Any Chevy/transfer case/drivetrain experts out there?

BDJeff said:
1st thru 3rd isn't too bad but it really starts to scream once I get into 4th and 5th and up above about 50 MPH. The engine is turning about 3000 RPM at 65 and it's pretty loud in the cab. Although there's little to no sound deadening installed so that may amplify the problem. The PO said it was "normal" because the case has straight cut gears. Even heard of that explanation?
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It's not that the gears are cut different it's that the D20 isn't turning as many parts because it's a straight line from input to output -- if you put a D20 in 4wd on the hwy you'll start to hear some sound out of it...

I've never (not!) heard a D18 be quiet... I wear earplugs when I take my Wagon on the hwy -- soon as I'm above 55 I think about putting 'em in!
I'm sure my D18 needs attention but I'm also sure it was just as noisy 20 years ago and with all the hwy miles I've done at 75 I'm sure if it was really worn out it'd a-blown-up...

When the countershaft bearings wear they allow misalignment of the gears -- the more misaligned, the more they howl...

You'll know you went too far when you smell burned gear oil and they run silent...
 
Well, I supposed my truck is a stock L134 truck. So it is limited hp and will top out at 45-50 mph since it does not have an overdrive. Mine is nice and quiet. The Dana 18 wasn't designed to be a high speed transfercase.
 
The transfer case looks like the original style (no parking brake) for your jeep. The date the case was cast is partially hidden in your picture, right under the G18 next to the cast in screw head. Could it be June (6?) of what ever year is just out of the picture?
 
Sprint 6 said:
Well, I supposed my truck is a stock L134 truck. So it is limited hp and will top out at 45-50 mph since it does not have an overdrive. Mine is nice and quiet. The Dana 18 wasn't designed to be a high speed transfercase.
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I won't say you're wrong...
In stock form with my 226 in o/d I could do 65 with 30" tires and 4:27 rear axle...
I think having/using the warn o/d causes the D18 to spin even faster...

I'm looking fwd to getting my D18 on my new work-bench and seeing how much improved it will be with new parts -- I picked up a Crown rebuild kit 20 years ago or so at a swap meet -- so I'm hoping the kit is actually 30 or more years old -- I wouldn't buy anything from Crown or Omix-Ada today...
To keep the thread relevant -- check out Novaks rebuild kit for the D18 with hardened counter-shaft -- supposed to be the better solution...
https://www.novak-adapt.com/catalog/transfer-case-parts/dana-18-parts
 
banman said:
I won't say you're wrong...
In stock form with my 226 in o/d I could do 65 with 30" tires and 4:27 rear axle...
I think having/using the warn o/d causes the D18 to spin even faster...

I'm looking fwd to getting my D18 on my new work-bench and seeing how much improved it will be with new parts -- I picked up a Crown rebuild kit 20 years ago or so at a swap meet -- so I'm hoping the kit is actually 30 or more years old -- I wouldn't buy anything from Crown or Omix-Ada today...
To keep the thread relevant -- check out Novaks rebuild kit for the D18 with hardened counter-shaft -- supposed to be the better solution...
https://www.novak-adapt.com/catalog/transfer-case-parts/dana-18-parts
Click to expand...

On my "to do" list. Could be a while before I get to it. Looks to be three different kits depending on the main shaft diameter. I guess a call to Novac first would be a good idea to make sure I've ordered the right one.
 
BDJeff said:
On my "to do" list. Could be a while before I get to it. Looks to be three different kits depending on the main shaft diameter. I guess a call to Novac first would be a good idea to make sure I've ordered the right one.
Click to expand...
The shaft pokes out the back of the x-fer case enough for you to easily measure with a caliper...
What came on the truck originally and what's on there now may not be the same...
As a general statement -- the larger diameter shaft (and bearings) found on later year boxes is a strength improvement.
 
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