Rebuilding the tranny....

[Bob Carriere]

Took apart my first C15a tranny....appears quite simple....once I figured out how to remove the bottom shaft.

Considering that the tranny had about 2 litres of water under all the oil..... solution in which I bathed profusely when I removed the engine from the bellhousing last Fall..... I was surprised to see the condition of all the gears..... no chips.. no teeth missing.. and the lower bearing seem to be reasonably good....

Now for the question..... how do you test these roller bearing on the lower shaft or the upper ball bearings...???

Is it easy to get new ones by taking them to GBS and try to match new models.....???? what have you guys been doing.....

This is my learning tranny..... I have two good ones and two to practice on.... the practice trannys all have the same problems the two upper bolt tabs... I call them ears... through which the bolts go through to the bell housing are broken on one side....seems to be a weakness of this design. I expected to see more massive gear clusters....no synchros....straight cut gears... pretty small transmission when you consider the use intended for these trucks.

I would appreciate any tips... secrets.... on rebuilding... checking out for wear..... etc....

Appreciate your help.....

Finally Spring has arrived...!!!

[Hanno Spoelstra]

Originally posted by Bob C.
Now for the question..... how do you test these roller bearing on the lower shaft or the upper ball bearings...???

Bob, first do a visual check ....


Source: New Britain, Connecticut. An inspector at the Fafnir Bearing Company inspecting large roller bearing which will probably end up in an Army tank.

[Nick Bullock]

Hi Bob

I rebuilt a gearbox for my HUP last summer.. All the bearings are available off the shelf. Seals too... we had no trouble sourcing the bits... just took them all to the local factors... cost about 80 £ for all the bearings and seals.... worth doing.....

best wishes

Nick

[Bob Carriere]

Hanno

...I had not realized that you were so small..... and to think I said the tranny was VERY small for the truck size....

...if I ever need my watch repaired I will send it to you hahaha..

Nick

Thanks for the good news..... I am hoping that I will find a patient and preferrably older parts man at the local General Bearing Services who will be able to source the bearings..... I do not remember seeing any seals... would it be on the tail shaft where the u-joint flange fits???? it might still be inside the back cover which I have not washed yet.....

I am hoping to do the same on the transfer case.

Those anyone have North American parts number to share???

I will make a point of posting whatever after market parts I use.

[Alex Blair (RIP)]

Bob ..
A while back Harry Moon rebuilt some transmissions and we had a great debate and info session on MLU and the thread should still be around..Maybe Hanno can find it..There were pictures and parts and do's and don'ts ..and why the lugs were breaking on the casings..a missing or wrong part or spacer installed if I remember correctly...Maybe Harry can jump in and help..He is the residential C15 A Transmission speciallist..

[Hanno Spoelstra]

Originally posted by Alex Blair
A while back Harry Moon rebuilt some transmissions and we had a great debate and info session on MLU and the thread should still be around..Maybe Hanno can find it..

I did a search for all postings by Harry Moon, but did not find anything on this subject.
Was this thread you refer to on the Old MLU Forum, Alex?
Over to you, Harry!

[Alex Blair (RIP)]

Hanno..
It may have been on the old forum ,as you say ,but we had quite a good discussion with the pictures on the broken lugs and all...
The spacer is the critical piece and the bolt length ..if my memory serves me correctly..
Can we still get back to the old MLU stuff..??

[Pete Ashby]

Bob

If you take your bearings out you will find part numbers on the race and cage, these are either directly crossed referenced and or current as Nick has indicated, from memory you will not have trouble with unmatched cups and bearings,... in the Chev box they are all matched pairs. If all else fails get a set of callipers and measure the outside diameter of the cup and the inside diameter of the bearing (shaft diameter) and quote them to your bearing factors, same with the seal i.e. housing and shaft diameters, as Nick says should all be off the shelf.

As for determining ware, it's best to replace with new and save effort in a couple of years time. If however you want to try to save the originals try this:

Take the cage bearings and cups and wash out in petrol NOT paraffin, examine the cup for scoring and or pitting use an eye glass if you have one. If you find any it's scrap and so is the bearing. If the cup is OK next is the cage, spin the cage look for the pits or cracks spin it by hand and listen, ............if it crackles it's scrap and so is the cup.
The roller cage on the main shaft/primary cluster is next, you need to check the condition of the end cages if they are loose discard them if the rollers are marked or discoloured again discard them. Now check the condition of the internal bore of the primary shaft cluster it should be smooth and perfectly round (by measurement with callipers), if not junk the cluster and the rollers same for the bearing spigot on the main shaft.

Sounds a lot of effort, but done once and done right it will last forever, not done and the box will rumble and howl until it eventually digests it's self at a most inopportune moment.

Pete

[Bob Carriere]

I shall wash the bearing and seals carefully and jot down the parts numbers for a visit to the bearing dealer...... as suggested I prefer to do it the best possible way once...... and not have to worry about it again.

The few extra dollars now will save a lot of time and money if something breaks later... besides it is so easy to work by the work bench on a comfortable stool... as opposed to a wet road side at 9 in the evening with a torch stuck in your mouth trying to see what went wrong.

I sure hope you guys can recover all that precious info and pictures from the old forum....sounds like some of the information should be archived on the new site.......

As I have two trannys with broken tabs... one good one from my own truck... another maybe in a parts truck .... I want to make sure I have this spacer or bolt thing mentioned by Alex right before I break another one.

I never could explain why.... when I purchased the truck it had a complete but empty tranny shell in the back cargo box.... it is rusted but not broken..!!!

Now can someone wake up Harry Moon in BC.....

[Hanno Spoelstra]

Originally posted by Bob C.
I sure hope you guys can recover all that precious info and pictures from the old forum....sounds like some of the information should be archived on the new site.......

Bob, all threads were saved and can be viewed at the MLU Forum Archives.

H.

[Bob Carriere]

Thanks Hanno

I guess I will be going to be late tonite...... wonder if I can download on CD....

Will let you know which page when I find it....

CCCCHHHAARRRGGGEEEEEEEEE!!!