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73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Transfer Cases and Front Drivelines => Topic started by: Psycho71 on December 04, 2010, 10:37:37 pm
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Bought a 3/4 4x4 burb a while back. '85 model with a 350/400 208 drive train. Got the engine built, trans dropped off to be built, and today I broke into the transfer case to inspect it and replace the seals. Mechanically it looks fine. The seals are dry and hard, so I am glad I chose to look it over. I have the necessary seal kit, so they are all getting replaced. Just a question or two about this thing before I put it back together.
I can cycle the shift selector, turn the shafts by hand, and get it to engage into 2hi, neutral, and 4low. But it doesn't seem to be engaging in 4hi for some reason. 4hi acts just like 2hi does (1:1 ratio), but doesn't engage and turn the chain/front shaft. Is there something in the way this thing operates that will not allow this to happen on the bench? 4low gives me both shafts turning together at the lower 2.6:1 ratio, just like it should. All of the gears inside look good, no abnormal/excessive wear present.
Also, how much slack is acceptable in the chain. With the case split apart and the two main shafts not supported on each end, it seems like there's not much slack present. I can push the ends of the two shafts apart slightly and all the slack goes away. I'm assuming I need to check the slack thru the top fill hole when i get the case put back together?
I did notice "japan" on some of the bearings inside. Any concern with japanese bearings? I know Timken are usually best, right? The bearings are all in fine shape and tight. Should I just run it with the Jap bearings or spring for some USA made stuff?
Thanks for any advice y'all can offer. This is my first endeavor into the 4x4 world, and just want it all to be right before I put it back together.
Jay
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I wouldn't replace good bearings just because they were made in Japan. Also on the bench I think I have been able to get the case to engage in 4HI. You can't really tell how much play is in the chain with the case split and the shafts not aligned. If there is no obvious wear or damage I would put it back together, fill it with ATF and run with it. Now would be a good time to replace your speedometer gears also if the teeth are badly worn.
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Thanks for the info. I really wasn't looking to scrap the bearings, but I had read where some people were less than stisfied with the overseas bearings. Couldn't remember if it was the jap bearings, or the Chinese ones. Since they are in good shape now, I'll be leaving them alone.
As for the chain, I can slip the case back together, to support the ends of the shafts, and the chain flexes a bit, but nothing I would call excessive. I'll leave it alone as well.
The speedo gears look great. All in all, everything inside the case looks good. The seals were hard and dry, but I already have them swapped out for new ones, so I'll be OK there.
It still perplexes me as to why I can't get the thing to engage the chain in 4hi. Every other position works as it should. It's just not turning the front shaft in this position for some reason. I'll tinker with it some more before I put it all back together.
Thanks again for the info.
Jay