No 5th or reverse gears after extension housing swap
 

Hey guys quick question here. I have a 1990 Rx-7 Vert. I swapped in a s4 transmission and then realized the crossmembers changed from s4 to s5. So I took the extension housing off of my S5 transmission and swapped it onto the s4 transmission. I had the transmission in neutral so that all the gears inside the transmission were even with one another making it simple to slide the shifter control rod back into place. I torqued everything down and got the car fired up and low and behold I no longer have 5th or reverse gears. I remembered not putting the little steel ball back in with the blind cap and spring on the shifter housing because it kept getting jammed in the other spring for the select lock spindle. Would that cause me to lose reverse and 5th gear? If so how can I get the ball back in without it jamming up on me? I've tried putting the select lock spindle in and tightening it down to compress the spring but the ball still ends up jamming in the select lock spring making the control rod jam up and not move. If the little steel ball is missing would it cause me to lose 5th and reverse gear? OR could it be that I did not have the shifter control rod aligned correctly with the gears? I had all gears level with one another and slid the control rod into the gear arms. I read that the steel ball, spring, and blind cap have something to do with 5th and reverse and figured one of you FC gurus would know. If anyone has any input I'd really appreciate it as I need to get my FC out of the garage a.s.a.p. Thanks

I just realized I posted this in the wrong section. If an Admin or Mod sees this please move it to the tech section for me, thanks.

I should've added that before I took the extension housing off the transmission I had 5th and reverse just had and still have a strong vibration when I raise the RPMs

I had a problem like that before and it turned out to be the reverse light sender switch was missing the washer on it and I guess it was too far In causing 5th and reverse not to go in.
Try removing that switch and testing if the gears go in without it on.

Thanks for the reply. I actually did swap the senders out for ones in better shape so maybe I forgot to add the washer. I will check that out and get back.

I found lastnight that my driveshaft was off from where it was bolted up originally by 90 degrees so I rotated it and bolted it back up but did not get to check if that was the cause of the strong vibration I am experiencing once I hit 2.5-3k. My Vert gets extremely loud when I get on it due to my exhaust set up and it was late. If not I have a few other areas to look at that could cause vibrations. Never had the problem before I installed the s4 transmission.

Tried turning the driveshaft and had no luck, still have the vibrating. Starting to think the driveshaft got bent somehow. I disconnected the plug for the reverse lights but cannot get a wrench up in there to take the sender out so I'll have to drop the crossmember to get at it and by looking at my old sender and feeling the one on the transmission now, seems like I forgot the washer but cant be sure. I bought a new car and lost interest in trying to fix the FC. Sick of the "rotorheads", sick of the attitudes, sick of the lack of help which seems its only the rotary community who slacks at helping and criticizes people for not knowing something, sick of spending money on a car that always has problems but yet I still don't want to get rid of the car. Looks like its just going to sit until I feel like working on and spending all my money on it again..

Right now I am at a stand still with trying to figure out the problem because I had to give up the heated garage for my stepdad for a few days while he changes his transfer case in his Ford Explorer. The FC is in another garage but with no electricity so I can't work on it until I get the other garage back. Is it okay to run the car with no driveshaft? Just thinking of ways to narrow down the vibration problem.

I may be wrong on this..BUT I remember something to the effect that there is a slight difference between the s4 and s5 trans,where the rear tail shaft has a counterweight on it???

BUMPSTART mentioned it in one of his answers,so you'd have to follow his posting history to find the info.

Found it.HERE: https://www.rx7club.com/2nd-generati...sions-1053147/

Yes you are right. The s5 transmissions have a dynamic damper in the back section when you take off the extension housing/tailshaft. The s4's don't, I wasn't sure if that had to be swapped over to the s4 transmission from the s5 one I had taken out or not so I did not swap it over and put the s4 transmission in without it. I had originally done the extension housing/tailshaft swap because I didn't want to spend money on a s4 crossmember when I had everything for it to work as an s5. I'm going to have to look through that and see what I can find but believe me I have been searching A LOT.

I read through the link and it doesn't say whether or not I needed to put the rear counterweight from the s5 onto the s4 transmission so I posted a question. Hopefully someone on here will chime in. I figure I'll help narrow down my problem by removing the driveshaft and starting the car to see if there is still a vibration or not.

Ya,..the thing about the counterweight just rang a bell when I read this thread,so I thought I would mention it.
Honestly I don't go "that far" when the trans is screwed, I get another one.

I did get another one because my original s5 transmission had cracked around the shifter fork/slave area and was very hard to get into first and reverse but the one I got was from an s4 and I have an s5 Vert and me not realizing the mounting differences put the s4 transmission in then realized the differences so I figured a simple solution would be to just swap tailshafts to use the s5 mounts and crossmember but after swapping tailshafts I lost reverse and 5th and I had both gears before the tailshaft swap. The vibration I keep talking about never happened to me before until I put the s4 transmission in. It was happening even before swapping tailshafts. I have a few options I can try, one being to just put the old s5 transmission back in and deal with it until I can get an s5 transmission I know works and just sell the s4 transmission cheap.

