Trouble selecting 1st and 2nd gear when warm

My '63 SIIA has developed and interesting issue. After driving for a while I cannot select 1st and 2nd gear while the car is stopped (engine running). No grinding, just the gear lever refusing to get into these two gears. I can select 3rd, release the clutch momentarily and then shift to 1st and that works ok. Interestingly enough, I have no problem shifting into 1st or 2nd for the first few minutes I drive the truck so something happens when everything warms up (which is somewhat counterintuitive).

Any thoughts as to what may be going on?

Thank you
Vangelis

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Originally Posted by vangk

my '63 siia has developed and interesting issue. After driving for a while i cannot select 1st and 2nd gear while the car is stopped (engine running). No grinding, just the gear lever refusing to get into these two gears. I can select 3rd, release the clutch momentarily and then shift to 1st and that works ok. Interestingly enough, i have no problem shifting into 1st or 2nd for the first few minutes i drive the truck so something happens when everything warms up (which is somewhat counterintuitive).

Any thoughts as to what may be going on?

Thank you
vangelis

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hi
i suggest u see how well your clutch is disengaging....which i suspect could b your issue. The release lever arm under the truck should rest in a horizontal position [parallel to the ground at rest] and go down maybe 1/2- 5/8" with pedal depressed. Those early systems could b dicey sometimes. R u using dot 4 hydraulic fluid?? U could have either a leaking master or slave cylinder

good luck,


dare

Assuming - that your Series has a hydraulic clutch(?)
1. Check hyd clutch fluid level
2. Either the slave cylinder or the master cylinder may be leaking oil past the seal, thereby preventing the clutch from fully disengaging. Difficult to diagnose. Replace may be best option.
3. The hose from the master cyl to the slave cyl might be old, and as oil temp rises (or if it is routed near to the exhaust manifold), the hose expands, and the internal diameter gets smaller - thereby restricting flow to the slave cyl, thereby preventing the clutch from releasing completely. This would effectively 'block out' the dog clutches for 1st and 2nd gear from engaging into the mainshaft gear. No synchro on those gears, so blocked out is blocked out.
In 3rd, you have the synchro helping things, so it engages - with no grinding? Synchros help here, but the system still isn't working correctly - 3rd and 4th gear synchros will wear more rapidly. Recommend replacing the clutch hose.
4. New fluid. Bleed system per manual.
5. And, if it's manual clutch, adjust/increase the clutch throwout per the manual.
my 2 cents.
Dave
1970 Series under the knife

Thank you both, I'll take a closer look over the weekend. The clutch and both the slave and master are relatively new (within the last couple of months). I don't remember if the hose was changed at the time as well.

a dragging clutch gets my first vote!