S4C Transmission Stuck in 5th after Rebuild
#1
Honda-Tech Member
Thread Starter
S4C Transmission Stuck in 5th after Rebuild
1999 EM1 with the factory transmission. I did a LS-VTEC conversion, and decided to put new bearings and carbon synchros in the transmission while I had it out, which I regret now. I put it all back together, the engine started, but if I let the clutch out (on jack stands) the wheels spin, at a speed that corresponds to fifth gear. The transmission would shift into all the other gears on the bench and in the car, although 5th felt a little vague and not clicking like the others, so I had some doubts. With the engine running it will not go into reverse even with the clutch in. With the engine running it will go into the other forward gears, but the transmission will not turn and the engine stalls when the clutch is eased out. Obviously, I didn't get it back together correctly. If anyone has any insight into these transmissions as to specifically what I might have done, or if there is something else wrong, I would appreciate it. I was 90% sure I had it right.
I have the manual and tried to follow it. It didn't seem like there were options. I found a pretty good youtube and I redid the main shaft to be sure, so I am most confident in the main shaft, even though that is where the 5th-R shifter is. Thanks in advance!
I have the manual and tried to follow it. It didn't seem like there were options. I found a pretty good youtube and I redid the main shaft to be sure, so I am most confident in the main shaft, even though that is where the 5th-R shifter is. Thanks in advance!
#2
Re: S4C Transmission Stuck in 5th after Rebuild
Just buy a rebuilt transmission.
#6
#7
Fish Twig
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Re: S4C Transmission Stuck in 5th after Rebuild
1999 EM1 with the factory transmission. I did a LS-VTEC conversion, and decided to put new bearings and carbon synchros in the transmission while I had it out, which I regret now. I put it all back together, the engine started, but if I let the clutch out (on jack stands) the wheels spin, at a speed that corresponds to fifth gear. The transmission would shift into all the other gears on the bench and in the car, although 5th felt a little vague and not clicking like the others, so I had some doubts. With the engine running it will not go into reverse even with the clutch in. With the engine running it will go into the other forward gears, but the transmission will not turn and the engine stalls when the clutch is eased out. Obviously, I didn't get it back together correctly. If anyone has any insight into these transmissions as to specifically what I might have done, or if there is something else wrong, I would appreciate it. I was 90% sure I had it right.
I have the manual and tried to follow it. It didn't seem like there were options. I found a pretty good youtube and I redid the main shaft to be sure, so I am most confident in the main shaft, even though that is where the 5th-R shifter is. Thanks in advance!
I have the manual and tried to follow it. It didn't seem like there were options. I found a pretty good youtube and I redid the main shaft to be sure, so I am most confident in the main shaft, even though that is where the 5th-R shifter is. Thanks in advance!
HMM..:thinkingemoji:
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#8
#9
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Re: S4C Transmission Stuck in 5th after Rebuild
Have you ever? It's very easy for a gear to engage when trying to line up all 3 shift forks with the interlock while also trying to get them in their respective holes in the case along with the mainshaft and counter shaft all at the same time.
#11
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Re: S4C Transmission Stuck in 5th after Rebuild
#12
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Thread Starter
Re: S4C Transmission Stuck in 5th after Rebuild
I appreciate all the comments.
I have already sunk $550 in parts into this transmission, so I don't really want to just buy a rebuilt. But that is still on the table if necessary.
These transmissions are difficult to assemble, but not that complicated in principle.
The manual is a bit vague. Its exploded diagrams do not show components in order of assembly. And some drawings do not show parts in sufficient detail to determine their orientation.
But what really makes Honda transmissions difficult is that the transmission is completely unrestrained until you glue the case together. Also, the intermediate shaft is not in position until the case is glued together and you pry it up. So there is no way to tell if you are correct or not until you are done. There is no way to test anything. And you really don't know if it's right until you install the axles, connect the shift linkage, fill it with fluid, and spin the input shaft. Which is where I am at. My plan is to “double check my work and check the FSM again”… with an emphasis on the interface between the shifter and the 5-R shift fork.
So thanks for the input. Let me know if anyone has any other ideas.
I have already sunk $550 in parts into this transmission, so I don't really want to just buy a rebuilt. But that is still on the table if necessary.
These transmissions are difficult to assemble, but not that complicated in principle.
The manual is a bit vague. Its exploded diagrams do not show components in order of assembly. And some drawings do not show parts in sufficient detail to determine their orientation.
But what really makes Honda transmissions difficult is that the transmission is completely unrestrained until you glue the case together. Also, the intermediate shaft is not in position until the case is glued together and you pry it up. So there is no way to tell if you are correct or not until you are done. There is no way to test anything. And you really don't know if it's right until you install the axles, connect the shift linkage, fill it with fluid, and spin the input shaft. Which is where I am at. My plan is to “double check my work and check the FSM again”… with an emphasis on the interface between the shifter and the 5-R shift fork.
So thanks for the input. Let me know if anyone has any other ideas.
