I have exhausted my ideas, and still have not come up with a solution.
Here is the problem. I recently completed a 3.4l swap into my 86 4runner. I am using an R-150 into an inchworm adaptr into marlin MC05 dual cases. I have a toyota CV in the rear shaft. The problem I have is that I get a drone at speeds of 55 mph and 65 mph. The drone is heard under acceleration and deceleration, but not while coasting. The trans is rebuilt, and this noise did not occour when I ran the same trans and t-case setup with the 4 cyl. I have a budbuilt crossmember with two mounts. The engine mounts are in good shape
What I have done.
I have checked to make sure that the drivetrain is not contacting th body at all.
Tried 3 different drive shafts. The most current one balanced to 3000 rpm This seemed to make the noise less noticable.
I have shimmed my axle to try many different pinion angles and have settled on about 1 deg down. This did not have any effect.
I have changed my differential.
I have completely dissasembled my t-case, inspected the internals and changed the output shaft bearings.
I have tried different tires.
Here is the interesting thing.
The noise is worst when the truck is empty, however if you roll down the rear window, it is almost not noticable.
When loaded with camping gear the noise is less noticable.
When towing a trailer the noise is the least evident.
When driving at speed with the tires aired down the noise is the loudest.
I have come to decide that the noise is some sort of harmonic in the body, but it still drives me crazy. I just wanted to bounce this off of you guys to see what we could come up with.
Thanks in advance.
Nathan
