look at this trans mount plate lol

[Elkskin's mower junkyard 1,117]

so when i got the 701 guy told me frame is busted. so tonight i talked to my cousins fiance. asked him if he could weld it up for me. so i took it over there pulled the trans out and found a badly broken trans mount plate. so he told me that best thing to do is weld it up and then put the brace plates back on that one of the previous owners made. and thats what we did. we used some wood vises to pull the plate back together.

[953 nut 51,680]

Poor little  seems to have been abused, glad you are showing it some love.    

[HeyMrP 83]

That's what's called "adding character!" Nice job.

[Tankman 3,515]

Somewhere in the forums, details on the repair you just finished.

 

The '90 520-8 I purchased sometime ago, trans to frame was repaired beautifully. Textbook project. 

 

The problem you had seems somewhat common.

[Elkskin's mower junkyard 1,117]

1 hour ago, Tankman said:

Somewhere in the forums, details on the repair you just finished.

 

The '90 520-8 I purchased sometime ago, trans to frame was repaired beautifully. Textbook project. 

 

The problem you had seems somewhat common.

we have had others welded up. but this is worst one we have seen in person. dads 502 was cracked, 753 and 754 was cracked. 

[daveoman1966 3,611]

IMHO... you should reinforce the corners or they will just crack again.  I use 1/4" 2x2 angle iron, drilled and mounted with 3/8 bolts and nylok nuts.  If you opt this method, do one side at a time.

[Elkskin's mower junkyard 1,117]

2 minutes ago, daveoman1966 said:

IMHO... you should reinforce the corners or they will just crack again.  I use 1/4" 2x2 angle iron, drilled and mounted with 3/8 bolts and nylok nuts.  If you opt this method, do one side at a time.

way ahead of u. previous owner had those made up lol

[Tankman 3,515]

6 hours ago, daveoman1966 said:

IMHO... you should reinforce the corners or they will just crack again.  I use 1/4" 2x2 angle iron, drilled and mounted with 3/8 bolts and nylok nuts.  If you opt this method, do one side at a time.

I used bolts into the trans, bolts 1/4" longer than stock.

 

Along with Threadlocker Blue and locknuts.

[Sarge 3,462]

Once cracked and welded - those plates become quite brittle and usually shatter if loaded really hard , especially using a blade with heavily weighted tires and/or chains . I re-welded my 1277 twice , both times the cracks were fully v-ground and gap welded all the way through with 7018 rod . It is completely shattered now and will be replaced with either 3/8" or 1/2" steel plate . I'll try to get time when I do the job to detail it in a thread of it's own for future reference and will notch the plate to keep the engine to trans distance as stock . I think there is room enough in there to use a thicker plate and avoid the cross shafts for the older hydro linkage and brake rods, ect...we'll find out in the spring . The weak point becomes the 4 tapped mounting holes in the trans case - there may be a way to add additional braces elsewhere to the main case - need to study that further .

 

The stock as-built design utilized a bar on the top that locked the hydro block to the trans tunnel . While I'm sure it helped , it also pushed forces against the trans tunnel's sheet metal to crack it in several places as well , resulting in a seriously weak frame that would flex terribly when lifting a snowblower - you could see the trans tunnel as well as the dash stand flexing out of shape . I want to figure out a better way to triangulate the whole thing and stop at least most of that flexing - over time it destroys everything and this thing is the go-to heavy worker . I was really tempted at one time to build a new frame from rectangular tubing with 3/16" wall , but finding the right size to make it all work was pretty much not going to happen and dealing with all the different mounting points and shafts would be a pain in the butt...

 

Sarge

[pfrederi 17,147]

I would rather have a broken frame plate than a broken transmission case.

[cleat 4,984]

If the frame cracks and a couple of bolts lose their hold then the remaining ones do all the work.

 

I would think at that point you might be at a higher risk of trans breakage.

 

 

[Lee1977 6,217]

My frame wasn't broke but I fixed it anyway.

 

picture share

[AMC RULES 36,945]

It's the  Achilles heel...

most probably caused by ramming snow into piles.

 

 

[Adam 6]

I have a small crack forming on mine should I bother welding it up or just bolt on reinforcements? 

[daveoman1966 3,611]

As someone noted earlier, welding makes the metal brittle and more subject to fatigue.  Reinforcement with angle iron and 3 or 4 bolts from each side corner as shown would be a better long-term remedy.  If the angle iron parts are made and fit correctly, they will 'draw in' the cracks as nuts are tightened.  You will need to have 4 bolts 1/4 inch longer than original when threading into the cast iron trans case, (to make up for the thickness of the angle iron parts).   

[JPWH 5,308]

When I rebuilt my 854 I welded a plate inside the frame. Now the mounting plate is about 1/4" thick.