Engine/Transmission (1998.5 - 2002) truck broke down! need advice! (long)

[JNeiman]

truck broke down! need advice! HELP!

Ok, my father was driving back from Michigan today in the 3500 in 6th gear with the Gear Vendor activated (70mph @ 1500rpm) while towing a 22' boat when he lost power to the wheels. As if the engine became disconnected from the rest of the driveline. He pulled over and stopped and then tried to take off again and it would move, but with loud grinding and thrashing noises. He had it towed to the nearest truck shop and it will be worked on tomorrow but I need some help diognosing what the problem is so I don't get burned by the repair shop 2-1/2 hours away. I went out to pick him up and get the boat and when I was there he had me play with it a little to see what I thought. Eased off the clutch in 1st in 2H and as soon as I was off the clutch it was thrashing and grinding, but it would move. When I tried 4L (4H is difficult to get into unless moving) I had no unusual noises or problems. I think the rules out the transmission as a problem because it went into all the gears fine and engaged fine. Now the question is what is bad.



A. )transfer case... I doubt it

B. )Gear Vendor... likely

C. )Rear end gears... possibly



Please help me out if you have any input. I need the truck back ASAP. I brought with me all the original parts to remove the GV including a stock driveshaft. I think we'll start with that. Thanks a lot guys... you're a huge help!

 

[HEMI®Dart]

Mikepvg has had trouble with his Gear Vendor trans too.



More info: https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=74437

 

[jlhartak]

Just read a recent thread with the same symptoms, the guy was towing and his truck started slowing down with grinding thrashing. It was the clutch disc, the center hub separated from the disc. I would check that before taking off the GV. pulling a load at that low RPM creates lots of vibrations and high torque through the clutch to the trans. Hope this helps

 

[JNeiman]

The clutch idea seems reasonable, but why wouldn't it do the same when in 4L? It worked perfect when I was moving it around in 4L. I am pretty convinced that it is either the Gear Vendor itself or the rear end. When I am in 4 wheel drive, not as much power would be going to the rear and it would also be pulling itself, reducing the thrashing. Does this sound possible? I think the right idea would be to have them throw the truck back together without the Gear vendor and see if that fixes it. Thoughts please!

 

[kaffine krazed]

First I would check how much movement there is in the driveshaft see if you can turn it by hand in neutral with the rear wheels on the ground.



Does the truck move at the correct speed for the RPMS? If not then I would have someone walk next to the truck to see if the driveshaft seems to be spinning faster than it should.



Does the GV go before or after the transfer case?



Does it make the noise in all speed of the GV?



Put it the truck in the air and see if you can hear where the noise is coming from.

 

[jlhartak]

Yes you did say 4L! That means the GV was essentially in neutral because the front end would pull the truck even if the rear driveshaft was removed. Try it in 4H, if the truck moves OK with no grind/thrash then I would say you have pretty much isolated the problem to the rear end or GV. Krazed has good ideas on the driveshaft, and finding the source of the noise. If the truck will move in 4H without grind/thrash I might consider removing the rear driveshat and driving it home on the front end. If you think it may be the rear end you can remove the axle shafts, then find a couple of tin cans the right dia. and push them over the end of the bearing hubs to keep the dirt out, you could attach hose clamps to keep them tight. My uncle used to do this on his old jeep when he towed it long distances. Don't forget the weird handling you will have putting all that torque only through the front end. Hope it goes well!

 

[JNeiman]

Woohooo... now we're getting somewhere. I agree that it is either the GV or rear end. BUT, I am not driving the truck home as it is... it is in a shop and its getting fixed there. I just want to be able to call them tomorrow @ 8am and tell them what to fix so they aren't trying to sell me on a new transmission and have my truck laid up far from home for nothing. I am 95% sure it is the GV, 1% on the transfer case, and 4% on the pinion or ring gear in the rear end. Let me know guys! Its IMPORTANT!

 

[rrowdy]

GV most likely culprit

I used to build these overdrive units for other applications.

They were actually Laycocks built in Sheffield England before GV

bought the licensing and started using them.



I'm sure GV made many design changes but they looked very close to the Laycock.



Inside is a sprag, clutch and planetary gear assembly. The planet gears probably failed and are causing the grinding noises.



It has always amazed me that GV put these OD's behind such

High torque applications as Motor homes and pickups etc.



Never heard anything bad about them but they just seemed so small to me, and they always run very very hot. The clutch is a double cone that gets worn if the line pressure is not high enough, Minimum was 575 PSI for the Volvo diesel application.



I have also done a few US gear OD's with failed planetaries

too so I think that is the most likely failure.



Hope this helps

 

[RustyJC]

Does your dad's truck have an exhaust brake? If so, had he been towing using the e-brake with the GearVendors OD engaged?



Rusty

 

[JNeiman]

It turns out that it is the transfer case. When the mechanic opened it up, it was bone dry. Its gonna cost between $1400 and $2400 to get it replaced:--) . I don't totally understand how this happened but I don't think they are lying about it because they have been making calls all day trying to locate one. If anyone in the Syracuse area knows where to pick one up, please let me know! Thanks, JOE

 

[JNeiman]

It turns out the transfer case had no fluid in it. So we are now searching for a new transfer case for a 3500 to mount behind the spd transmission. Not too easy to find. If anyone knows of any, please let me know! The truck is in Syarcuse NY right now. The closer the better. Thanks, JOE (518) 669-4426... and remember, check your fluids!!!!!!!!!!!!!!

 

[JNeiman]

The transfer case self-destructed. It had no fluid in it and thats what caused all the trouble. We are trying to locate a new or used transfer case ASAP. If anyone knows of any that would fit behind a six speed please let me know! The truck is in Syracuse NY, so the closer the better! Thanks, and check your fluids!