Shifting issue

[PhillipM]

I have a toploader WR with about 420 miles on the car. It runs great and I went for a 40 mile ride today. When I leave the driveway it shifts fine and is butter smooth all gears. However, about 15 or so miles into a trip it become very difficult to shift. Mainly when I come to a red light and have to down shift. There was a time when I could not get into 1st gear and had to leave in second. I have checked the oil and it was fine. Could I have a synchronization issue? OR a linkage problem? Down-shifting is more difficult than up-shifting.

Also, when I arrive home after a drive it goes into reverse fine.

Thanks in advance for the advice

Phillip

[RJacobsen]

bad syncros would probably result in some grinding, sounds like a linkage adjustment problem. Is your clutch fully disengageing?

[Tony Radford]

I would lean more towards the clutch issue myself. I have the same tranny and the only times I've ever had shifting issues was when my clutch wasn't fully disengaging. That also explains the change in performance after you've been out driving for a while. A small amount of air in the lines will prove problematic, but it could simply be that an adjustment is in order. You will find countless posts on this forum regarding clutch performance. Assuming you're using the external push-type slave, it can take a fair amount of "fiddling" to get it right and I have the scars to prove it.

[rosco]

I had a similar problem with my close ratio toploader; come to find out, using a synthetic lube (Joe Gibbs) vs. normal was the cause... I changed back to the traditional lube (valvoline 80w90) it now it is fine.

I just seem to have transmission leaks even after I replaced a rear (transmission) seal...

Gino

[rldunn7]

Me thinks you have the boiling brake fluid in the clutch system problem...If you push the clutch a couple of times it will probably shift... You see, on the back of the brake fluid can, "what is called" the "wet boiling point"... that is the temperature where the water that accumulates in brake fluid(A natural occurence) and the brake fluid tend to boil. It happened to me several times until I figured out the problem... you are sitting there pressing as hard as you can and the darn thing won't shift....well you need that thirty thousandths clearance or so between the clutch and the flywheel to make it happen.... that boiling mixture of water and brake fluid just Squishes together and does not give you much push....Get some racing brake fluid with a HIGH boiling point and try to locate the line going to the clutch slave cylinder as far away from the headers as possible.... good luck, took me a while to figure this out!!! Also, change the fluid in the slave cylinder at least every year and if you check the fluid often change it every 6 months....also take the nipple off the slave cylinder and let any fluid out of it....if you don't it will cause an accumulation of water(remember the brake fluid is a water getter) and the iron will rust beyond belief!!!!

Been there and got the spare slave cylinder in the trailer and have fixed mine in the parking lot in Pigeon Forge and driven through the mountains back to the hotel with no clutch...NOT FUN...but got the tee shirt and the tattoo!!!!!

[rldunn7]

DO NOT USE synthetic lube in a toploader....talked to my drag racing buddy and he never had a failure in a toploader till they went to synthetic lube....then blew the bottom out of two transmissions....went back to good old nasty smelling 80W lube and have not had a failure since!!!! just my opinion and some practical knowledge....

[JeepSnake]

Agreed with Richard.

Get some of the aluminized insulation for your clutch line. Reroute as needed to get it away from the headers. Use Wilwood 570 degree racing brake fluid.

If you're running the Wagner or Lockheed slave, adjust the pedal up as well. That slave can apparently handle extra throw in the pedal and master. This can give you a little safety factor if things heat up. Do NOT do this with any of the hydraulic throwout bearings, as you'll wreck them with too much master cylinder stroke.

[rldunn7]

Remember that the slave cylinders are CAST IRON and do not have any type of brass sleeve in them... Remember here that the water that accumulates in the slave cylinder will fall out of solution and puddle along the bottom of the slave cylinder....IT WILL CAUSE IT TO RUST!!!

Over time you will have a nice rusty path for the slave to blow fluid by(then you can replace it)!!!! That is the reason for changing the fluid so often. You will see this if you bleed the slave and see the rusty orange colored fluid..... good luck and believe me I have seen all this stuff way too upclose and personal!!!!

Also, be aware of the tension that you have in the spring for the clutch arm....If it is too strong it can cause the neoprene on the plunger to beat itself to death against the end of the slave cylinder...

[PhillipM]

Thanks everyone for the advice. I will re-bleed the system this week to make sure there is no air in the line. I will also check the throw to make sure I am getting enough travel at the clutch. I will also insulate the line since at one spot it is about 1in from the #4 header tube. If I see no improvement, then I will look at the linkage.

