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t90 replacement?

Discussion in 'Early CJ5 and CJ6 Tech' started by RyanKnol, Mar 3, 2016.

  1. RyanKnol

    RyanKnol New Member

    I have a t90 (j?) behind a dauntless, with an adavanced adapters- adapter attaching it to the bellhousing. and a small bore d18. i blew up the t90 (broken teeth on cluster and input) and ive been looking for a replacement.

    ive done so much research my brain is dead, and now im even more confused.

    now rebuilding the t90 would cost almost 1000 bucks it seems. so im looking for the easiest options for replacement transmissions. something with less parts involved. the dauntless came stock with a t86? would that bolt to the stock bellhousing? what about the small bore d18 tcase? are there any other options?

    im broke, so im trying to do this as cheap as possible, cant affford to buy too many parts. but labour / welding / rebuilding, etc isnt an issue.

    any help would be awesome! the jeep has been off the road for a year now, i need it back for this summer haha

    thanks in advance
     
  2. SFaulken

    SFaulken Active Member

    T86 or T14 were stock behind the Dauntless
     
  3. pat w

    pat w Member

    Hi there..it shouldn't cost 1k to rebuild your t90. Herm has rebuilt units for $450 or rebuild kits for around $150. The cluster and input should be readily available as well. I would try a wtb here on this site for the parts you need and put what you have back together since you are on a tight budget
     
  4. oldtime

    oldtime oldtime

    The only thing that will be a near bolt in is another T90 J.
    Or a T86AA with the common T86AA adapter plate.
    Or a T14 with the same as above adapter plate.

    To fit the small hole transfer case ...
    You would need to use the T90 rear bearing retainer in place of the T86AA or the T14 rear bearing retainer.

    Albeit not cheap...Now might be the time to consider a T18 or some other 4 speed.
     
  5. 47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

    I was in the same situation as you. Blew up my t-90 behind the v6 and small hole d-18. Saw the cost of a rebuilding the t-90 and found an SM 420 for 75 bucks. Still had to buy the 500 buck adapter though, so it wasn't cheap, but cheaper and better than the t-90. The adapter was worth the money. To do again I would look for a jeep t-18 or deal with making one work or go SM465. Nothing bad about an SM420 except that they stopped making them in 1967 and parts aren't as easy to get.
     
  6. duffer

    duffer Rodent Power

    PM Daryl. My guess is that he can get you a usable, complete T90 J for less than Herm's rebuild kit. Around here, T90's are worth only scrap price.

    And as for the T86AA, it is generally considered weaker than the T90 so it isn't worth the effort to use one, especially if you have to buy it. If fact, most people with blown T86AA's end up using T90 guts in the T86 case for repairs.
     
  7. colojeepguy

    colojeepguy Colorado Springs

    If on a budget, rebuild your T 90
    Parts are cheap and it's relatively easy to work on.
     
  8. Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

    You should be able to find a T 90 for next to nothing, they are everywhere in the USA.
     
  9. nickmil

    nickmil In mothballs.

    Just for clarification (search function and all that) you can replace the large T-86AA rear bearing retainer with one from a T-90 to make it work with a small hole transfer case. In fact the T-86 and T-90 bearing retainers are commonly used by the aftermarket adapter manufactures (Novak, AA) so their products will fit both large and hole transfer cases.
    Cannot do that with a T-14. The T-14 uses a groove to fit the indexing retainer like a T-15. Completely different design.
     
  10. oldtime

    oldtime oldtime

    Yeah Nick is right on, I was mistaken.
    Been a while since I saw the rear of a T14.
    The T14 cannot accept the T90 rear adapter
    So basically what this implies is that the T14 cannot be mated with the small hole D18.
     
  11. Warloch

    Warloch Did you say Flattie??? Staff Member

    Depending on your decision - If you need some gears, PM me as I have some from T90s I stripped that are in good shape.
     
  12. RyanKnol

    RyanKnol New Member

    Well. i didnt expect it but i found a t98 with the adapter for the same bellhousing (looks home made or old ) with the longer input shaft, granny low. for cheap. everything will bolt up from what i can tell.

    now im just trying to find out details. looks like its the same sized pilot bearing, shafts are the same. but i remember reading that my t90j and the d18 shared some oil passages? anyone have any diagrams or knowledge of this?

    also, the 98 is white a bit longer, and looks like i might have to cut out a bit of the floor pan :(

    last thing is cross member... anyone ever do this swap? what did you do? anything to look for? or am i going to have to make a new one? maybe just redrill some holes and use the one from the t90?

    Everything internal looks good on the trans. but the top shifter cover is a bit rusty and the shift rods connector fork things (brain not function today) are a bit sticky? any good tips on cleaning out the trans before putting it in the jeep?
     
    Last edited by a moderator: Mar 7, 2016
  13. Patrick

    Patrick Super Moderator Staff Member

    Edited for language (!)
     
    cadwelder likes this.
  14. Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

    doing a transmission swap in a early can be Like "Opening a Can of Worms"
    it can be done but requires a lot of thinking .
     
  15. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    How do you know it's a T-98?

    The T-98 was never supplied with the Dauntless. Regardless, the floors will have to be cut back and new, larger covers made.

    The mounts for the T-98 or T-18 are different from the T-90 mounts. You are pretty much on your own, since this combo was never offered by Jeep. The later and similar T-18 is a popular swap today. Look t the Novak page - The Novak Guide to the Borg-Warner T18 & T19 Transmissions

    Oil is shared between the trans and transfer case with the Borg-Warner 3-speeds like the T-90, through the bearing and a small passage IIRC. The adapter between the T-98 or T-18 and the transfer case in Jeeps includes a seal, so there is no oil sharing.

    You will have to change the driveshaft lengths.
     
  16. Glenn

    Glenn Kinda grumpy old man Staff Member

    Regarding the T90 and the D18 sharing oil........none of my 3 Jeeps do. There is a hole towards the upper part of the T90 that is a vent to the D18, since the T90 doesn't actually have a vent off of the case. This is at least what I have determined, I know others have said they share oil so maybe in some other application that happens?
     
  17. eti engineer

    eti engineer Member

    I have a T-98 in mine and 2X on everything Timgr said. The T-98 weighs 245 lb by itself. Add the D-18 and it becomes a bit difficult to handle, even with a transmission jack, since the weight is very unevenly distributed. In order to line up everything, there are spacers that go between the frame and the cross member. The ones that came out of my Jeep were wood. Not sure if that was what was supposed to be in there, but I replaced them with metal spacers. They are close to an inch thick. I thought maybe the wood was in there for vibration dampening, but that really didn't make any sense, since the rear end of the T-98 mounts to the cross member with a large rubber piece as does the D-18. Below is mine after a rebuild and painted Good luck!!!

    Tranny and xfer case after painting gloss black.png Tranny ID stamp.png
     
  18. Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

    a T98 and 4 cylinder has one thing going for it . it's stock . adapting it to the GM bell housing is another thing all together
     
  19. eti engineer

    eti engineer Member

    So I have heard. That is why I have been advised that if I am going to change out my engine, I should sell the 134, the T-98 and the D-18 intact and go for something completely new. However, one of the major adapter manufacturers, I forget which one right now, told me they have adapters to adapt the T-98 to other engines. When I get ready to do it, I will research it and make a decision. I have yet to get the Jeep off-road, so I will see how it goes. If I like it, I then have to make a choice to purchase a trailer and tow it behind my Xterra. I guess I will see...
     
  20. Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor