Series IV Tranny questions

[Chasedan]

Hello All,
I am currently working on a my Series IV transmission rebuild.
My first question:
My gearbox is nearly all apart however I am not sure how to remove the output (driven )shaft from the gearbox. The manual says that the output shaft is easily removed through the front gearbox opening after the circlip is removed from the rear bearing and the shaft, gears and bearing assembly are driven foward into the gearbox and out of the front opening. My current predicament is that the first gear sprocket is too large in diamenter to pass through the opening at the front of the gearbox.
It appears that my only option is to remove the rear bearing from the shaft by sliding it rearward and then slide the first and second gears off the shaft toward the rear. The rear bearing is press fitted onto the output shaft and I'm not sure how to force the bearing rearwards while the gears are still inside the gearbox.
Anyone have experience with this?

My second question is that when the car was on the road it had a problem of slipping out of 4th gear and into neutral when under load or acceleration. The driver needed to hold the shift lever in 4th to prevent this. I thought I'd easily find something broken once I had the gearbox apart. So far, I've found no broken springs, clips or rings.
Does anyone want to venture a guess as to the cause of this one?

Thanks in advance for any help or ideas to try

 

[Wombat]

When I pulled my all synchro S IV transmission apart, I removed the nut holding the shaft to the rear bearing and removed the shaft through the front openning. I had to slide the 1st gear wheel off the shaft as I moved the shaft forward. The shaft (less 1st gear wheel) came out through the front openning and the 1st gear wheel came out through the top of the gearbox case. Non synchro first may be different.

As for jumping out of gear, check that there is no axial play in either of the bearings. Check the condition of the detent groves in the shift rail - the manual does give details of a test to measure the load required to move the selector fork. Check for wear on the shift fork. Check for wear in the teeth on the gear that the synchro hub engages on, also check for wear on the splines in the sliding sleeve of the synchro hub.