1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

T86 Rebuild Questions: Parts + Parts Source

Discussion in 'Early CJ5 and CJ6 Tech' started by teletech, Aug 26, 2016.

  1. Aug 26, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    I know Novak has some sort of special sealed input-shaft bearing for the T90 that supposedly doesn't leak like the felt seal but they don't sell one for the T86. Has anyone done the research to see if such a thing might exist as a standard part or perhaps a 2-sealed bearing and I could peel out the inner seal.

    With sitting exposed for so long (27 years), the bearings feel chunky so I'm going to replace them and get a small-parts kit while I'm replacing second gear. Are there really better and worse bearings for this application or are they all about the same so should I just go buy some based on price?
    I was even willing to pay the extra cost premium to buy the stuff from Novak since I was buying their fancy countershaft but they didn't do a full parts kit, etc. anymore.

    I'm also wondering about the popular wisdom on seals of late... do I use the seals dry, put a thin coat of something one them, or ditch the gaskets and just use Motoseal Black like modern cars?
     
  2. Aug 27, 2016
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    21,437
    The main differences between the T-90 and the T-86 are the main shaft splines (straight vs spiral, resp) and the sliding gears (again, straight vs. helical). This means that the gears cannot mesh with each other, but the case and all dimensions are the same. You can take the gears of a T-90 and build a T-86 with all T-90 gears. Herm sells a rebuilt T-86 replacement like this - Rebuilt Modified T-86 $550 | Herm The Overdrive Guy

    A sealed front bearing for the T-90 should work fine in a T-86. Are you sure that the T-86 does not have a neoprene seal in the bearing retainer? Picture of the T-86 small parts kit shows a seal:
    [​IMG]
    There is no seal on the output, so I'd guess the seal is for the input shaft bearing retainer. Thus a sealed bearing is not needed for a T-86.

    I recall that Herm has looked into replacement bearings for these transmission. My recent experience is that, for some of these applications (ie T15/T18 front main bearing) there is no option other than the Chinese bearing that Crown et al offers. If you can find a supplier that will select one for you, the smoothness varies from one to the next. If you can feel roughness in the bearing, reject it and get another.

    Seals and gaskets are two different things. Gaskets are pretty easy. I would use a thin coat of Ultra Black, or CopperCoat. Gaskets on a transmission are going to seal if you clean the surfaces. For seals, I use a thin coat of Permatex #2 on the steel shell for installation and then lube the seal for assembly. Transmission oil is fine, although I use Asemblee Goo https://www.amazon.com/gp/product/B000B8YDUO/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1 for the loose bearings, which would work too. You need to fully immerse the big bearings in transmission oil before assembly.
     
    Last edited: Aug 27, 2016
    OzFin likes this.
  3. Aug 27, 2016
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    11,735
    Do not assemble the transmission without the gaskets. The gaskets are required to set clearances.
     
    OzFin likes this.
  4. Aug 27, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    Oops, on closer inspection it appears my T86 has T90 gears since at least the reverse idler is straight-cut. I guess I'll need a T90 second gear.
    Should I just buy a crown second or find an old NOS jeep one?
    OK, so all the bearings are imports now, that's sad of course but it lets me move on.
    I gather the Novak front seal is used in addition to the factory seal but if the boxes are so close I'm surprised they didn't think it was the same bearing.
     
  5. Aug 28, 2016
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    21,437
    If you are changing the gear because the bushing inside is worn out, a used gear will probably have the same problem.

    What Novak front seal? The T-90 can be fitted with a sealed bearing, that is, pre-lubricated and permanently sealed on both sides. No oil goes through. sealed bearing - Bing Likely expensive, especially when it's not needed.
     
  6. Aug 28, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    The fronts of the teeth are a bit battered on the old gear and since it was popping out when the transmission was removed I didn't want to take the chance.
    I'll make sure all bushings are in good shape and replace anything even slightly questionable.
     
  7. Aug 28, 2016
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    21,437
    Typically the T-90s pop out of second when the bushing inside the gear wears and the gear skews on the shaft when decelerating. This pushes the shift collar away from the gear and it comes out of gear. Worn synchro teeth on the gear or a worn synchro hub would make this worse.
     
  8. Aug 28, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    Thanks for the information. I'll get a bushing while I gather parts.
    The symchro teeth onmy current second are a bit chipped up but I was surprised that would have been enough by itself, now I know where else to look.
     
  9. Aug 29, 2016
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    21,437
    The bushing is pressed in to the gear. I don't know that it's available separately. It would probably be cheaper to buy the new gear than repair an old gear. You could ask Herm ...
     
  10. Aug 29, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    I'm expecting to buy a new gear so I should be fine then,
     
  11. Aug 29, 2016
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
    Joined:
    Feb 3, 2013
    Messages:
    680
    Several parts guys MAY get confused...If you own a caliper measuring tool, measure everything several times on all the rounds, wear if normal or excessive, can change a measured distance. At some point gears are gears, make sure the photo is the same and the numbers match. It is a horror story to get a guy who you know knows better CAN still screw it all up.
     
