Moss box whine in 1st, 2nd & 3rd gears

[Mr_C]

Hi Guys, need help.

1962 FHC, Moss EB JS Gearbox whines in all gears except 4th.Stripped it down expecting to find burrs on the gears , shafts scored or bearings seized or worn out. However I can't see anything wrong. It all looks perfect , even down to the needle rollers on the lay shaft. I expected the whine in first gear due to the straight cut gears. Could it be that a previous owner fitted non JS gears that don't mate properly hence the whine on 2nd and 3rd and how can you tell if that is the case ?

Any help or advice would be much appreciated.

[TonyB]

The only gears under load in those three gears is the drive from the input shaft to the layshaft, so I would look at them first. Also that is the only time the input shaft bearing is loaded so clean it with solvent and see if it spins freely, though I would replace that whenever the box is in bits. Ditto for the output shaft bearing. The most common fault is wear on the layshaft under the needle rollers at the 1st gear end, so look at that closely and put a micrometer on it. However, wear there quickly gets worse and is usually quite visible. The same goes for the needle roller bearing between the shafts. If the gears are unmatched the form may look different, but as far as I know the originals were all the same. If they are wrong this may show up as different backlash to the other gear pairs. Backlash is measured with a dial gauge on a tooth at right angles to the radius to the centreline. Check all round the rotation because a variation in backlash between teeth makes a lot of noise, something that can only be a manufacturing fault. A chipped tooth could also make a whine. It would also be worth checking you do not have a bent selector fork. Good luck.

[Mr_C]

Thank you for your reply Tony. I have had the gearbox to bits , checked the shafts for scoring , checked them with a micrometer, gave them a very fine polish in the lathe with 400 grit emery cloth. The gears themselves were very shiny and there was no backlash between them. The two shafts that the gears run on appear to have been machined in the gearbox housing too close together thus not enough clearance between the gears and causing the whine. I replaced all the bearings as a matter of course including the needle roller bearings . Reassembled it ,filled it with SAE 30 oil , ran it and it still whines . It’s probably whined when it was new. It will probably whine for another 60k + miles. It’s certainly a very robust gearbox. At least I know it’s not about to fall in bits anytime soon. The only way I can see to cure the whine would be to blank off one of the shafts and re machine new holes with a greater distance between the shafts to allow for a small amount of backlash between the gears . Perhaps there may be a simpler way?

[TonyB]

I missed out to check for wear in the bore of the lay cluster where the needle rollers run. I check that bay assembling the laygear on the shaft and put the end of the shaft in a vice with soft jaws and check for play with a dial gauge. There should be no movement.
I have never met a wrongly machined gearbox casing in a complete career in engineering and a lifetime hobby of working on racecars and road cars. Of course it is possible and the easiest solution would be to change the casing. In case you are worried about matching numbers, I have seen one of the faces presumably used to mount the case for machining with the one also used for stamping the numbers machined lower than the other.

[Mr_C]

There was maybe a couple of thousands of an inch play but I assumed that was acceptable. Perhaps that’s why it still whines. I didn’t check it with a dti but I still didn’t have any backlash/ clearance between the gears. I also found it hard to believe that the holes were bored too close together and why I thought maybe some one had mixed the Jaguar shaved gears with the unshaved ones. Many thanks again Tony for trying to solve this noisy gearbox. You may have hit the nail on the head about the bores the needle rollers run in.

[TonyB]

Perhaps the gears are aftermarket. On jag-lovers Redline oil was recommended for the gearbox and subjectively I think it made my EJ (early 4.2) box a bit more quiet. Your 1st gear is straight cut and that will always whine.

[Mr_C]

I did have Redline MT 90 on order for a couple of months around Christmas but was out of stock and that’s why I ended up using SAE 30 . Perhaps I’ll try again, might be back in stock. Some of the gears had Jaguar part numbers but not all so it’s anyone’s guess what gears have been replaced over the 63 years. If all else fails I’ll just have to purchase two pairs of ear defenders for me and my wife.
Thanks again Tony,

Kind regards,
Paul