muchsnow's spline problem.



U-joints are in phase when the yokes on opposite ends of the shaft (as opposed to the yokes on the differential and transmission) are both going the same direction. That is, if one is vertical, the yoke at the other end of the shaft is also vertical.



If u-joints are out of phase, the output rotational speed will vary even though the input speed is constant. This causes problems.



To answer your question about two-piece driveshafts: My 2000 Quad-Cab, short-bed truck had a one-piece driveshaft when it came from the factory. I kept the one-piece driveshaft after I installed my U. S. Gear overdrive.



Originally, I did have some vibration problems -- to the extent that the cruise control would not stay engaged on a rough road. I cured the issue by fabricating a rubber mount for the U. S. Gear overdrive transmission. I surmised that the additional weight hanging, unsupported, behind the transmission wasn't good. Apparently I was right, the problem was solved.



Good luck with your installation. I considered the overdrive to be about the best accessory I ever installed on that truck (and there were LOTS of accessories). I still have the overdrive, with the hope that it will fit my new 2008.

 

[muchsnow]

SRehberg,



Are your u-joints in phase? This might be the cause of your vibration. It might also be the cause of muchsnow's spline problem.



U-joints are in phase when the yokes on opposite ends of the shaft (as opposed to the yokes on the differential and transmission) are both going the same direction. That is, if one is vertical, the yoke at the other end of the shaft is also vertical.



If u-joints are out of phase, the output rotational speed will vary even though the input speed is constant. This causes problems.



To answer your question about two-piece driveshafts: My 2000 Quad-Cab, short-bed truck had a one-piece driveshaft when it came from the factory. I kept the one-piece driveshaft after I installed my U. S. Gear overdrive.



Originally, I did have some vibration problems -- to the extent that the cruise control would not stay engaged on a rough road. I cured the issue by fabricating a rubber mount for the U. S. Gear overdrive transmission. I surmised that the additional weight hanging, unsupported, behind the transmission wasn't good. Apparently I was right, the problem was solved.



Good luck with your installation. I considered the overdrive to be about the best accessory I ever installed on that truck (and there were LOTS of accessories). I still have the overdrive, with the hope that it will fit my new 2008.

phasing is good, I've always wondered about having the smaller u-joint on the front though. Larger diameter shaft really seemed to narrow the range the vib occured. I'd really like to know what mount configuration you came up with though, because I think that great big chunk of aluminum hanging off my transfer case has alot to do with it. It has swing to it even w/new trans mount.

Thanx... ... ... ... .

 

[SRehberg]

I have a large diameter driveshaft as well, U-joints in phase. It's a brand new drive shaft which didn't cure the problem. I'm beginning to wonder if you haven't hit on the cure as my GV OD unit hangs on the back of the transfer case which is hung on the transmission. BIG LEVER action. The problem however seems to be there loaded or unloaded but worse loaded. Trans mounts are tight, not broken and the yoke at the GV unit is tight (150 lbs/ft. ) I know the driveshaft is at max recommended length (5 ft) for this lash up according to GV.



Loren, can you post a picture or give details about the mount you fabricated? It might just do the trick.

 

[Loren]

No photos, sorry. I don't have a digital camera (and refuse to learn how to use my wife's). Also that truck is now somewhat in pieces. I wrecked it almost a year ago and have been salvaging accessories from it since then.



The mount was basically a jury-rig deal, but it didn't look too bad and worked well. Here's how I did it.



First off, I had to have my fuel tank shortened to clear the new overdrive. The guy who did the work cut about a foot off the front and plastic-welded a one-inch thick piece of plastic at the front end of the tank. This thick plastic was right at one of the frame crossmembers that is bolted on. I had to remove that crossmember and add 3/4" spacers to lower it enough to clear the plastic. I sure hope that neither of you guys have this problem.



With my U. S. Gear overdrive mounted to the transmission and the transfer case mounted behind it, it worked out that one of the overdrive's flanges was in line with a frame crossmember. The flange was a place on the overdrive where there is a circle of bolts (or nuts on studs) holding the unit together.



I reasoned that if I could somehow connect something from the flange to the frame crossmember, I'd have a support. Looking at the other supports, I saw that they are all rubber mounted.



I went to McMaster-Carr's web site (here:McMaster-Carr) and searched for a mount that might work. If you search their site for this part number it will lead you to the right page: 9376K69



I got a piece of angle iron that had the right leg dimensions to reach where I needed it. I had to grind away part of one side to clear the overdrive unit, as well as a bit more to clear the overdrive oil drain plug. I drilled two holes to allow it to mount to the overdrive studs. This left me with a horizontal part of the angle iron directly above the frame crossmember.



I measured the dimension from the angle iron bracket to the frame crossmember and chose a rubber-mount from those in McMaster-Carr's catalog that would reach. I wanted it to be a little longer than the exact dimension with the hope that it might support the overdrive better.



The mounts I got had female metal threads on each end, so I bought the appropriate bolts and drilled the required holes in the frame crossmember and in the angle iron. This allowed me to support the overdrive unit with the frame crossmember while still using a flexible, rubber mount.



As I said, it worked. I never had any more vibration or cruise control problems after that.



If any of this is unclear, let me know and I'll try to clarify it.



Good luck,

Loren

 

[hsmith]

I have run the GV for a lot of miles with no vibration at all. I stayed with the two piece, just shortened the front section. But then, mine is 2wd.

 

[muchsnow]

I have run the GV for a lot of miles with no vibration at all. I stayed with the two piece, just shortened the front section. But then, mine is 2wd.

