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Lost 5th and REV ???? Is this a common trans failure?

11489 Views 8 Replies 5 Participants Last post by  mrgrayaz
98 frontier 2.4l 5spd manual 216k miles
I know that transmissions are not supose to fail as a common occurance, but of the failures on 5 speed transmissions is this common? I was driving to work and it acted like it just popped out of gear, so I reach up to put it back in gear and it is already there. I drop it down to 4th and I'm good to get to work. I leave to get some lunch and Reverse is gone as well. The trans did not make any noises, grinding or anything when this happened or while driving the rest of the way to work. If I am stopped and put it in 5th or Rev I can hear just a little grinding noise, but not bad. I plan to drop the fluid today to see how shiny it is. I also felt the trans and it was normal temperature when I got home. 40 miles each way. I have rebuilt many ford T5 transmissions and was wanting to get some info on this one before I break it open.

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i had a similar problem years ago back when i was driving a mitsubishi eclipse i was just driving on the highway and it just popped out of 5th then didn't do it for a while then pop. i figured out that it wouldn't pop out till the tranny started to get up to temp, not high temp but normal temp, i stopped using 5th in the city and on the highway i literally held it in gear lol. i could feel it forcing against my hand the more gas i gave it. so i did some research about it and everything i found was saying saying a synchronizer is almost certainly the culprit. The synchronizer is a bronze helitical cut gear that is positioned in front of a drive gear. Every gear except reverse has one and its primary purpose is to line up the teeth of the gear you are in with the next gear up or down. The gears are cut at an angle so when they are aligned at different speeds of rotation they will be able to mesh. Now, the second function of the synchronizer is to keep the car in its selected gear. Because the gears are helitical "teeth cut at an angle" the direction the angle faces can have a dramatic effect on how the gear reacts. The gear is designed to act in a way that when you engage it the rotation of the gear and the direction of the teeth force it to disengage. If it were the other way around the disengagement of gears would be next to impossible at any speed. This is where the second function of the synchronizer comes into play. It prevents the gear from backing out of gear unless the clutch is engaged and there is no load on that gear. So, your synchronizer is internally worn and is no longer tight enough to prevent the gear from slipping out at or above a certain load or RPM. You can probably drain the tranny to get any metal shavings out and continue to drive it as a 4 speed with no problems. The worst that will happen is lower fuel economy at higher speeds on the highway. You can certainly do it yourself with a good shop manual if you are handy with a wrench. Since you have rebuilt some T5s i'm sure you know what a synchronizer is but thats just a little more background and insight on something you may or may not know about them. hope this helps
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I had a basic understanding of how they worked, but now I have an even better one. Thanks......The only thing that makes me question the synchronizer is that it never ground any gears when shifting into any gear and seemed like a tight transmission. The gear shifter phyiscally goes into 5th or rev and stays in place when the clutch is released. I can feel the shift forks moving the gears like everything is still intacted inside. The only way I know there is a problem is the engine just revs when you hit the gas, or the engine does not slow me down when the gas is not pressed. It is like the splines on the shaft or the splines on the inside of the 5th/rev gears are stripped.
oh got ya, yeah mine was a bit different than that, i could watch it push the stick out of gear and could feel it pushing against me when i held it inplace untill i ripped it apart and changed that synchronizer. it never seemed to grind at all for me. but if your gear selector (stick) is in the 5th gear pos and stays there but the engine just revs up then yeah i'd say its different than my situation. when you drain it i would see if you can identify what type of metal if any is in the fluid. for me it was easy to see that it was bronze in the fluid cause my fluid had a very gold colored shimmer to it. if its more silver colored than that would definitely point to something other than the synchronizer since those are generally made of bronze. is that tranny a rod shift or cable, cause if its cable there could be a possibility of a cable being out of adjustment or maybe stretching and not fully engaging the gear sometimes.....
I was hoping for the cable system too, but it looks like the stick goes into the ball and socket system to move the shift forks.
well thats crappy lol, i guess your best bet is going to be giving it a drain and see what comes out
Mine did this. 98 4x4 4cylinder. it was making a gear noise in all gears but 4th. Then right before I parked it to check it out, it lost 1,2,3,5,and R. I drove itin 4th only for a day. that was fun. still searching for info on buying, rebuilding this.
^^You should be able to find a rebuild pretty easily as i have for just under 300 for my 4banger HB.But also had a couple of talons with the trans grinding,and eventually it grinds the blocker ring/synchronizer all the way down not allowing the selector to allow it to stay in gear.But as far as loosing 5th and rev it sounds like a possible bent shift fork.

Sonds like the shift fork may have finally snapped or cracked which is probably why you can move it to the gear position but not actually in gear.Also it moves the selector just enough to barely touch thus a faint grinding noise,you may just be able to get a new shift fork thus you dont have any other trans problems.
Rebuild it now, you might be able to save the tranny. wait too long and you will just have to junk it and get a new(or used) one.
You'll lose 4th next, and then 3rd. its kinda cool how they fail.
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