things not to do when soldering diff pin

[pascal_ladale]

since i bought my car, it always had some strange clunk when acceleration or decelerating so 2 weeks ago when i was fixing something on my brakes i noticed that there was something loose it the differential as i could rotate one wheel by 1/8 turn.

so i took off the trans, opened it to discover some serious damages... the previous owner said that he had soldered the diff pin but he didnt mention that he actually replaced it with one that he had made!



this is a simple diagram showing how the pin was on how it whould be.



it's difficult to see but the pinion gear were moving freely on the diff pin. what a mess it was in that trans when i opened it... the oil was full of steel particle. the magnet used to catch debris in the oil was like 4 times its size! i cleaned everything, put an other differential that i had, soldered its pin and put all back together. since then i had no problem at all, it runs smoother than ever and shift alot more easily probably due to the clean oil.

[pascal_ladale]

When soldering a diff pin, never replace it with a normal one, it MUST be a hardened one or you'll end up with serious problem!

[Dr B]

I have seen several WELDED dif. pins ,here on the forum ......
It is my thought ....... MY thought only !
the more welding you do ,the more you weaken the assembly .
that being said .....I would only put about three spotwelds
on each end of the pin carrier,just enough to keep the pin from being able to slide out if the rollpin fails .

[pascal_ladale]

when you solder your diff pin you heat it, the fact is that when you let it cool it weaken the pin cause' it's the reverse procedure of hardening. to have best result i think its best to solder it by small step so it wont heat to much... just my opinion.

[pascal_ladale]

but that was really bad since he replaced the pin with a non-hardened one..

[Sky King]

I have to ask, you SOLDERED it as opposed to WELDING? The soldering process does use MUCH less heat but because it is usually 60% tin and 40% lead it is MUCH weaker. Silver solder is stronger but still considerably weaker that welding. A bit stronger but still weaker that welding is brazing but again weaker than welding. I just don't think I would trust my differential to anything less than welding.

[pascal_ladale]

sorry but i meant welding...

i only speak french, sorry for my poor english

[Dr B]

O K it is being welded ! GOOD .
I think most of the other people doing this ;
beveled the ends ,fluted the carrier ends ,so as to make an area for the weld
to set into ,as opposed to surface only welding .
They may have ground down the ends of the pin also.
it has been a year or so since anyone posted this procedure .
there should be some interesting write-ups in the how to section.

[shak911]

Originally Posted by pascal_ladale

since i bought my car, it always had some strange clunk when acceleration or decelerating so 2 weeks ago when i was fixing something on my brakes i noticed that there was something loose it the differential as i could rotate one wheel by 1/8 turn.

so i took off the trans, opened it to discover some serious damages... the previous owner said that he had soldered the diff pin but he didnt mention that he actually replaced it with one that he had made!



this is a simple diagram showing how the pin was on how it whould be.



it's difficult to see but the pinion gear were moving freely on the diff pin. what a mess it was in that trans when i opened it... the oil was full of steel particle. the magnet used to catch debris in the oil was like 4 times its size! i cleaned everything, put an other differential that i had, soldered its pin and put all back together. since then i had no problem at all, it runs smoother than ever and shift alot more easily probably due to the clean oil.

I am having a similar noise coming from the same area, first I thought the brake pads are the cause, but I can't reproduce the noise without being on the road, clunking like, at around 20 mph/ however with engine off and 1 wheel off the ground I do hear a clunk when I rotate the wheel, and the clunk is coming from the diff, I guess my question is what is too much of a play, in terms of degrees, any help is appreciated

[pascal_ladale]

difficult to say in term of degree... maybe 2-3. since i repaired it, there is almost no play at all. if i rotate one wheel i'll hear the gear in the differential, if you can rotate one wheel and you dont hear any sound off the diff there may be a problem.