knackered thread on transfer box.. what are my options?

[jimllshiftit]

After driving home last week with a lovely "crunchy bearing" noise coming from under my 1992 200tdi D90 and also getting home to find my handbrake was non existent, i decided to replace my transfer box.

Today ive got the replacement used transfer box in place with the mounts back in but ive found that the big bolt that goes right in the middle of the box just infront of the high/low range selector wont tighten up, probably because there is no thread left in the transfer box.

What are my options? What size is that bolt? if its M10 can i just tap a 7/16th thread into it and use a 7/16th bolt? If i just thread lock the original bolt in place will it sufficiently seal the mating faces from future water ingress?

I dont really want to drop the transfer box out again if i dont have to, but it may become the only option. What would your approach to solving this knackerd thread problem be?

 

[v8250]

Assuming the bolt is the correct size, the only proper way is to drill out and helicoil. Or, you may be able to tap out to 7/16th.

I wouldn't just thread lock.

 

[jimllshiftit]

Thanks. Ill drop the box out and do it properly.

 

[jimllshiftit]

Today ive removed the transfer box once again and tapped the butchered thread out to 7/16 UNF which seems to have worked nicely. Box is now back in again and bolted down solidly all round.

Sadly, ive now found that the "new" box has an electronic speedo drive whereas my old box is mechanical and has a slightly wider worm drive cable.

Ive read that they "just pop out".... why do I get the feeling that that is easier written than done? Are they really that easy to swap over?

 

[Hicap phill]

Today ive removed the transfer box once again and tapped the butchered thread out to 7/16 UNF which seems to have worked nicely. Box is now back in again and bolted down solidly all round.

Sadly, ive now found that the "new" box has an electronic speedo drive whereas my old box is mechanical and has a slightly wider worm drive cable.

Ive read that they "just pop out".... why do I get the feeling that that is easier written than done? Are they really that easy to swap over?

Long nose pliers into the speedo drive & pull.
This may loosen up the flange they holds it in place.
The flange is held in by rust/corrosion rubber O ring

 

[Hicap phill]

Also it may be easier if the handbrake drum is off

 

[jimllshiftit]

Thanks Chaps ... all sorted and back up and running now. The"old" speedo drive was well and truly corroded in, as you said, 'Phill, so i had to take the output shaft off and knock it out with a punch. Thankfully the speedo drive in the "new" box came out much more easily and the handbrake assembly was already off anyway.

All ticking along nicely now though which is encouraging. Not sure if this is the best box though as I found a sizeable lump of metal on the end of the drain plug when I came to change the oil..... it was probably about a 1mm or 2 square which was a bit worrying......

 

[v8250]

Thanks Chaps ... all sorted and back up and running now. The"old" speedo drive was well and truly corroded in, as you said, 'Phill, so i had to take the output shaft off and knock it out with a punch. Thankfully the speedo drive in the "new" box came out much more easily and the handbrake assembly was already off anyway.

All ticking along nicely now though which is encouraging. Not sure if this is the best box though as I found a sizeable lump of metal on the end of the drain plug when I came to change the oil..... it was probably about a 1mm or 2 square which was a bit worrying......

Don't worry about the piece of metal too much. The main thing is that it's out of the box so can't do any more damage. Just keep the box oil fresh and all should be fine.

 

[davidwatson]

After driving home last week with a lovely "crunchy bearing" noise coming from under my 1992 200tdi D90 and also getting home to find my handbrake was non existent, i decided to replace my transfer box.

Today ive got the replacement used transfer box in place with the mounts back in but ive found that the big bolt that goes right in the middle of the box just infront of the high/low range selector wont tighten up, probably because there is no thread left in the transfer box.

What are my options? What size is that bolt? if its M10 can i just tap a 7/16th thread into it and use a 7/16th bolt? If i just thread lock the original bolt in place will it sufficiently seal the mating faces from future water ingress?

I dont really want to drop the transfer box out again if i dont have to, but it may become the only option. What would your approach to solving this knackerd thread problem be?

Its worth having a go with J-B Weld 8265S as that was developed to fill scratches in cylinder bores so its going to hold your bolt in without a problem