Godawful shaking in reverse

[TaurusPimpin]

Another issue has come up with the MTX Vulcan. I drove up to UT tonight for classes, and I went to park. The spot I went for was on a bit of an incline. When I went to back up, it was very hard to get into reverse, and the car shook horribly, and would not want to go; No matter how much clutch or throttle I gave it, it wouldn't get better, but the engine would not stall; I had it up to the redline without realizing it, since I was looking where I was expecting to be backing up!:cry: I feel pretty lucking that I don't seem to have hurt my engine.

It did this repeatedly; part of the way I got it back up the incline was to feather the clutch on off, on off, and it would go a little before it started to shake, the other part was just bearing it, which made me feel terrible for doing that to my car. The shaking is very, very violent; I'm pretty sure people walking by thought I was crazy, but of course no one offered to help.

It never has this problem in the forward gears. Shifting is pretty easy, except second is notchy sometimes, but I never have trouble getting it in. My gut makes me think it's something like it's not fully engaging, and then when torque is applied, it tries to disengage. It doesn't always do it either, but it has done it since I got the project done; I just thought I was bad at using the clutch. Any ideas? I'm afraid to park anywhere where I might have to back up now.

 

[TaurusPimpin]

To add a little more to this, I did some backing up today, and it seems that when I can tell it hasn't engaged reverse, if I slowly let the clutch out and keep pressure on the shifter, once I reach a point on the clutch (well before the friction point) it will go all the way in. Is this normal behavior, given that reverse doesn't have a synchro? I'm thinking what happened to me last night was this same sort of deal, and I was just stupid and didn't realize it.

 

[Kens1992mtxSHO]

Try putting it in second gear then into reverse. This is a common thing with the SHO which usually results in a little grinding.

 

[dantheman68]

Check the passenger axel... mine did this after the support bearing came a bit loose from the block...

Or else it could be a failed rear motor mount, these were the exact symptoms I had when my MM was bad... with the first suggestion of mine, you should also notice it a bit in first gear (i did atleast)


It sounds like its more like the second (bad motor mount), since a bad rear mm will also cause poor gear engagement.

when driving forward, and you depress the clutch semi quickly, does the car seem to shake or stutter a bit more than usuall?... mine did this when my rear motor mount was bad, but if it doesn't, i still have my money on the motor mount

to test the MM, lift the hood and engage reverse with the e-brake, or the rear wheels blocked... then try and move the car (it shouldnt, since you have the rear wheels stopped, if the engine is moving alot, your motor mount is bad.

 

[Kens1992mtxSHO]

Check the passenger axel... mine did this after the support bearing came a bit loose from the block...

Or else it could be a failed rear motor mount


It sounds like its more like the second (bad motor mount), since a bad rear mm will also cause poor gear engagement.

when driving forward, and you depress the clutch semi quickly, does the car seem to shake or stutter a bit more than usuall?... mine did this when my rear motor mount was bad.

...and what he said

 

[TaurusPimpin]

I'll definitely check my intermediate shaft support; I'm waiting for the car to cool some before I get under it. Both my motor mounts were replaced when I did the swap; both are new and previously unused. I'll check them too, though. No problems or shaking in any forward gears. I did try putting it into fifth before reverse, since I thought 5 and R are on the same countershaft, but not second. Thanks for the advise!

 

[Kens1992mtxSHO]

Hope it works out.

 

[TaurusPimpin]

One thing I found was that the nut on the rear engine mount was somewhat loose. Don't know if this could be cause or effect, though. Other than that, my whole exhaust was rattled loose.

 

[38SHO]

sometimes my car doesn't like reverse either...

but on the slight occasssion it acts up on me, yes letting off the clutch pedal slightly and it goes right in..... its nothing bad.....

possibly your not slipping your clutch enough when moving backwards.....

 

[TaurusPimpin]

No, I know It wasn't a clutch/throttle issue; Felt different, and if I pushed down on the clutch pedal, it didn't get better. I think I'm going to tighten everything up, make sure my motor mounts and intermediate shaft are ok, and just chock it up to me being an idiot. I'll drain the tranny fluid as well, to look for any shavings to see if there is any definite damage.

 

[TaurusPimpin]

Well, I went to tighten up the MM this morning, and to my surprise, the stud pulled out of the bottom of the mount! The front mount seems like it's ok,though. I torqued the nut on it to 70 ft-lb. Looks like I'm off to Autozone to get another on warranty.

 

[TaurusPimpin]

All right, I have to bring this back up. It did it again today, but I was lucky enough to have a couple of people stop and help me push the car. I don't get it; the engine is not stalling, it's not grinding, at leas that I can hear or feel, it just bucks really bad in reverse. I can back up on a flat surface very slowly, and it will be ok, but on any type of incline, it just will not do it. I know it's all the way in gear; I held a foot on the break, and eased the clutch out until the engine started stalling, while pulling back on the shifter. Does anyone have any ideas about this? Fluid is brand new Mobil 1, all other gears are fine. The car drives wonderfully going forward, but I can't be safe driving it all the time with this reverse problem.

 

[TaurusPimpin]

Ok, here is what I have observed; the car will back up fine as long as I let the clutch slip a lot. As soon as i give it a little more, no matter how much throttle it has or what the engine speed is, it will start this bucking. This is why I can't back up hills; it needs more clutch to get the power to do it, and when starting facing down a hill, I let the clutch out too fast too much, to avoid rolling down the hill. There's a sort of golden clutch point, but this only happens in reverse; starting in first is no problem on any hill. Is this normal behavior for these trannies, or is there potentially something wrong with reverse for me?

One thing I haven't checked is the subframe bolts, but I would think that an issue there would also result in sterring issues, and problems moving forward as well. I have ALSFB's, and the bolts are torqued to 100 ft-lbs, per the advice of others with ALSFB's.

 

[Kens1992mtxSHO]

I know my car doesn't do this in reverse and I don't know that this is a common issue.

 

[TaurusPimpin]

That's what I figured; I'd like to try to narrow it down to a specific issue before I pull the tranny again. The car is OK to drive as long as I'm careful about where I park, and make sure it's either flat or I can pull out going forward. I do have a second tranny, out of a '95 (the one I used for the conversion is out of a '93, but has 15k on a rebuild), so if it is a real internal problem, I can probably use that one for spare parts, if that is necessary.