  12. Sep 1, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    Ah, well now that I go back and look at the worn parts more carefully, the 2-nd gear bushing is totally shot. The synchro teeth on the gear are a bit battered but not really all that bad.
    I'm inclined to replace it since it's all apart anyway, but which second? I notice there are several sources although Crown and Omix-ADA seem to be the main source. Is there a better second gear?
    I do have a used gear, found in a coffee can of old gearbox guts that has an intact bushing and slightly better synchro teeth, how does used but original stack up against new-made?

    Unkel Dale: thanks for the advice. Rest assured there will be callipers, and feelers, and dial indicators present during reassembly, particularly considering I found the gearbox disassembled and spread around the garage a bit!

    Speaking of spread-out, I finally set it all in a rough pile... it's a lot of bits... bellhousing adapter, transmission, transfer case, overdrive, pto spacer, power take-off....
     
  13. Sep 1, 2016
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
    Joined:
    Feb 3, 2013
    Messages:
    680
    The used gear is or has already been replaced because it is NOT assembled, is my first reaction.
    My next thought is that start labeling the parts with wire tie tags and a marker. If you are really bold assemble it in the dining room table. This may NOT HELP.
    Get a schematic or exploded view 8 x 11 inch print out and have it blown up to 24 x 48. This MAY help.
    After you measure stuff just look at them assemble THE TRANNY DRY. Simple light oil on everything to look for lash issues.
    Do go to you tube and view schultzhaus guy to t 90 assembly. He made his own assembly tools, good stuff there.
    On my final assembly I set up the video and paused regularly to review. This assembly IS very doable for a newby. This t 90 of mine (t86 very similar) was my first in 35 years. Familiarity helps. The green goo is wonderful stuff.

    Tupperware type bins for each, tranny, OD, PTO, TO SEPARATE STUFF.
     
    Last edited: Sep 1, 2016
  14. Sep 3, 2016
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
    Joined:
    Feb 3, 2013
    Messages:
    680
    The sealed gear on front CAN be replaced with a sealed gear, I did that. You will also get a small rubber plug that goes into the oiler hole in the front of the case for the original oiled bearing. This is how schultzhaus guy did his in the video.
     
  15. Sep 3, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    I went ahead and ordered the sealed front bearing, along with a Novak 2nd gear. The gear was more money than other sources by $20 or so but I was placing an order anyway and Novak had already proved they had good turnaround time etc.
    Thinking on it, another bonus of the sealed front bearing is that it's ok when you loose all your lube back into the transfer case on a long hill climb... well the rest of the gearbox is still at risk but at least it's something.

    The transmission is the only thing actually disassembled, the transfer case, etc. are still in chunks. The fun is going to be figuring out all the nuts, bolts, brackets, and other bits to get them all installed and the controls hooked up.
     
  16. Sep 29, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    Incidentally, Novak is shipping Crown second gears. It looks fine though the busing isn't as excitingly textured inside as a factory one.
    I got my input bearing off, no joy with a puller or press so I just split it off. The new sealed one (made in Japan) pressed on just fine.
    it looks like I need rubber plugs for both the gearbox case and inside the main shaft?
    I have an assortment of counter-shaft thrust bearings, the little tabs on the bronze one perplex me: The new one has them, one used one doesn't have them at all and another has them but they are pounded-flat. I'm beginning to wonder if it's a peculiarity of using T90 parts in a T86 case but I'll re-watch the video and see if there is an explanation.
     
  17. Oct 15, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    That's interesting...
    There is a hole in the gearcase I have to block, but there is also an oil hole in the primary input shaft that I need to figure out how to block-off it seems.
    Anybody else have this hole, it's drilled from in front of the front main bearing into the center of the input shaft?

    Also, on my (T-90) shift tower: I went to pull the poppet balls and the ones in there are two different sizes, the small parts kit only has the smaller one but it really looks like my rails would prefer to have the larger balls in both locations.
    Oh, one of the springs was broken!
     
  18. Dec 8, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    OK guys, I could use a little advice here it seems.
    I rebuilt my gearbox and it worked fine on the bench.
    Then, I attached the transfer case and now the countershaft seems really bound-up. What gives?
    The output shaft is free, even through the transfer case. The input shaft also seems free, for the few parts of an arcsecond it can turn before the gear mesh with the countershaft stops it.
    I'd rather not have to pull the transfer case back off since I'll have to order a new gasket, etc.
     
  19. Dec 11, 2016
    teletech

    teletech Member

    Santa Cruz, CA
    Joined:
    Aug 20, 2016
    Messages:
    187
    Well, I wound up pulling the transfer case and such after all.
    The sheetmetal lock-plate for the reverse idler and counter-shaft was fully seated but still pinched between the gearbox and transfer case. I had to trim the locating ears a bit but I feel confidant that once my new gasket arrives thing will go back together smoothly.
     

Share This Page

New Posts