Helicoil or bigger bolt
 

ok i know this is a bit off topic....but i have a few stripped bolt holes on my transmission in my truck **its a 4x4** the ones tht r stripped are the ones tht hold the transfer case to the trans....here is my question...do i helicoil it or bigger bolts?? its all aluminum sadly....2 holes i can run all thread threw and the other two i cant...so im kinda stuck here...i have the tools to pull it apart and do this but idk which to go with...been told going bigger is a bad thing to do any ideas?? im leaking a gallon of tranny fluid every 3 days...and the trans is fully rebuilt...so a little help

Hey Brandon,

When going with the helicoil option you are actually going to have to go with a bigger hole anyway to allow for the room for the thread insert itself. So if you have enough real estate to work with, a bigger bolt is a good option. Just make sure that you drill and tap the holes straight and you will be okay. On the ones that are thru bolted, is it possible that you could use longer bolts and put lock nuts on the back?
FWIW..........I have been around machine repairs most of my life and I do not like helicoils. There are other options out there that are somewhat stronger.
Here are the ones that I prefer:
EZ Lok
http://www.ezlok.com/InsertsMetal/carbonSteel.html

What is your truck? If you going to pull it out I would replace the stripped case and be done with it. You say the trans it rebuilt? Does it have any warranty or did you do it yourself? With only 4 bolts holding it on you want it to be as strong as possible, its got quite a bit of stress on when four wheeling. You can go with a bigger bolt and if that doesn't work then do a helicoil if a new case is out of the question.

I'd go with a bigger bolt if there's room.

ive never heard of EZ Lok before...ill check into it

its an old chevy k5 blazer. i had the trans rebuilt by a local trans man and he only warranties the insides not outside. its hard to explain without showing a pic. i can slide the transfer case back and redo the holes. i wont want to keep trying things cuz too many tries and things go bad

A pic of the area would help.

like what was said already, if you have the room Id drill and tap it . and go back with a fine thread s/s bolt and use anti seize to keep the aluminum oxidation from locking to the threads.

ill try 4speed. im gonna just go ahead and pull the transfer case out and drill it and tap it. im not to keen on fine thread bolts

I hope that this will fix a problem that I have?

Got to do some digging & see?

NIK,

Will post with pics later if EZ- lok does it?:bigthink:

Posted video on their site is dead, found. It on you- tube, McMaster & Carr has them in stock.

I don't think I'd use fine thread in Aluminum.
They might be metric, but I've seen both on hydromatics, just depends.
---IIRR on some of the early 700R4's ( don't know what you are into) they had 2 seals face to face, one in the trans,one in the transfer, so the fluids did not mix.
(Same fluid just different levels)
Might look to see if that is the case and easy to change now.
If you do have the face to face seals, then it should not leak with loose mtg bolts
just a heads up.