bushings for custom fab.

[drbobxj]

Hey,

Where do or what bushings do people use for make custom stuff, like skid plates

can't find any pics right now of what I'm talking about, but the ones that you could weld to a tube, look to be about 2.5" long??

 

[CRASH]

OEM YJ rubber bushings are 1.25" and 1.5". 72-91 Dodge front spring bushings are 1" All available at any NAPA.

 

[Jes]

... what bushings do people use for make custom stuff, like skid plates

This confuses me.

 

[drbobxj]

like the ones in this picture.

With the tube and rubber, or do they just use the rubbers from like that CRASH said (YJ) and get a tube to fit?

just to clear this up I going to make a TC mount/ flat skid and not use the stock TC bushing .

 

[CRASH]

just to clear this up I going to make a TC mount/ flat skid and not use the stock TC bushing .

This is a very bad idea for long term durability. With trans mounts at the frame rather than under the trans/tcase, the amount of deflection is insufficient to not stress your driveline components.

I have seen cracked bellhousings, trans cases, and engine blocks from having flexible motor mounts and inflexible mounts downstream.

The rule is to either solid-mount the whole driveline, or keep it all squishy.

 

[drbobxj]

Yeah, sorry should have said I will do something about the motor too..

But so is the YJ bushing with or without the tube?? and what size tube would work??

 

[CRASH]

Those are outside diameters I gave you, so the 1.5" slips right into a 1.75" x .125" wall DOM tube.

 

[drbobxj]

Those are outside diameters I gave you, so the 1.5" slips right into a 1.75" x .125" wall DOM tube.

thanks I will check them out

 

[ZPD]

wouldn't you want your skid plate to be rigid though? If the whole skid/crossmember has flexible mounts to the frame then every time you hit it you will move your engine and tranny around.

 

[BrettM]

offroad shops like PolyPerformance.com and Mad4wd.com sell poly bushing with the appropriate tube it fits inside.

 

[Roxtar]

Yahoo or google search for "poly bushings" will find tons.

 

[XJ_ranger]

This is a very bad idea for long term durability. With trans mounts at the frame rather than under the trans/tcase, the amount of deflection is insufficient to not stress your driveline components.

I have seen cracked bellhousings, trans cases, and engine blocks from having flexible motor mounts and inflexible mounts downstream.

The rule is to either solid-mount the whole driveline, or keep it all squishy.

so you suguest using poly Motor mounts or hard mounting the engine if you make a cross member like drbobxj is talking about?

I can live with poly bushings, but Hard mounting the engine would not be fun...

 

[CRASH]

so you suguest using poly Motor mounts or hard mounting the engine if you make a cross member like drbobxj is talking about?

I can live with poly bushings, but Hard mounting the engine would not be fun...

Well, if you limit deflection downstream of the motor, and leave the motor on the floppy OEM mounts, you are placing a bunch of additional torsional stress on the bellhousing. The rule is, if you hard mount the trans side, you need to hard mount the motor. Vice-versa would be OK, as you'll have controlled the torque at it's source.

Sending torque back and forth through components not designed to accept it is never good. I've seen Chevy bellhousings break when subjected to this, but I heve never seen a 4.0 bellhousing broken. So, it may live, but it's not recommended. Maybe you can design it so the uni-body takes up the torque?

Seriously, if you used big rubber bushings at the frame ends, they ought to allow some deflection, maybe even enough to get away with OEM mounts. But poly at the frame, with the trans mount acting on a 16" torque arm (32" frame/2), doesn't seem like it would have very much deflection, if any.

 

[BrettM]

I went through 2 stock rubber tranny mounts in 2 months with stock rubber motor mounts (okay, they were little shot, but still...). I then made some poly motor mounts and am still using a rubber tranny mount and so far everything is just dandy.

just throwin in my experience... it would seem to me that having equal rigidity or more rigidity at the motor are good ways to go, but definitley a bad idea to have more rigidity at the tranny.

if I ever re-do my tranny mount it will be like Jes', still the best/coolest/easiest method I've seen.

 

[CRASH]

if I ever re-do my tranny mount it will be like Jes', still the best/coolest/easiest method I've seen.

Until you see my new design. It's the trans mount that isn't.

 

[Timber]

I like his mount, too, but it'd be nice if I were able to see it in person. It does look pretty simple--almost to the point that I'm not even sure I get it (if that can possibly make sense).

 

[BrettM]

I like his mount, too, but it'd be nice if I were able to see it in person. It does look pretty simple--almost to the point that I'm not even sure I get it (if that can possibly make sense).

Jes'? cut/drill a piece of plate to bolt the the tranny. cut the bushing end off a shackle. weld remaining of shackle to previously mentioned plate. cut the end off a leaf spring. drill leaf spring and bolt to crossmember. attach shackle piece to leaf spring piece. done.

what's the problem?

 

[Jes]

Actually it was easier than that.
The plate bolted to the tranny was a piece I cut off the stock transmission mount, so all there was to do was weld the half of the shackle to it.

 

[XJ_ranger]

Actually it was easier than that.
The plate bolted to the tranny was a piece I cut off the stock transmission mount, so all there was to do was weld the half of the shackle to it.

you dont have any problems with the trans moving around? seems like it would want to rotate around that one point...

but that sure is a very simple solution to a custom tranny mount...

 

[Jes]

you dont have any problems with the trans moving around? seems like it would want to rotate around that one point...

but that sure is a very simple solution to a custom tranny mount...

It doesn't move around but how is it different than the stock one?
The stock one is still only rubber that is about 3.5"s wide.