Strange R154 problem, 7m swapped celica

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speedfreak426

New Member
Mar 31, 2008
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Brighton, MI
This is in my 1977 Celica with swapped drivetrain
7M-GTE, R154, Mopar 8.75 axle, 9psi.


I got stranded last night, sitting at a stop light I went to go and the shifter just flops between first and second like it isnt connected to anything, the shifter moves into first and second but nothing in the trans moves, and it wont go into 3rd 4th 5th or reverse at all, no grinding no nothing, it just seems to have a solid obstruction and wont move out of neuteral except for 1st and 2nd, which does not do anything at all.
Clutch feels fine but it does not change anything, it has the same problem weather the car is running or not, clutch in or out, all the same, it rolls fine when pushed and makes no strange noises.

Broken shift fork? I really have no clue. All I know is that my buddy had to flat bed the car back to my house last night

I did a search and did not find anyone that has had the same problem.
any ideas on what it could be.


I will have to pull the tranny and I am not looking forward to it, I have to remove the engine otherwise it wont come out! small transmission tunnel FTL.

Damnit!!!
 
black89t

black89t

boost'en down 101
Oct 27, 2007
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detents or interlocks got f'up with 3-4 rail and/or r-5. and 1-2 shift fork i'm guessing the pin or bolt wiggled out i forget what holds that fork. so all your doing is sliding a rail. its not moving the fork. i don't think your going to be able to fix that without pulling the tranny. i could be wrong though.

oh and a broken shift fork would sound horrible. there would be chunks of metal being tossed around. and did it happen instantly or have you had problems before. also how smooth is the movement between 1-2.
 
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joliroger4

joliroger4

Flying Dutchman Pilot
Apr 4, 2005
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You most likely disengaged the shift select lever from the 3 shift heads. Easy fix, you'll see when you open it. Just gotta make sure nothing is broke when you are in there since that really shouldn't happen.
 
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kingofyo1

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Oct 22, 2008
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mountain home ID
situations like this are usually called fm. you have no idea how it got like that or what caused it, huh? Did you hit a bump at the wrong angle or did something really effing heavy pop up from the pavement and hit your tranny at just the right angle to dislodge it?
 
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speedfreak426

New Member
Mar 31, 2008
380
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Brighton, MI
kingofyo1;1165145 said:
situations like this are usually called fm. you have no idea how it got like that or what caused it, huh? Did you hit a bump at the wrong angle or did something really effing heavy pop up from the pavement and hit your tranny at just the right angle to dislodge it?
Click to expand...

Nope.... smooth road, just stopped at a stoplight and put it in neutral and that was that, stopped working. I ground third gear under WOT about 5 miles beforehand but it shifted perfectly fine afterwards until I came to a stop and then I was dead in the water.
 
black89t

black89t

boost'en down 101
Oct 27, 2007
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at this point there really isn't much one can do over the internet. your going to have to pull it and take it to a tranny shop. it doesn't sound like you have a good enough idea of whats going on in there to tear one appart. also the chance of the the shift select lever from the 3 shift heads disengaging is very slim. especially how it just happened out of knowwhere. also your symptoms don't lead to that. that rail can only move so much. actually its practically impossible for that to happen and have it stuck in nuetral. i'm still betting on the 1-2 shift forks pin was just slowly getting worked out then in finally fell out. like i asked before how smooth is the movement when you shift from 1st to 2nd. does it feels as if its just floating when you go from first to second. like there isn't any obstruction (spelling).

edit: drain the fluid and see if you have any surprises with it.
 
joliroger4

joliroger4

Flying Dutchman Pilot
Apr 4, 2005
264
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16
New Jersey
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Then why can he not engage 3rd 4th and 5th? I assume you are talking about the spring pins that have to be hammered in with a punch? Those only apply to the reverse shift head and reverse shift fork so would not apply in this case anyway. If either pin fell out he'd still be able to shift into all forward gears. If one of the shift fork shaft snap rings came off, he could very easily jump the shift select lever outside of the 3 shift heads since the whole point of those snap rings is to prevent the shift fork shft from traveling too far and allowing the lever to jump out. I am not saying the shift select lever def jumped, but I am saying the problem is in that area of the lever and the shift heads and the cause could be a lot of things.
 
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speedfreak426

New Member
Mar 31, 2008
380
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Brighton, MI
Thanks for the input guys, I was just looking for some info on what "could" have happened before I pull it apart.

I will be doing this myself as one of you suggested against. I wont have a problem pulling it apart or fixing it, I have done a few transmissions before but just not the R154. anyways, I'll keep you updated on whatever i find out.
Thanks
 
black89t

black89t

boost'en down 101
Oct 27, 2007
951
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0
36
humboldt, ca
black89t;1165329 said:
at this point there really isn't much one can do over the internet. your going to have to pull it and take it to a tranny shop. it doesn't sound like you have a good enough idea of whats going on in there to tear one appart. also the chance of the the shift select lever from the 3 shift heads disengaging is very slim. especially how it just happened out of knowwhere. also your symptoms don't lead to that. that rail can only move so much. actually its practically impossible for that to happen and have it stuck in nuetral. i'm still betting on the 1-2 shift forks pin was just slowly getting worked out then in finally fell out. like i asked before how smooth is the movement when you shift from 1st to 2nd. does it feels as if its just floating when you go from first to second. like there isn't any obstruction (spelling).

edit: drain the fluid and see if you have any surprises with it.
Click to expand...



I called it!!!!!!!!!!!

thats cool you did it yourself too. :bigthumb:
 
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