#13
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Re: S4C Transmission Stuck in 5th after Rebuild
When you open it back up, make sure you haven't left the 5th gear synchro spring out of the transmission. As others have said, it may be the interlock / change holder, also.
Stupid question, but are you sure your clutch is adjusted properly? Some of the symptoms sound like this could be happening.
Stupid question, but are you sure your clutch is adjusted properly? Some of the symptoms sound like this could be happening.
#14
Re: S4C Transmission Stuck in 5th after Rebuild
Of course
It may be easy for you and me, but does that mean that everyone should and does have the same aptitude? Of course not. Recommending the OP to buy a rebuilt transmission might in the end save him time, money, and frustration. Or do you think everyone should keep beating their head on the wall without considering other viable options?
Similarly, do you think everyone should attempt to rebuild their block? Think about it.
It's very easy for a gear to engage when trying to line up all 3 shift forks with the interlock while also trying to get them in their respective holes in the case along with the mainshaft and counter shaft all at the same time.
Similarly, do you think everyone should attempt to rebuild their block? Think about it.
#15
Fish Twig
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Re: S4C Transmission Stuck in 5th after Rebuild
which, again, I stated he needs to take it apart. its a pain but guess what, you just gotta do what you have to. There's no shifting combination that is gonna get you to free up that reverse
#16
Re: S4C Transmission Stuck in 5th after Rebuild
Unless you are willing to drive to the OP's location and tutor him on rebuilding a manual transmission, then you may be just leading him to make a bad situation worse.
#17
Fish Twig
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Re: S4C Transmission Stuck in 5th after Rebuild
thats the only way I see how to confirm what went wrong inside the transmission unless there's some magical camera that can weave its way around gears going through the vss or fill hole.
#18
Re: S4C Transmission Stuck in 5th after Rebuild
#19
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Re: S4C Transmission Stuck in 5th after Rebuild
Use the guide in the transmission forum.
#20
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Thread Starter
Re: S4C Transmission Stuck in 5th after Rebuild
Didn't think to turn the shaft in each gear. That would have caught it probably.
#21
Honda-Tech Member
Re: S4C Transmission Stuck in 5th after Rebuild
The 800 pound gorilla in the room: Changing anything that changes the installation height of the main shaft requires checking/re-shimming the main shaft end play distance. Verifying this is a very specialized process and requires unique equipment to properly test and set. Most DIY'ers skip past this part in the FSM and quietly cross their fingers and hope everything works great after re-assembling the transmission. Some people just get lucky and the parts changed simply fall within the acceptable range of end play clearance. Then they say that working on manual transmissions is easy. In this case, it appears that if the OP did everything right inside, he just wasn't lucky. Now I am not ruling out the possibility of another issue, but if after opening up the trans and seeing no "smoking gun" as to what you have already done... you must consider what I have outlined.
The items that would require this test and re-shimming would be any of the following: The mainshaft itself, clutch housing main shaft bearing, trans case main shaft bearing, 3/4 spacer collar, 5/R spacer collar, 3/4 hub or 5/R hub.
The items that would require this test and re-shimming would be any of the following: The mainshaft itself, clutch housing main shaft bearing, trans case main shaft bearing, 3/4 spacer collar, 5/R spacer collar, 3/4 hub or 5/R hub.
#24
Honda-Tech Member
Thread Starter
Re: S4C Transmission Stuck in 5th after Rebuild
The 800 pound gorilla in the room: Changing anything that changes the installation height of the main shaft requires checking/re-shimming the main shaft end play distance. Verifying this is a very specialized process and requires unique equipment to properly test and set. Most DIY'ers skip past this part in the FSM and quietly cross their fingers and hope everything works great after re-assembling the transmission. Some people just get lucky and the parts changed simply fall within the acceptable range of end play clearance. Then they say that working on manual transmissions is easy. In this case, it appears that if the OP did everything right inside, he just wasn't lucky. Now I am not ruling out the possibility of another issue, but if after opening up the trans and seeing no "smoking gun" as to what you have already done... you must consider what I have outlined.
The items that would require this test and re-shimming would be any of the following: The mainshaft itself, clutch housing main shaft bearing, trans case main shaft bearing, 3/4 spacer collar, 5/R spacer collar, 3/4 hub or 5/R hub.
The items that would require this test and re-shimming would be any of the following: The mainshaft itself, clutch housing main shaft bearing, trans case main shaft bearing, 3/4 spacer collar, 5/R spacer collar, 3/4 hub or 5/R hub.
#25
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Re: S4C Transmission Stuck in 5th after Rebuild
You can get a so-so straight edge and set of feeler gauges for around $30. Those will allow you to check the stack-up to calculate your thrust shim thicknesses for the mainshaft and the differential. The tools to check the thrust clearance are the pricey ones. If it makes you feel any better, I've rebuilt a few Honda transmissions (bearings, seals, synchros) and not had to change shims before. But...you should still check.