77RogueRunner

Been driving my 88 Runner around recently with the 3.4 mated to the R150F r/h drop tranny and some weird stuff is happening. Used a new t/o bearing for the year tranny (95), kept the 3.4 clutch and related stuff, used pilot tool, etc. Weird thing is that it get some nasty vibrations when starting in first, accelerating and shiffting to second and accelerating. They diminish the faster I'm going. After I get up to 3rd and up to speed (50+miles per hour)the vibrations are almost un-noticeable. I remember when I was doing this swap I had to let air out of the tires(firestone M/t) for the body lift cause I was limited to the height of my work area. Could my tires sitting at 20-psi for a few weeks with the weight create a flat spot? I drove it about 20 miles round trip and they vibes were still there when I came back and slowed down. The only other thing I can think is I got a bad tranny. If I'm going down a hill and I let off the gas just enough to feel like I coasting, a blarring, kinda rotating scrapping sound is heard, alternately if I'm going say 50 on a flat surface and push the clutch in to coast, I hear the same noise. Anybody have an idea what this might be? I'm gonna take the inspection cover off but I can't really see past the plate. The vibrations are consistent with the speed, not engine rpms. Would there be something in the tranny or t-case that as it speeds up (output shaft?) would kinda align itself from the centrifugal forces? The tranny was a dune rollover so I'm hoping a driveline didn't get smashed or jammed in the process. Thanks...D

iamsuperbleeder

did you use your original drive shaft and u-joints?

almost sounds like a u-join vibration

77RogueRunner

Yes I used the originals. I got underneath there and grabbed and tried to wiggle the rear shaft around, it seemed tight up and down, back and forth. I did use a Longfield 1.5" aluminum driveshaft spacer on the diff side to put the shaft(s) spacing where it was originally, I can't see this being the problem as it appears to be lathed/machined, and of course the quality of the name. I'd think something in the shaft would just get a worse vibration with higher speeds? There was a little slop in the diff side joint, but i don't think it is enough to warrant the vibrations. However now that you mention it I should probably replace those anyway with some beefier ones. Pulled the cover and the plate was good and tight. Hate to pull the tranny now with those tight spaces...

77RogueRunner

It's all good. I got the vibrations to stop. I got a new (used) off the shelf tranny/t-case from Peach Street Recycling in Grants Pass (I highly recommend them for anybody in the S. Oregon area), new u-joints, did some reading up on "driveline phase", and got my rear diff rebuilt by a very savy mechanic known as "Gnob" on some other forums. Kinda glad I got the tranny combo despite everything else. When I pulled the old combo and drained the t-case fluid it looked like half and half.