Im in the same situation with my s5 vert i need a trans due to bearing noises and got an s4 cheap...but from my searching on here i assumed all you had to do was swap the crossmember ..i just got one on here for 30$ shipped.. i hope thats the only difference in the two trans and i dont have to swap tail shafts...

did you ever swap them back and see if you get the gears back?

That would have been the easiest thing to do ,Change the cross member.It doesn't involve any crucial parts being switched.Maybe a little wiring.

I know how it is though when you are in a pinch and want stuff working and want it now.The thing is the car doesn't Care.It wants it done right.

All you have to do is swap crossmembers but I was strapped for cash at the time and wanted it done without having to wait for shipping because my FC was my daily driver at the time this happened. I did not swap the tailshaft back I figure it was the way I had set the shifter control rod in the gears or someone told me to look to see if I forgot the washer on the reverse lights sender switch because they forgot it and lost the same gears as me.

1. the S5 has the big damper thing, the S4 doesn't. even if you could swap that over, you don't need too.

2. if your "new" trans was used, it is possibly bad too.

3. it would be hard to bend the driveshaft, although i'm sure someone here has done it. more likely there is a bad u joint

4. you need to make sure the shifter works on the floor before you put the transmission in the car, it IS possible to miss a shift finger or screw other stuff up, i've actually done this same thing, but we caught it before it went in the car, because i checked it before i put it in the car. live and learn i guess.

Yeah it was more of I only had the FC to drive at the time and being that I had every part to make it work I figured it would go over with no problems since I was following the FSM. I really think me losing gears was due to missing the washer on the reverse lights sender because I did change them but I did not check that out yet. Reason I think that is because earlier in this thread another member said they had the same thing happen due to that washer missing. All the plugs are the same for s4 and s5 transmissions to the harness, I only had to crimp 2 wires together that were already previously crimped together since day 1 when I had bought the car as a shell with trans.

Thank you for clarifying that I did not need to swap the dynamic damper/counter weight over. I was wondering if that missing was causing the vibration so now I can rule that out completely. I'm really thinking that the new used s4 transmission I got was bad, the guy I got it from lacked a lot of information on it and didn't say much but luckily I didn't lose out too bad if it turns out the transmission is bad. My driveshaft worked great with the s5 transmission (no bad u-joints) so I don't see how it would've gotten bent either unless someone did something with it while it was out and I wasn't in my garage since I have to share the garage. I did try shifting through the gears with the transmission on the floor but only used 1 bolt to hold the shifter down just to check it quick and it felt like all gears were there. I have to pull the transmission back out anyway so it really is no big deal, I've done it enough times already that it shouldn't take me that long to do. I definitely have learned a lot from this experience.

I'll second this. I have an S5 transmission with an S4 extension housing in my car, but I made sure to try all of gears before bolting it up the the engine. Unfortunately, I think you'll have to pull it and remove the housing to see what's going on.

Yeah basically the same thing but I have an s4 transmission with s5 extension housing. I did try the gears but I guess I rushed it and mistook 3rd as 5th somehow. Oh well, I planned on pulling the transmission out anyway because I'm pretty sure it's no good. As of right now I plan to pull the s4 transmission back out, take the s5 extension housing off, and re-install it on the s5 transmission and put the s5 transmission back in the car until I find a legit working s5 transmission. The s5 transmission was taken out due to it being hard to get into first and reverse but after taking the transmission out and finding a washer and 2 other very small pieces of metal stuck behind the pilot bearing I think that my have been my problem but maybe not too. That's what I get for having someone who is lazy and who likes to half ass things put my transmission in when Im not home. Im looking at doing this over the weekend but there is so much snow and ice out on the roads I don't even want to the take the FC out.

Detent springs and balls are important. Not something to just "Its binding, let me just leave it out"

You may not find out what that spring and ball was for till after you get it in the car and apply power and pop, out of gear it comes. Transmissions in general can be touchy, everything has a place and space, if any of its missing, it may not go in gear or it may not stay in gear or worse.

I only left the ball out, not the spring too. I asked for tips on how to get the ball to stay put without jamming the other spring and bolt and got no responses. I tried finding a way but every time I tried the entire shifter would jam up from the ball being jammed in the other spring/bolt. Either way it really doesn't matter because there is obviously something seriously wrong with the transmission and there has been since I bought it. It just sucks that you cannot trust anyone when dealing with parts. The guy obviously ripped me off by not telling me the transmission whines really loudly while in gear and I never had a bad rpm related vibration problem until I put this transmission in. I learned from it and I'm not making the same mistake twice.

I have kept up with this thread but haven't posted as I can't offer any info. However, I have been wondering, based on your observations, if the previous owner dropped the trans or extension housing and bent it. Granted it would be unlikely as it would normally crack, but I have seen weirder shit.

I have a s5 tranny in my s4, bolted up like its spose to be there.
It does have all s5 crossmembers under it tho. you guys work to hard

It's possible but I doubt it. When I bought my car the transmission and rest of the drivetrain was installed and looked like the crossmember had never been unbolted before.