I'm thinking of going this route, GV has a plate (now they do... ... . wonder why?... ) that relocates the carrier further back. I've ordered and received it, pretty stout item (should have come with or been provided when I got the unit in 2001) now the trick is funding and a driveline shop that will do the best thing for it to work out properly... .....

I really wish the GV adapter/unit had come with built in provision for an add on mounting configuration... .

 

[SRehberg]

Loren, thanks for the description of the U. S. Gear mount you fabricated. It sounds like the U. S. Gear unit mounts differently, i. e. between the trans and transfer case vs. the Gear Vendor's mounts aft of the transfer case. I really hate to screw with the fuel tank so I will crawl under the truck and see what type of mount could be used.



Muchsnow, I'm not familiar with this new plate you mentioned, where does it mount? Does it bolt to the GV unit or the transfer case reaching back to the cross member? They must have realized it was a lot hanging on the trans as you said.



Hsmith, Perhaps with the GV unit mounted directly to the trans, the distance to the support is closer giving a stronger mount. With the two piece shaft it would be minimal distortion. I know with my one piece shaft, at 60", then throw in the GV unit, then the transfer case then the small distance to the trans mount, it becomes a pretty long distance. Apply torque and I'm sure something twists out of centerline.



Thanks

 

[muchsnow]

Loren, thanks for the description of the U. S. Gear mount you fabricated. It sounds like the U. S. Gear unit mounts differently, i. e. between the trans and transfer case vs. the Gear Vendor's mounts aft of the transfer case. I really hate to screw with the fuel tank so I will crawl under the truck and see what type of mount could be used.



Muchsnow, I'm not familiar with this new plate you mentioned, where does it mount? Does it bolt to the GV unit or the transfer case reaching back to the cross member? They must have realized it was a lot hanging on the trans as you said.



Hsmith, Perhaps with the GV unit mounted directly to the trans, the distance to the support is closer giving a stronger mount. With the two piece shaft it would be minimal distortion. I know with my one piece shaft, at 60", then throw in the GV unit, then the transfer case then the small distance to the trans mount, it becomes a pretty long distance. Apply torque and I'm sure something twists out of centerline.



Thanks

The plate mounts to the original carrier bearing holes and has holes to mount the carrier bearing further back.

 

[SRehberg]

I am interested in the setup you have as I wanted to go back to a two piece shaft and if I keep the GV unit (yes I've thought about ripping it out) the two piece with the carrier would work better. If it (the new plate) relocates the carrier rearward, is the angle still acceptable?



The way my setup is now, it's a long way between the trans mounts and the rearend.

 

[muchsnow]

gear vendors vibration

I am interested in the setup you have as I wanted to go back to a two piece shaft and if I keep the GV unit (yes I've thought about ripping it out) the two piece with the carrier would work better. If it (the new plate) relocates the carrier rearward, is the angle still acceptable?

The way my setup is now, it's a long way between the trans mounts and the rearend.

We'll see eventually, the driveline shop I talked to about it says it can be done, but thought it would also be a good idea to find a way to secure that long mess aft of the xfer case.

They said they had seen many shake due to the length and not all the time.
Something would trigger it.

 

[SRehberg]

I contacted GV where I was told I either had a drive shaft balance problem or driveline angle issues. With two different driveshafts I doubt they both had balance issues at the same speed. Now driveline angle I don't know but I sure lean towards the length of the driveline behind the transfer case as the primary cause. It seems to be worse with heavy loading so I imagine the trans mounts are taking a heck of a strain perhaps distorting throwing off angles. Frustrating.

 

[Curious Dave]

Guys... I had a GV on for awhile... Until I broke it. #@$%! They tried to sell me a new one saying that they will hold up to the Cummins. I told the guy apparently they won't. I had it rebuilt and am going to use it in my car. Anyway... .

The extra weight hanging off the transfer case along with the extra length of the single shaft are both factors to be addressed. I would put in a crossmember for the GV and see if you could use the 2 piece shaft with the carrier bearing. I suggest this because it is what I was going to do. I didn't because the darn GV left me stranded in the middle of a freeway in Penn. It cost me $1500 to get back up and going with just taking the darn thing off. I was towing my 37' Everest when the GV broke. However, I enjoyed the GV while I was in Montana with no peed limit.

 

[T. Vann]

Driveshaft

I have a 96 Dodge extended cab 4x4. I have over 100,000 miles on a Gear Vender unit with 90,000 of those miles with a single driveshaft. There is no doubt in my mind you need to eliminate the short driveshaft and go with one long one. That eliminated any vibration I had and I haven't had any trouble since.

T. Vann

 

[hsmith]

Maybe so on a 4X4, but on a 2wd a one piece shaft would be one loooooong sucker.

 

[muchsnow]

Long..

Maybe so on a 4X4, but on a 2wd a one piece shaft would be one loooooong sucker.

It's a long one on a long bed extended cab 4wd also... ... .

 

[SRehberg]

It doesn't make sense to go to a long shaft rather than a two piece that is supported in the middle. GV even admits I'm at the ragged edge for a one piece shaft (60"?) so with the unsupported GV unit it seems I'm asking for trouble. My preferred solution is to remove the GV unit and go bone stock again. I need to find the two piece shaft w/carrier and I'll be good to go. I know these units have their place but so far I have been less than impressed.

 

[hsmith]

And your definition of "less than impressed" is? I use the GV and have gone thru a couple myself.