I hope this is refreshing to everyone as I don't think I have seen much of any discussion about our Jaguars in the last 50 emails I have from these forums over the last several days. I have a 1964 3.8 FHC E-type. I bought this car in pieces in 1987 and without boring you with the details (and horror stories) after 21 years I drove it for the first time late last year (2008). It is now a beautiful nut and bolt restoration with numerous upgrades for reliability and performance. A previous owner replaced the transmission with a full syncro 4 speed, (GB5019JS) that I assume came from a later 4.2 E-type. I paid a service garage long since out of business to completely rebuild the trans with all new bearings and syncros. I am not so sure this was actually completed which leads to my first question. Under acceleration everything seems great. When under deceleration when in third gear when the car slows to the point the engine is no longer or only slightly still slowing the car it pops out of gear. This similar situation has also happened in first gear but rarely as I am rarely in 1st decelerating. I have been told this problem is due to the syncro(s) being worn. Could it be something else like a worn or bent shift fork? If so is it possible to remove the top cover and fix or adjust the fork without removing the engine/tranny as a unit from the car? What is the best oil to use in the tranny? Would a heavier oil grade or a high performance Synthetic oil perhaps help?
I am willing to call anyone to discuss if you email a number to donetypeatyahoo.com. Let me know your timezone as I am on the west coast.
I have a few other questions but I am out of space so I will start another Post. Thank you in advance for your help and support. Regards Don

Submitted by bonnettoboot@e… on Thu, 06/18/2009 - 00:26

Hello Don, a timely intrusion. The probem has nothing to do with the synchros, they only slow down the spinning parts to make selection easier. My guess would be too much play in the output shaft. It could be a selector problem but I doubt it. In any case the cover can be accessed through the tunnel, it wouldn't hurt to take it off, that way you would be able to see where the lost motion is!