unidrive mount holes

[mrc 810]

hi men,  yesterday i finally attempted to install my spare unidrive tranny to my newly reinforced frame.  (see the thread 416-8 help needed)  the old tranny had 4 threaded BLIND holes.  the spare tranny has 2 threaded blind holes and 2 threaded thru holes.   i would think gear oil will leak past the threads on the 2 thru holes.   is this common?  what to use? silicone/rtv?  thank you.  mike in mass. 

[rmaynard 15,409]

Only the top holes are through holes. Never used any sealant on any of mine and they don't leak. Tranny fluid doesn't get that high unless you roll it over.

[stevasaurus 22,684]

I agree with Bob.  If you think you need to add something...put a finger of bearing grease in the hole with the bolt. 

Edited March 4, 2014 by stevasaurus

[SousaKerry 501]

If you want you can smear some silicone ore even pipe dope on the threads but it is not necessary.

[mrc 810]

hi guys, thanks for responding.  i can see where top thru holes might not be a problem.  however, in the spare tranny i wish to use, on a diagonal basis i have one bottom thru hole and one top thru hole.  put a dab of silicone or pipe dope and go for it???  thanks   mike in mass.

[stevasaurus 22,684]

The bottom one could be of concern.  I think I would mount the trans first...pull back out the bottom thru bolt...put some pipe dope on it and see what happens.    The trans really should bolt up tight to the mounting plate.  Like Bob said, I have never seen any leakage.  Just be careful to not use too long of a bolt, if you have through holes.  You could reach some moving parts. 

[rmaynard 15,409]

Don't recall ever seeing bottom holes drilled through.

[stevasaurus 22,684]

Hey Bob...I did not think there any through holes in the Wheel Horse trans mounts...but I'm with you...can't believe there would be one on the bottom.  My experience is in rebuilding them...I do not get to mount them back on the horses.  I just do not really know what to think here. 

[pfrederi 17,635]

Permatex High temp tread sealant.  I have used it many times even holds back gasoline.  also you only need a tiny amount so it is unlikely to get into places it shouldn't be...unlike RTV stuff

[rmaynard 15,409]

Hey Bob...I did not think there any through holes in the Wheel Horse trans mounts...but I'm with you...can't believe there would be one on the bottom.  My experience is in rebuilding them...I do not get to mount them back on the horses.  I just do not really know what to think here. 

I don't think Wheel Horse engineers would have designed something that would be an inherent leakage point without a sealant of some type indicated in the manual..

[Callen 64]

You could use a little blue loctite on the threads and let it set a few hours before you add fluids.

[mrc 810]

thank you men for responding,  i think i shot myself in the foot so to speak. prior to the attempt to install the tranny, i looked into the mount holes with a very strong flashlight. only one top hole was "open".  we had problems getting the bolts started.  we put the tranny back on the garage floor and i ran a tap thru the holes.  i now believe i must have broken thru one of the bottom holes.  now my concern is there may be metal fragments in the spare tranny.  one step forward and 3 back on this project. the wall must be thin as i had no problems with the tap.   thanks again.   mike in mass.

[Martin 2,131]

Hey Bob...I did not think there any through holes in the Wheel Horse trans mounts...but I'm with you...can't believe there would be one on the bottom.  My experience is in rebuilding them...I do not get to mount them back on the horses.  I just do not really know what to think here. 

 

from my experience, (which is limited compared to some of you on here) the only open holes I've found have been upper, and then its only been one and that was on the hi/lo boxes. the hole thats closest to the hi/lo selector fork inside the trans was open and that was because the case material is thinner there than at the other 3 holes. 

 

@ mike- chasing threads is always good but you have to watch how deep you go. what sort of tap are you using? a bottoming tap (one with an almost flat bolt like end) instead of your regular run of the mill taper (pointed end) works best for chasing threads. you really need to be careful on some threads, especially aluminum blocks like the onan engines etc. that you don't break through or push cut material into areas you don't want them. or worse still bottom it out and break the tap or pull threads.....

[mrc 810]

hi martin,  i did know there is a  difference from a starter tap vs. a bottoming tap.  iwas using a starter tap. being a 3/8X16 thread the starter tap has a slight taper but not a real point so to speak.  you are correct that the top hole is on the side of the hi/lo range selector lever.  i really did not feel much resistance when chasing the threads.  i assumed (incorrectly) that a cast iron unidrive tranny was stout enough to tap with no worries.  guess not.  live and learn.    mike in mass.

[stevasaurus 22,684]

Mike...I think I would open the trans and make sure no loose metal is in there.  (you probably know that)    A neat trick when mounting the trans back on the horse is, cut the hex heads off of 2 bolts 1 1/2" long.  File the burrs from cutting the heads off.  Start the bolts, by hand, in opposite corners of the trans...use them like studs.  Position the trans and start the other 2 bolts and tighten...then turn out your studs and add the other bolts.  This works great. 

[mrc 810]

hi steve,  with my work schedule these repairs that turn into projects really kill me.  at this point i've contacted mike (racinfool40) for gear parts for the original 416 tranny.  because of this tapping hole issue i now think i should split the spare tranny and go thru both.  what a major PITA!!!  to add to this frustrating situation the 416 is apart in the middle of the garage and i need to get it done so i can work on my truck.  when it rains it pours.  mike in mass.

[pfrederi 17,635]

A set of thread chasers is one of the most used tools in my shop.  Best 50 bucks i ever spent.  Does SAE NC and NF and Metric

 

http://www.sears.com/craftsman-48-pc-sae-metric-thread-restorer-kit/p-00942275000P?prdNo=1&blockNo=1&blockType=G1

[mrc 810]

hi paul,  i  have that exact set of thread chasers that are in your link. generally, enough to clean up most threads.  i ran the thread chaser thru the holes prior to the first attempt at installing the tranny.  when i had difficulty starting the bolts i then figured the thread chaser wasn't enough and i would have to tap the holes.   i think the real problem was the tranny even with a friend is awkward to handle.  steve's suggestion above about cutting bolts to use as guide studs would have probably helped me avoid this mess. mike in mass .

[stevasaurus 22,684]

Here is a shot of the stud bolts I made...this does make mounting the trans much easier....

 

[pfrederi 17,635]

On additional hint for the aligning pins...cut a slot across the unthreaded end.  Lets you use a flat tip screw driver to get it out if it gets a bit bound up...ask me how I know this

[Martin 2,131]

steves suggestion is the easiest way. i won't even attempt one with out the cut off bolts. just makes it so much easier and lessens the chance of cross threading or damaging the threads while the trans is being held still with all the holes lined up. very easy to screw up a thread if the trans or frame slips while you are doing it yourself.

this idea can be used to start head bolts while holding the gaskets in place and so many other scenarios as well......

 

i raise my glass of rock and rye to you steve........

 

wait, i don't have any.....

Edited March 7, 2014 by Martin