dan123dbl

I'd be surprised if the shims in there will still be the proper thickness.

I asked a guy what the best way to set the pre-load on the getrag was, and he told me he does it all by hand. He can "feel" the correct pre-load with his finger. (the pre-load needs to be within 0.002" to be right if i remember correctly..)

And that's why I rebuilt my transmission myself.

thrub

Hopefully my parts will be here Saturday and I can find out. I think that I will use a dial gauge to measure preload. My finger is only calibrated to 10ths of an inch.

thrub

Well I stripped all the aluminum off of the syncro sliders tonight with muriatic acid. Worked slick. They look good as new with very little effort. Process is very stinky, ventilation is good. Started assembling the 1-2 syncro and got the first ring installed without too much trouble using vaseline. Actually a lot easier than it sounded. Went to install the second ring though and it is ever so slightly warped. It was the ring that was on the worn out blocker ring. I guess I should have checked that a little closer when I disassembled it. Looking at it now it is a little darker than the other side was. So I guess I phone tomorrow and get a few more parts on the way.

thrashingcows

I missed a couple parts that needed replacing on my NV4500 rebuild too....didn't realize until I was almost done putting it all back together. I then had to wait and order more replacement parts...Doooh!

I had to make up quite the set-up to load the up the main shaft so I could check the pre load. I ended up putting the case under the work bench, then blocking a small 3 ton bottle jack under the bench top facing down. Then loaded up the main shaft so I could check pre load. I had to do this half dozen times until I got it set right....lot of work, but glad I took the extra time to set it right.

mknittle

Hind sight is always 20/20 vision.

thrub

Parts all showed up this morning. Except for the ones that I forgot to order. The new shift tower has a vent in it on the top between the shifter an the three humps on the front of the case. My old one definitely does not have this feature. Maybe that is why the seal was pushed out the back?

thrub

Well with the parts that I have I was able to install the reverse idler and the countershaft. Looks like I will have enough shims for it. I just quickly measured it tonight and with the shims I have I can get .008. Book says .006 to .008. I will check my measurements and math later when I'm not so sleepy. Wouldn't be the first time that I added wrong. For what it's worth my initial measurements are .007 less than what was in there before. So I'm glad that I checked.

thrub

Alright so I went out this afternoon and measured a little more carefully and checked my adding and came up with a new number. Measurements were taken with a dial gauge. Not exactly the tool for the job but it worked.
So what I did was measured the shim bore on the tail housing which was .101. Then I made sure the race was seated fully by tapping on it while rotating the counted shaft. Then I measured the amount the race protruded from the case which was .043. The manual says to subtract .043 from .101 and add .006 to .008 to that number and you will get the required shim thickness. So I need .064 to .066 worth of shims. Anyone see any errors or omissions? Shim pack is still different than what was in there. Original shim pack was 3x.018 and 2x.008.

dan123dbl

The math sounds correct to me. The dial gauge could produce different results each time though in my experience. The slightest change in how square you have it to what you're measuring can change it by a few thousands.

I used something like this to get my measurements : Depth Gauge | Princess Auto (but with a dial gauge and way more precise)



When you're taking your measurements, do you have the input shaft retainer on and the transmission sitting vertically with the input shaft facing down?

I think that's what the manual suggests.

thrub

A depth gauge like that would be the proper tool. Maybe not that particular one because it doesn't look like it measures fine enough. I don't have the input shaft in yet. I just measured the counter shaft and yes I did have it standing upright on the bench. I don't have all the parts I need yet to assemble the mainshaft.

dan123dbl

You need to make all your measurements with the mainshaft and input shaft installed. With the input shaft retainer torqued down.

And yeah that tool doesn't measure fine enough, but the shape of it was the intended example.

thrashingcows

When I did my NV4500 I just installed the shim pack that I took out and measured the end play. Then started adding, removing shims until I got the right reading. I ended up having to buy a misc shim pack from Quad4x4 to finally have the correct shims to get the right reading. Took a while, but I didn't have to do any math....

Alec

TC -- The Getrag bearings are pre-loaded -- so you have to do some math no matter how you measure.

Personally, I would use a cheap dial caliper w/depth gauge before trying to measure fixed dimensions with a dial indicator. But to each their own. And your process thrub, as described, is correct. I am surprised you are w/in .004 of the original shims.

bannerd

I tore my getrag apart when I rebuilt my W250. I used the new shims on the rear output shaft. I ended up using a press and a plate steel and just using my finger to get a feel. Obviously you don't want to shim over the lip and under the lip. You have to feel for it... normally when it's smooth then you know you're there. I ended up putting high tac all over the back of it and on the getrag cover. They used something similiar from the factory.. usually dried up though or you can't see it. I have 60,000 on the truck now and it shifts awesome. Keep in mind that you have to overfill the getrag. Using the top PTO cover hole barely covers the 5th gear, I find it best to dump it though the shift hole until it comes out of the top PTO bolt. From there add a quart.

I would like to try redline shock but I feel it would be too thick for the synchros.

thrub

I would agree that a dial indicator is not the proper tool. I tried using the back end of a dial caliper but that did not give very consistent results. At least the dial indicator was consistent moving back and forth multiple times. I am however going to try and find a proper depth gauge before the rest of my parts come. I have shim packs coming with the 1-2 syncro.