Discussion in 'Early CJ5 and CJ6 Tech' started by truckee4x4, Jun 21, 2020.
Fino beat me to it by seconds!
Yes, as mentioned by FinoCJ and givemethewillys, it provides a little better visibility if/when leaks develop.
For what its worth, most folks think the single-stick D18 came out with the Dauntless V6 in '66. Actually, the single-stick was introduced in the MklV Tuxedo Park for the '64 model year, but the T90 was a column shift. This left most of the floor unobstructed for a middle passenger on the 60/40 bench seat.
Your 3rd photo in post#11 shows the hi/lo shift rod still in the transfer case, with the fork still in the case. The shift rod with fork in that is loose in that photo is the front drive in/out, so you have 2 shift rods, but one lever controls both. You need to keep the interlock "pill" between the two rods in that front housing to enable the single lever to move both rods as they were intended. The pill acts in the long flat recess on the hi/lo rod that is still assembled with the transfer case. It ends up between the two shift rods when properly assembled.
Single stick D18's were offered with the V6 in early CJ's and were were assembled with a bigger intermediate shaft, bigger input bore, and D20 casing.
Novack's "knowledge center" is a great reference.
The Novak Guide to the Dana Spicer Model 18 Transfer Case
My Jeep has a T86-AA case in it, but with T90 gears. Guessing the T86 was likely original?
Also, do you guys who rebuild your cases put gasket sealant on the paper gaskets behind, and under/around the lips of the four metal seals? Mine also had a fat bead of black silicon around the shift rod protrusions on the back outside of the case, is this a common leak spot?
The Novak site is partly correct, but they aren't aware the single-stick was used at least 2 years pre-dating the V6. The Tuxedo Park MKlV used the single-stick linkage with a small bore case. These were only found on F134 Jeeps with the remote/column shift T90. These were a limited production model with about 5200 being produced in this configuration.
you refering to the the spacer shims that go between the case and rear bearing cap? If so, a lot of people use a thin spray sealant like Permatex Copper spray on both sides....I found the spray sealant added a bit of thickness and had to redo with one less shim.
If you are referring to the standard oil seals for the input and output shaft - metal doughnut with the rubber inner lip, then yes, smearing a layer of RTV around the outer edge is SOP...and add a bit of lubricant to the rubber inner seal that goes on the shaft.
Also, there is a part number for a thinner output shaft seal that will allow you to fit two of the seals at one time, providing a double seal and moving the seal surfaces away from a common wear point on the output yoke. This is a common update to reduce output shaft leaks. These can be used on both the front and rear output shafts.
NATIONAL # 473229
It's hard to make sense of what sealants/products to use where, as there seems to be some conflicting info out there, and I am a beginner without lots of previous experience to rely on.
Thanks @FinoCJ for the info. I did put Super 300 sealant (not RTV) on these metal "doughnut" seals, and sprayed sealant on the shims behind the bearing cap.
For example, Novak says to use RTV + a paper gasket on the oil pan and PTO cover:
And Permatex says on it's "10 most common gasketing mistakes" page to not use RTV but to use sealant (I assume they mean #2, or Super 300):
Just trying to do whatever's going to give me the best chance of not having leaks!
Here are a couple more references to add to the plethora of information.
Ultimate Dana 18 seal it thread
MODEL 18 T Case Rebuld
Been using RTV Ultra Black and The Right Stuff on the gaskets, shims, and bolt threads for pushing 30 years with good results. On the shift rail caps I put a thin coat around the open end and gently drive them in with a dead blow hammer. This creates a positive seal without a big mess. They do tend to seep here.
The Right Stuff and Ultra Black tends to soak into the gasket slightly helping eliminate oil wicking through the gasket.
I went from the single to the twin-stick when I rebuilt the D18 (added the OD, and went to the T14 at the same time) as I got tired of fighting with the linkage to shift in and out of 4wd as it was rusted due to lack of grease/oil by a prior owner.
I used aviation form-a-gasket on both sides of the paper and on the bolts, as they can (and do) leak.
You are right. Ya learn something new every day.........
Hey guys can you help me sort something out? As you may recall my case do not have a parking brake on it, and in my unused parts bin there was the emergency brake backing plate and drum and a companion flange (On the left) that looks to be a bit taller than the flange that came off the case (on the right). The flange that was with the emergency brake parts also seems to have a seal groove in it.
Can I reinstall the flange that came off the case, or do I need to clean up and use the taller one? @donny or @FinoCJ I'd love to know what you guys think?
View attachment 59114
Do all the shift linkage parts get painted as well or are they all bare metal?
And also, is it normal for there to be a slight rub on the shoes / ebrake drum with the star wheeels all the way in?
This is just me, but on the shift linkage bearing surfaces or where there's metal on metal, you could leave those bare metal and only paint the other side(s). Grease them up good and periodically clean them and relube.
I hate that these parts are exposed to the hostile environment under there and are often dry, but ..
Don't know about your other question.
yes, but they didn't have a bigger intermediate shaft than the last generation small hole ones. my '61 has a small hole twin stick with a 1-1/4 shaft, which was what was in the large hole cases. i think the 1-1/4 shaft was introduced sometime in the 50's, not at the release of the large case D18
looks like either would work??? i'm nhot an expert, but they seem to both be compatible, as the shorter one seems to have a shorter mounting surface for the driveshaft flange to make up for the difference. personally i would get a repair sleeve for the one with a groove and use it
Correct. My dad's first Scout had a twin stick D18, identical to Jeep. The second one, however, had a D20 with levers marked Front and Rear, H-N-L. Interlocked. of course, to prevent 2WD Low on either end, or, Heaven forbid, crossing them up! Being in high school at the time, I was oblivious to the Dana/Spicer nomenclature, but I sure thought that second one was really cool. About 20 years ago when I converted my early Chevy van to 4WD I installed a D20 behind a BW Super T10 using an AA adapter. Of course I deleted the interlock pill(s), resulting in totally independent range selection front and rear. Caution is advised.
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