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gcgreenwood · 11-17-2008, 06:07 PM

Well, here we go again. Found the bell housing on the tranny cracked. Took it to my favorite truck repair to have it removed. Then took it to a rebuilder who took my insides and put them in a used case. Also replace the worn parts. The truck repair inspected the drive shafts, balance them and replaced the worn U joints. Put it all back together. Tranny works great. Now the problem. There is vibration in the drive train. Took it back to truck repair and they went through it again. Their diagnosis is the angles of the drive train are outside the norm and I'm getting sine wave vibration because of it.

Anyone else having this problem? If so, is there a fix? 45-53 it's there and then goes away.

The truck repair said the reason I didn't notice it before was the worn U joints were absorbing it. The rebuilder said the only time he had seen a cracked bell housing was if the drive train was out of balance. So it all seems to fit. When you look at the drive train from the tranny it goes down to the first carrier bearing then up to next carrier bearing then down to the rearend. Also the engine tranny tips foreward so the tranny is higher in the back, not down.

Thanks
Gary Greenwood
Leslie, MI

Mike Leary · 11-17-2008, 06:28 PM

Check the alignment of the air bags and the motor mounts. A cracked housing is rare & makes me wonder
if other problems exist; do you have a aftermarket overdrive?

bkahler · 11-17-2008, 07:14 PM

Gary,

Check out this thread http://www.airforums.com/forums/f159...ons-38354.html there is a lot of good information on diagnosing drive line vibrations.

Personally I don't buy the explanation about the worn u-joints absorbing the vibration. Sounds like an excuse to me.

Let us know what ends up fixing the problem.

Brad

Mike Leary · 11-17-2008, 07:22 PM

Quote:

Originally Posted by bkahler

Personally I don't buy the explanation about the worn u-joints absorbing the vibration. Sounds like an excuse to me

Ditto, it never entered my mind unless drive train work was done or o.d. was installed. Those u-joints, if serviced, last and last. Check my mileage: I have the originals.

jking · 12-20-2008, 02:28 PM

Gary, we once had a 1982 with the Isuzu diesel that had a crack in the tranny case. A/S even made a special hoop-skirt-looking thing to fit into the open bottom of the engine/tranny junction that was supposed to solve the problem. It didn't. The "flex plate" that joins the engine drive shaft to the tranny input shaft must - emphasize must - be super-carefully balanced with welded-on weights to remove the unbalance vibration that stresses the tranny case and causes cracks. Best of luck and keep us posted. Jamie

ram64gq · 12-24-2008, 06:20 PM

Hi,
I just bought a 28' 1982 airstream with an isuzu 6BD1 turbo diesel. Anything you guys could recommend. It is still in Oregon and probably drive it here to Anchorage Alaska next May 09. I am having a sway when driving at 60MPH. I guess probably it is the steering damper. I would appreciate any suggestions on engine, transmission and auxillaries- ram64gq

Mike Leary · 12-25-2008, 11:56 AM

After you check the tires and shocks & damper, you'll prolly find the front end needs a alignment. Be prepared to replace both bell cranks. Camping World has some cool ones. Have them check the wheel bearings, too.

Mike Leary · 12-25-2008, 06:32 PM

I was not suggesting you have Camping World do the work; a heavy truck spring shop is where you want to go. We had our's aligned at a Peterbuilt outlet after the front coil springs were replaced. As I recall, the left steering bell crank can be replaced without re-alignment, but I could be completely backwards, which is happening a lot lately.

ram64gq · 12-26-2008, 02:28 PM

Hi,
Thanks Mike
Ray

Mike Leary · 12-26-2008, 03:25 PM

Quote:

Originally Posted by ram64gq

Hi,
Thanks Mike
Ray

I'll be back in the Seattle area in the spring; glad to have a look at the old dear for you. Send me a PM and
I'll give you my cell #.

mcplaidpiper · 01-12-2009, 08:29 AM

Hello:
My 1982 AS is in the shop and they found I need a new 'harmonic balancer'; and to make it worse, they are not able to find a local source/supplier. Does anyone on the forum know a source, or offer a recommendation for a supplier for a harmonic balancer for my 6B1D1 diesel? Your quick help/advice would be appreciated. I am in the Dallas/Fort Worth Texas area.
Thanks!
Dale

Mike Leary · 01-12-2009, 10:00 AM

Try a GM truck dealer, that's a P-30 chassis, I don't think you'll have a problem.

mcplaidpiper · 01-12-2009, 11:36 AM

Thanks Mike for the reply.

The workshop advised me they called the local chevy truck dealer who sent him to an Isuzu dealer, who referred him back to the Chevy dealer....

Mike Leary · 01-12-2009, 12:17 PM

Try Tom's Truck....1.888.661.6502 or MER Equipment...1.800.777.0714. www.merequipment.com
I'm sure a few of us would like to know how the balancer got trashed.

mcplaidpiper · 01-12-2009, 09:45 PM

Well, I bought this MH from the original owner (80+ yo) which had sitting in a field for a couple years...only has 38K miles. But it was just about beyond bring back to life, but thought I'd try. The diesel mechanic was driving it on the 'final' and found the Harmonic Balancer needed replacing. I was told that this is attached by a rubber part that is pressed into the balancer and flywheel (I think he said) and the rubber part will eventually become rotten and come loose/off. That's what I'm being told anyway...your thought??

I hope I can find a new Harm. balancer here in the Dallas area...or someone who can realiably rebuild it. I've never heard of one of these going bad...

bkahler · 01-12-2009, 10:12 PM

Yep they do go bad. Sometimes the outer pulley part will just slip a little due to rotted rubber and then your timing marks don't line up. I'd say your mechanic is telling it like it is and you need a new harmonic balancer.

You might try some salvage yards that cater to box delivery trucks. There are bound to be some in the DFW area.

Good luck!

Brad

mcplaidpiper · 01-13-2009, 06:29 AM

Hey Brad, thanks for the reply. I'll call around to some of the wrecking yards in the DFW area.

While they are in there I'm going to have the chassis air conditioner repaired/replaced (unless it's just way too much $$$). The current (hopefully OEM) compressor has no visible markings-per the mechanic. Do you/anyone have an idea the make and/or model of compressor used on the 1981/1982 Isuzu's? I haven't found this info in any of the documents that came with the MH. I expected it would need replacing, so I'm not sure why the old make/model info would be needed?
Thanks!
Dale