Tranny Problem…no forward gear but reverse works

Topics Last Day Last Week Tree View    Getting Started Formatting Troubleshooting Program Credits    New Messages Keyword Search Contact Moderators Edit Profile Administration
Model T Ford Forum: Forum 2012: Tranny Problem…no forward gear but reverse works
Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Reif on Monday, October 29, 2012 - 12:10 pm:

Has anyone ever encountered a transmission problem where you have no forward gear (high or low) but reverse still works? I just encountered this problem with my ’26 Roadster over the weekend and I am at a loss as to how this is physically possible?!?! I’ll cut to the chase and say that the problem was corrected “slamming” the clutch (emergency brake lever) a couple of times. After that…whatever the problem was, it was corrected and the car drives perfectly fine again.

I’ll provide some characteristics of the problem below but, to set up the problem, the car did set for over a month while I removed the gas tank to repair a leak. While sitting in the garage, I had the emergency brake forward (clutch engaged), which might have enabled the problem. Prior to removing the leaky gas tank, the car ran great and I’ve never had a significant transmission problem. This transmission was installed back in the ‘60s but it hasn’t been routinely driven so I’m guessing that I probably have around 10K miles on this transmission.

TRANSMISSION FAILURE CHARACTERISTICS
-No forward gear as Low & High gear will not engage.
-Removed inspection plate to verify drums were engaging properly (while running) and clutch clevis “appeared” to be properly engaging the driven plate.
-Reverse gear engages properly and will move the car.
-Engaging the brake places a load on the motor and would kill it.
-When increasing the RPM, above idle, a very noticeable vibration occurred in the transmission.
-Other than the vibration, no horrible noises (e.g. gear grinding) were noticeable.
-Oil was drained and no debris was found in the oil…praise the Lord!

CORRECTIVE ACTION?
-Slammed the emergency brake forward, multiple times.
-I’m theorizing that this enabled the clutch to properly engage and/or align. However, I can not explain why I would have reverse but no forward gear if the clutch was somehow misaligned???
-Drove the car, about a mile, and it now drives fine with no apparent problems.

Let me know if anyone understands what happened to cause this tranny problem. It would seem that I don’t have a significant problem but I would like to better understand what caused this failure so I don’t have to worry about having a catastrophic failure later down the road. Thanks, in advance, for your insight!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Monday, October 29, 2012 - 04:51 pm:

The clutch engaging only gives high gear. The clutch MUST disengage for either low or reverse to work. The odd thing is that you didn't have low, but reverse worked. It is not rare to have the clutch mechanism hang up and lose high, but usually both low and reverse will work. It could be possible for the pedal/handle linkage to be badly adjusted and cause it to bind the low pedal at the same time as the clutch is held out.
That would be my first guess.
All that adjustment is a bit complicated, really quite simple, and very forgiving of poor adjustment.
First posting? New to Ts? Welcome to the affliction! This is the best place for questions if you want answers or a good discussion.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Reif on Monday, October 29, 2012 - 08:31 pm:

Thanks for the reply! I am familiar with the free neutral adjustment that you're referencing. For the life of me, I can't understand why I had reverse and no forward low??? I'm assuming that the clutch was somehow jammed thus disengaging high gear. But Low & Reverse both use the same driven gear that turns the brake drum. All I can think of is that it must have something to do with the clutches (or push ring) possibly binding to the brake drum??? I was hoping someone possibly ran across the same crazy problem that I just experienced.

I have posted a couple of times, on different topics, but nothing lately. The '26 Roadster was originally purchased new by my Grandfather so I've been around this T pretty much all my 40+ years. I also have a '27 Touring that I'm putting together...when I have time. The more I work on 'em the more I learn about 'em. ;)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Reif on Monday, October 29, 2012 - 09:15 pm:

Correction...My Dad and I are putting together the 27 Touring. Gotta give credit to the Boss too!!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Reif on Thursday, November 01, 2012 - 09:29 am:

Where's our resident Model T transmission Guru??? Let me know if anyone has a best guess as to what might have caused my transmission problem. Thanks!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Thursday, November 01, 2012 - 10:34 am:

Sounds like the link between the low pedal and the clutch went over center which is the only thing that could explain all the symptoms. Likely the hole in the link adjuster or the hole in the clutch arm or both are worn significantly, combined with the clutch being adjusted too loose.

Bottom line you need to check clutch / low pedal adjustment. Takes a good 2 - 3 minutes. Have you got a copy of the factory shop manual? It has great pictures and instructions for the novice T owner.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Reif on Thursday, November 01, 2012 - 04:14 pm:

Thanks Royce! I'm positive that the adjustment was not the problem as I have a very good free neutral/clutch adjustment and the external linkage was moving freely. I also removed the inspection cover and was able to view the clutch clevis moving freely with pressure being applied to (and removed from) the clutch fingers.

The main question that is driving me crazy is...How can you have reverse BUT no forward gear (High or Low)?

I'm willing to give up on the why the brake was killing the engine as that was obviously related to the dysfunctional clutch. However, if the clutch was dragging inside the brake drum, wouldn't I have a direct linkage to the drive line???

I have successfully rebuilt a Model T transmission in my other '27 Touring. I wouldn't dare claim to be an expert but I wouldn't consider myself a novice either. ;-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kenny Edmondson, Indianapolis on Thursday, November 01, 2012 - 04:38 pm:

The brakes being able to put a load on the engine or kill it tells me the problem isn't in the transmission. Reverse works and direct (high) must be working to be able to have an effect on the engine. The noise could be anywhere in the drive train. The input shaft is bolted to the crankshaft and the high speed clutch hub is bolted to the other end. If the clutch wasn't engaging the brake wouldn't have an effect on the engine. You've got an issue after the transmission.

u-joint - probably not, but possible

pinion gear key sheared and pinion slipping on the driveshaft - very possible

Thrust washers in rear axle - maybe

With the trans in high, parking brake released and engine off, see how far the car will roll before the engine starts to turn. Roll it both directions and measure the total distance.


Top of pagePrevious messageNext messageBottom of page Link to this message  By R. S. Cruickshank on Thursday, November 01, 2012 - 08:17 pm:

I assume you are testing with the rear wheels off the ground. That said, I think one possible cause, although many would doubt, is the drive shaft it broken and will wedge together for reverse but slips in forward. I had the shaft break inside the rear pressed on race. It caused similar results.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Reif on Saturday, November 03, 2012 - 11:55 am:

Earlier this week, I took the car out for another 2 mile drive and it drove perfectly. Whatever the problem was, it no longer appears to be an issue. It obviously had something to do with the clutch but I'm certainly stumped as to what the heck actually happened?!?!

I greatly appreciate everyone's response to this thread but I guess I'll just file this one away as another interesting Model T quirk???


Posting is currently disabled in this topic. Contact your discussion moderator for more information.
Topics Last Day Last Week Tree View    Getting Started Formatting Troubleshooting Program Credits    New Messages Keyword Search Contact Moderators Edit Profile Administration