:Setup:
In the toploader I am running conventional gear oil (Valvoline 80W-90), never plan to run synthetic. For brake fluid I am running Wilwood 600 plus.

Thanks
Phillip

[arrowdriver]

Which slave cylinder is recommended for use with a 427SO and toploader? My master cylinder is a Girling that Alan installed way back when. I overhauled it this spring and the walls looked good but the slave is weeping a bit and I seem to have the same kind of problem as mentioned here so plan to change the slave for a new one, and would greatly appreciate some advice on what to use and where to get it.

[arrowdriver]

So can anyone advise how long a travel is needed on the slave cylinder to release the clutch? I measure mine at 1.5 inches, measured at the end of the throwout arm, which seems excessive. I am wondering if I have an internal problem with the clutch but before puling the tranny figured I would fire the question out here.

[Jim Harding]

I don't think many slave cylinders will go over an inch... maybe some a tad more, but not an inch and a half. My clutch will completely disengage with less than an inch of movement of the clutch fork. (measured at the point where the fork and slave rod meet, which translates into less than an inch travel of the slave cylinder.

I have two part numbers for the slave cylinder. Physically they are the same:

Wagner SC12411 F124111

Raybestos SC33721 233721

[arrowdriver]

Thanks Jim.

Does anyone have any ideas on what could be the cause of this need for such a long stroke on the lever end of the fork? I didn't build this car and only have owned it for just over a year. The 427 engine seems very good once I got the timing and valve lash set right. From what I can tell it only had about 2500 miles on it since it was installed in 1991 and I have only added another 1500 to that. Bringing a new Unique into Canada was a none starter due to Transport Canada but fortunately the loophole regarding "antique" cars over 15 years old allowed me to find an "old' one and circumvent them. Only issue now is the clutch drags.

The slave cylinder installed when I got the car was a 1 inch dia that I see in other' s pictures here, the one with the single mounting arm with two bolt holes. It had been directly bolted to the engine by someone who filed one of the holes out to increase the spacing a bit so it matched that of the tapped holes in the block. This caused the push rod to be at an extreme angle. I made up an adapter bracket to more closely align it with the arm so eliminated the angle. This cylinder was missing it's dirt boot and was leaking due to some corrosion so I bought an identical one from NAPA. I noted that the rod had been adjusted so that there was some pressure on it even when the cylinder was fully retracted, something that concerned me since it seemed likely to cause a lot of wear on the throwout bearing. I then bought a 3/4 dia slave and tried to get the needed travel to both get full release and not have the bearing dragging when retracted. This 3/4 one seemed to do that for a while but then noted that when the engine was hot after driving for a while it started to drag. Went through the excercise of bleeding and got no air so figured that wasn't the problem.

I then measured the needed travel on the arm to get full release of the clutch and at the other extreme get no dragging of the throwout bearing. This is about 1.5 inches which seems excessive.

My guesses are that one of the arms of the clutch are bent or the adjustment bolts on them has come loose, but sure would like to hear of other' thoughts on this before I go pull the transmission to get to it. The scatter shield type bellhousing doesn't give me much of a view inside.

By the way, it looks like pulling the transmission is best done from below allowing the engine to stay in place. Any suggestions or shortcuts greatly appreciated. I have seen a lot worse cars to work on. Most of the big auto makers could learn a bit from Unique in designing a car to be able to be worked on.

[Jim Harding]

My guesses are that one of the arms of the clutch are bent or the adjustment bolts on them has come loose, but sure would like to hear of other' thoughts on this before I go pull the transmission to get to it. The scatter shield type bell housing doesn't give me much of a view inside.
By the way, it looks like pulling the transmission is best done from below allowing the engine to stay in place. Any suggestions or shortcuts greatly appreciated. I have seen a lot worse cars to work on. Most of the big auto makers could learn a bit from Unique in designing a car to be able to be worked on.[/QUOTE]

