741 Transmission & Ring gear, what to check?

[Jim Liberty]

This is all way above my pay grade. If you are looking for a good trans. builder in So. Cal., I use DER TRANS. Jim Kaforski - 714-777-3806. Fast and priced right. 30 years in the business.
..............................Jim.

[Juha Vane]

Hi Jim,

I really would like to have someone to go thru my transmission,
but Jim’s shop is 5500 miles away. A bit too far. When I looked for
his location found this;

Sad to say, but just today I heard from my buddy Jon Chabot of
Topline Racing that our long time friend and ally, Jim Kaforski of
Der Transaxle, had a bout with nature and its wrath.

Hopefully Jim is OK.

A bit unfortunate for us on this side of the pond that 356 market
is so heavely located in the US.

[mats carlsson]

Hi Juha

I have some shims. Please let me know what you need. Maybee i can help.

Mats in Sweden

Hi Jacques,

The other bearing remain in the carrier but the other shim is 3,90mm.
It's not worn, no ridge on either side.
I contacted Peter Iversen earlier, but he must be busy with the 4-cam
stuff as I never heard of him.

I must find some correct thickness paper and make the 0,17mm gaskets.
Don't know where I could find the 0,10mm thicker shims locally.
Am I totall lost if I make the correct thickness gaskets, assemble just the
carrier with side covers and feel how much preload there is in the carrier
bearings? This transmission worked fine, not noisy, just the gearing was
not suitable for street use. After the preload is where it was, I can check
the ring & pinion with dye to verify correct pinion depth.
If then it's correct, I assemble the transmission. If not I have to seek
professional help.

[Juha Vane]

Hi Mats,

Thank's for your offer. I found 0,15mm and 0,20mm gasket material so I'm
not sure if I need new shims. Probably if use 0,20mm gasket the preload will
be same as it was before I took the gearbox apart.

Do you rebuild 741 gearboxes?
Do you have the tools to measure ring & pinion?

[mats carlsson]

Hi Mats,

Thank's for your offer. I found 0,15mm and 0,20mm gasket material so I'm
not sure if I need new shims. Probably if use 0,20mm gasket the preload will
be same as it was before I took the gearbox apart.

Do you rebuild 741 gearboxes?
Do you have the tools to measure ring & pinion?

hi Juha,

Sorry i dont do 741 only 519.
I have the VW tools to measure ring & pinion and backlash.

I can give You a name in Sweden who makes 741 gearboxes.
Maybee You can try Urbans Garage in Estonia?

[Juha Vane]

Thanks Mats,

I’ll ask Urban if I can’t do it by myself.

[Jacques Lefriant]

Hi Juha
Mats' tools should work in a 741. i use the same in both.
j

[Juha Vane]

Got the gears changed and now checking the ring & pinion contact with blue marking compound.
Measured the gaskets when I took it apart and they were in differential bearing cover 0,17mm
and the gear plate 0,23mm. As I changed the 3rd and 4th gear it is possible that the pinion depth
is not what it was before this operation.

Made 0,15mm diff cover gaskets and now have a 0,15mm on the ring gear side and no gasket
on other side to create some preload. There was no preload with 0,15mm on both side.

Have tried all kind of gasket combinations to get correct? contact pattern but see very little
difference in the contact pattern whatever gasket combination I use. Now I have 0,15mm
gear plate gasket and 0,15mm gasket on ring gear side. There is backlash in the gears.

Drive side is on the toe end of gear, about in the middle of gear but start from the very end of gear.
Coast side is almost complete gear, enclosed is couple of photos.
Wondering what I'm now doing wrong. This little car is surely making me humble...

Would be grateful for some opinions.

[Jacques Lefriant]

Hi Joha
http://www.adkusters.dsmynas.com/Websit ... _gears.pdf
what is your backlash?

[Juha Vane]

Hi Jacques,

The backlash is about 0,10 -0,15mm. I have no tool to measure it, but
locking the pinion I estimate it to be like that.

What concern me is that the drive contact start at the end of the tooth.
It's height vise in the middle of the tooth. I have so little experience with the
ring & pinion set up so I can't really figure out why the coast side contact is
so wide.

I locket the other wheel axle and braked with piece of hose and pliers the other
shaft to get little load on the gears.

[Jacques Lefriant]

Hi Juha
measure the backlash on the edge of the big reverse gear and divide by 3

[Juha Vane]

Hi Jacques,

Clever way to check the backlash, quite elementary but I didn't think that it can be done
like this also. Thanks!

With the 0,15mm gasket backlash was just a bit over 0,10mm, I changed the gasket to
0,20mm and now it's 0,16mm. I have a dial indicator, but left the magnetic stand for it
home, so these measurements are not as accurate as I would like them to be. But I got
repeatedly these numbers.

The contact patterns did not change much, now a bit shorter on both sides.
Apologize for the photo quality, the drive side contact is in the middle of tooth, but on
toe side, coast is also in the middle of the tooth, but spreading wider.

[Dave Erickson]

Juha, when I rebuilt my transmission I had two sets of gaskets and they varied considerably in thickness so that was a help. The set that was most useful was the one I bought from Jacques; it had some thinner and thicker gaskets that worked perfectly.

Dave

[Juha Vane]

After several gasket thickness variations, I believe I got it "right". Bought gasket paper and
made additional gaskets to have different thickness. Backlash is 0,13mm and there is some
preload (measured from diff side plate gap to transmission case). Now the contact pattern is
in the center of the drive side teeth and it's covering almost the whole teeth. This exercise
was quite time consuming. The photos I took didn't come us as good as the previous.
I'll see how this work out when I drive her. I have the other transmission if I screwed this up.