Stripped transfer case plug won’t go back in

Status
Not open for further replies.
Joined
Jan 11, 2007
Messages
953
Location
El Oeste
Servicing the transfer case on my Suburban. Both the fill and drain plug came off easy enough but the drain plug is stripped and won't thread back in. (It will just a few threads to the point it will hold fluid, but I wouldn't trust it for too long.) I ordered a new plug and it won't go on at all. The result is a truck I can't drive and one of those knots in my stomach like oh s—t!.

Any suggestions on the best course of action? I have a tap and die set but it's too small to use on this project. It would be great not to mess up the case. Thanks!
 
Originally Posted by oldhp
Get the right size tap and clean the threads. 3/8" pipe??? You should be good to go.


Best bet, right there. It's got to be either an aluminum or magnesium TC housing, so it should be easy to tap. Just step up to the next size and give 'er heck, that's after finding a matching plug of course. I'd bet it's an 18x1.5 thread pitch, so maybe step up to a 3/4 x 20 or something of the like?
 
You could take the plug to an auto parts store and see if they have a repair plug. They are usually just slightly larger with the same thread and a self tapping first couple threads that end up inside. I know they make them in oil drain sizes and would guess the transfer case would use similar.
 
Originally Posted by HawkeyeScott
2008 Suburban 1500. This is the bolt I'm working with:

Yep, I have the same one and it is sketchy at best. I'd take it down to a 4 x 4 shop and show it to them. They might be able to tell you what die it needs.
 
Last edited:
Depending on the size, they sell these at Walmart...for a TEMPORARY fix until you get yours sorted out.
[Linked Image from dougrussell.com]
 
See whatsic=ze the plug is and see if there is a pipe plug or a self tapping drain plug that will work. I had the drain plug strip when removing theoilpan drain plug on my tractor so I tapped the hole for a pipe plug and it works fine. Aluminum easy on assembly and at times disassembly.
 
Originally Posted by samven
You could take the plug to an auto parts store and see if they have a repair plug. They are usually just slightly larger with the same thread and a self tapping first couple threads that end up inside. I know they make them in oil drain sizes and would guess the transfer case would use similar.


Yeah, this! Did it on a neon. The +1 size went in scratchy and tight, and I had high confidence in it.
 
See if the threads are the same as an O2 sensor (use a thread gauge or put the threads from a O2 and the new plug together, don't guess). If so you can use a 18mm spark plug/O2 sensor thread chaser available at any auto parts store.

https://www.amazon.com/Lisle-20200-...d=1584013502&s=automotive&sr=1-4

Edit: Regardless of which tool you use either a chaser or tap make sure to grease it up good, clean off and regrease if making more than one pass.
 
Last edited:
I think I'll try and clean up the threads that are there -- it looks like just the first couple on the transfer care are compromised. The goal being to use the OEM bolt/magnet instead of going to something bigger.

Any advice on how to figure out exactly what size tap I'll need?

Thanks a lot. I appreciate it.
 
Originally Posted by Kira
If it caught at all I'd consider using Permatex Ultra Black on it.


That is what I was thinking of , as a Red Neck " fix " .
 
Originally Posted by HawkeyeScott
I think I'll try and clean up the threads that are there -- it looks like just the first couple on the transfer care are compromised. The goal being to use the OEM bolt/magnet instead of going to something bigger.

Any advice on how to figure out exactly what size tap I'll need?

Thanks a lot. I appreciate it.


A caliper and thread pitch gauge or bolt size gauge like the ones you see in the hardware store only bigger. I have a plug for a GM here. its M18 x 1.5, I cant say yours is this one or not but if it is a 18mm spark plug chaser like the one I linked to will do the trick with no problem.
 
Took the plug to my local Ace store and was able to figure out it is a 14mm with 2 pitch. No local taps in that size so I ordered from Amazon. Plan to finish the project once it arrives.
 
Status
Not open for further replies.
Back
Top