I'm lost when you mention 'adjustment bolts' being loose. The only adjustment I'm aware of is the overall length of the push rod between the slave and fork. This rod is usually threaded and can be adjusted for proper length. There are bolts that support the fork pivot inside the bell housing, but they should be very easy to check.
My procedure for adjusting the length of the push rod is as follows. First disconnect any return spring from the fork to allow free movement back and forth. Move the fork backward toward the rear of the car until the throw out bearing touches the clutch release springs. Adjust the length of the push rod so that it just touches the contact point on the fork. (make sure that the slave piston is completely pushed into the cylinder). Then back off the push rod adjustment one turn. Reconnect the return spring and try it. If you still get some drag between the bearing and clutch, back it off another round. Also, have someone else push the clutch while you observe the slave cylinder. A poor mounting arrangement might cause some movement of the slave, and this will result in less travel of the fork.
As you said, an inch and a half is extreme. With my car, a one inch slave and 3/4 master just didn't give me enough travel to completely disengage the clutch. I went to a one inch master and my problem is now history. The down side is a heavy clutch, but I can live with that. Perhaps a 7/8 master would have been a better choice, as others have found, but I didn't want to try a "hit and miss" approach, so went right to the one inch. And as I mentioned before, I have proper 'free play' and complete disengagement at just under and inch of travel.
As far as pulling the tranny, you will have to remove the shifter handle, and maybe the linkage too. Remove the drive shaft and seal up the rear of the tranny with a plastic bag and tape to prevent fluid from leaking out. If you're lucky enough to have a proper plug, use it ;)
Support the rear of the engine. When you take out the transmission cross member, you don't want to leave the engine hanging only on it engine mounts.
Remove the cross member.
And here's another hint. Remove one of the transmission bolts from the bell housing and head up to your nearest hardware store. Get TWO bolts with the same thread type, but about three inches longer. Go back home and cut the hex head off the end of the bolts. File or grind a nice radius on the end. What you have now are some studs that you can place in the bell housing to let you easily move the transmission back and out without hanging up the input shaft in the clutch release springs. Makes putting it back in easier too.
Keep us posted on your findings.

[arrowdriver]

Jim, thanks again for the helpful advice. This is pretty much what I figured but it is nice to confirm it before turning the wrenches. The extension bolts are a good idea.

The "adjustment" bolts I was thinking of are the ones at the ends of the clutch fingers that one adjusts to make sure all arms contact the throwout bearing simultaneously. The symptoms seem to suggest that for some reason at least one of the arms is late in contacting the throwout bearing whether this might be because the arm is bent, the adjustment bolt has turned or whatever. For sure when I get time to pull the clutch and find out what has gone wrong I'll post here in case someone else encounters the same thing.

[arrowdriver]

I promised to post what I found when I pulled the transmission etc. This is in relation to my clutch dragging and the throwout fork having to travel an excessive amount to get full release. Anyhow, the problem was caused by two of the three bolts that hold the pivots for the arms coming loose and backing out, one of them quite a bit. The clutch lining and faces all look really good yet and the actual action was smooth, no chatter etc. so I'm probably going to just Loctite those bolts and reassemble the whole works. I'll put a dial indicator on the clutch to confirm that the arms are all the same length and not bent. The throwout bearing feels a bit rough so a new one will go in but from what I can see, that is all I need to replace.

By the way, is there a boot available that fits the fork when you have a scatter shield type bell housing? It's not that I drive on a lot of dirt roads but figure that regardless if this is something available I'll get one.

[Jim Harding]

Glad to hear you found your problem and won't have to bare any great expense..... except maybe your sweat and labor ;)
Drive safe.

[arrowdriver]

I'm planning to change the starter to a permanent magnet type as the one I have cranks just fine when the engine is cold but struggles when it is hot. Anyone else done this? If so, what improvement did you get and was it worth it?

[arrowdriver]

Well the weather finally cleared up and with the roads being dry I took the Cobra for a drive yesterday. Success! It has never shifted so nice since I have owned it. I left the smaller slave cylinder installed and though the pedal pressure is a bit higher it isn't so much as to be difficult and when driving one doesn't even notice it, just that it takes a very short travel to disengage. By the way the master and slave are the same size bore.

Thanks to those who offered adivce, it all helps.

[Slither]

Thanks everyone for the advice. I will re-bleed the system this week to make sure there is no air in the line. I will also check the throw to make sure I am getting enough travel at the clutch. I will also insulate the line since at one spot it is about 1in from the #4 header tube. If I see no improvement, then I will look at the linkage.

:Setup:
In the toploader I am running conventional gear oil (Valvoline 80W-90), never plan to run synthetic. For brake fluid I am running Wilwood 600 plus.

Thanks
Phillip


How did you finally make out with the fix?