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MG TD TF 1500 - Should I replace 1st gear?

> Do I need to replace this 1st gear on the mainshaft of my TF gearbox? In the photos below, a couple of teeth on 1st gear on the mainshaft are chipped. Can they be dressed? The face of the teeth may be starting to deteriorate also (?)

The mating teeth on 1st gear on the laygear are failing worse. VIDEO:
http://youtu.be/0-JGPNywgZY

===========

My noisy gearbox is apart. Took some time off and now starting to look at it again. 2nd, 3rd, and 4th gears on the mainshaft and the laygear look good. However, 1st gear has problems on both. Not sure that they were responsible for my noisy gearbox, but they may be starting to break up.

I will replace the layshaft, which is starting to flake off at the needle rollers under first gear. I will replace all needle rollers in the gearbox and I will replace the bearings. Looks like I need to replace the laygear, too.

Here is a video of my noisy gearbox that I posted in another thread. It is noisy in all gears, not just first.
http://www.youtube.com/watch?v=gG31cnL7VnU
(search archives for 2015042615515914584)

I will have more questions as I proceed.

Thanks for your help,

Lonnie
TF7211

Image:

TOP - chipped tooth - sixth from left
MIDDLE - another chipped and worn tooth 4 & 5 from left
BOTTOM - complete first gear and 1st / 2nd sliding hub

LM Cook

Laygear is toast, and the main gear you can see damage on the mesh thrust surface.

I am sure you could find some good used parts somewhere.
mog

Lonnie,

The first gear teeth don't look to great, but also better than many I've seen which still have a lot of life in them yet.

I doubt you will get a quiet first gear even with new gears, as the straight cut gears are inherently noisy.

The noise in the other gears could well be the layshaft and bearings. Inspect and replace, if necessary, the lay gear thrust washers, and without a doubt the layshaft bearings, and layshaft if there is any indication of wear or spalling.
readlist

Cluster is toast, first borderline. I still suspect a bad clutch part may be causing the other gear noise, as well as the judder/rattle when starting out. Also check all of the remote housing springs and dampers. George
George Butz

>> Are any guidelines available regarding acceptable clearances between major components in a T-series gearbox?

As mog noted, my 1st gear has grooves under the selector fork. The fork has matching grooves. I looked at a new 1st gear a couple of days ago. It is smooth under the fork. The gap of the channel for the fork is worn wider in my gear than the new one. And the fork is worn thin. Same for 3rd gear. Seems to be a lot of slop between the gears and the forks. The forks are snug on the selector shafts.

I'll replace all needle rollers, bearings, and thrust washers. Possibly the front and rear plates for the thrust washers on the layshaft (?)

George - I am getting another pressure plate. Moss may give refund for the first one. I took all of the parts of my gearbox to Will Bowden (my idol) on Thursday. It was another great day of learning at MG University! He pointed out more parts that need replacing in the gearbox and discussed options.

This is not gonna be a cheap fix.

Lonnie
TF7211
LM Cook

Lonnie, some time ago, using NOS forks, I measured the shifter fork thickness in the area where they contacted the striking dog. It was found to be 0.290" plus or minus about 0.003". It was the same for both forks. I will see if I can find a NOS striking dog and, if I do, I will get back to you about the slot width.
Cheers, Hugh
H.D. Pite

Lonnie, I measured the width of the circular slot on a new (NOS??) 1st gear to be 0.298". Possibly it is 0.300" and my measurements with vernier calipers could be out a bit.
Cheers, Hugh

H.D. Pite

This thread was discussed between 02/06/2015 and 08/06/2015

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