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Mr Stubs · 04-13-2015, 11:14 AM

I'm figuring out tranny mounting options on my tube chassis crawler. The easiest mount option is a 10" bushing span. The sleeve would be a 5/8 ID, 1/8 wall, and 7/8 OD. I would use a 5/8 threaded rod and .120 wall 1 3/4 DOM on the outside.

Think this is to long of a span?

Mr Stubs · 04-13-2015, 11:21 AM

In this location.

Cooter! · 04-13-2015, 11:27 AM

I don't quite understand but that span looks fine to me.

I wouldn't use threaded rod though. If you can get a hardened bolt that's long enough, maybe 2 short bushings and 2 bolts instead of that one long one?

smewhtguy · 04-13-2015, 11:54 AM

I have done an 8" span for a tranny mount and it worked fine, that was 4 years ago and haven't heard of any problems from the guy.

spidr · 04-13-2015, 12:39 PM

I cut the flanges off bushings to span the gap between so there is no way for the bushings to pinch and pull into the tube, I also did one that I welded a washer onto the inner sleeve to serve the same purpose. Dosent make me comfortable thinking that it could pull in.

havasusprings · 04-13-2015, 04:46 PM

Why not use 2 sets of bushings? One at each end of your 10" tube, turned 90* from the way you have it planned. You would then have two shorter bolts and no questions on the bushing span.

JR · 04-13-2015, 05:06 PM

The span is isn't that crucial. Wider has better leverage but sometimes it's too much depending on the rest of the mounts. Motor and trans mounts need to breath together without one taking all the torque.

Whatever the span is, the bolt needs to be accessed. If it's a 10" span, the mounting bolt needs to be pulled through without hitting frame rails etc.

Sometimes it's better to work with what hardware is available. A 10" span means a 11-12 inch bolt. Get the bolt first and make everything around it.

I don't recommend using all-thread.

trialsintrigger · 04-13-2015, 06:19 PM

Could you make a new inner steel sleeve that's threaded on both sides and use 2 short bolts on either side? Just a thought.

TBItoy · 04-13-2015, 08:02 PM

You can get hardened all thread, as long as you use a inner sleeve as planned it'll be fine.

We use all thread all the time on production machines.

havasusprings · 04-13-2015, 08:38 PM

Jr brings up a good point. My trans mount bushings are the same width apart as my motor mounts. If possible, they should be the same or the narrower if the two will do most the work, and promote flex throughout the drivetrain. People get away with different size mounts all the time, but it doesn't make it right.

04-13-2015, 11:14 AM	#1 (permalink)
Mr Stubs Registered User Join Date: Nov 2007 Member # 102813 Location: PNW, land of liquid sunshine Posts: 8,918	Bushing span distance question I'm figuring out tranny mounting options on my tube chassis crawler. The easiest mount option is a 10" bushing span. The sleeve would be a 5/8 ID, 1/8 wall, and 7/8 OD. I would use a 5/8 threaded rod and .120 wall 1 3/4 DOM on the outside. Think this is to long of a span? Attached Images __________________ [COLOR="Magenta"]Help bring back Swartz Canyon, Join To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. [/COLOR] [COLOR="Lime"]The good guys...[/COLOR] [COLOR="Red"]Marlin Crawler, Hellfire Fabworks, Dave'z Offroad, gearinstalls.com (Zuk), Diamond Axle, RADesigns, Advanced Adapters, Jantz Engineering, G-Fab motorsports, Got Propane, JHF [/COLOR]

04-13-2015, 11:21 AM	#2 (permalink)
Mr Stubs Registered User Join Date: Nov 2007 Member # 102813 Location: PNW, land of liquid sunshine Posts: 8,918	In this location. Attached Images __________________ [COLOR="Magenta"]Help bring back Swartz Canyon, Join To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. [/COLOR] [COLOR="Lime"]The good guys...[/COLOR] [COLOR="Red"]Marlin Crawler, Hellfire Fabworks, Dave'z Offroad, gearinstalls.com (Zuk), Diamond Axle, RADesigns, Advanced Adapters, Jantz Engineering, G-Fab motorsports, Got Propane, JHF [/COLOR]

04-13-2015, 11:27 AM	#3 (permalink)
Cooter! Permanent Newb Join Date: Dec 2010 Member # 176672 Location: Crawling up your skirt. Posts: 2,976	I don't quite understand but that span looks fine to me. I wouldn't use threaded rod though. If you can get a hardened bolt that's long enough, maybe 2 short bushings and 2 bolts instead of that one long one? __________________ If the answer to your diagnostic test is indeterminate, you must enlarge the context of the question. Peterson's 4 Wheel & Off-road UA2014 Alumni.

04-13-2015, 11:54 AM	#4 (permalink)
smewhtguy Registered User Join Date: Oct 2007 Member # 100827 Location: murfreesboro Tn Posts: 9,900	I have done an 8" span for a tranny mount and it worked fine, that was 4 years ago and haven't heard of any problems from the guy. __________________ I do math and stuff, on a professional level.

04-13-2015, 12:39 PM	#5 (permalink)
spidr Registered User Join Date: Oct 2005 Member # 55444 Location: Vancouver Island Posts: 12,261	I cut the flanges off bushings to span the gap between so there is no way for the bushings to pinch and pull into the tube, I also did one that I welded a washer onto the inner sleeve to serve the same purpose. Dosent make me comfortable thinking that it could pull in. __________________ [CENTER]I have Dumb Ideas[/CENTER]

04-13-2015, 04:46 PM	#6 (permalink)
havasusprings Registered User Join Date: Sep 2008 Member # 120768 Location: Lake Havasu, AZ Posts: 411	Why not use 2 sets of bushings? One at each end of your 10" tube, turned 90* from the way you have it planned. You would then have two shorter bolts and no questions on the bushing span.

04-13-2015, 05:06 PM	#7 (permalink)
JR OG13 King Join Date: Dec 2001 Member # 8524 Location: Agua Dulce, CA. Posts: 7,875	The span is isn't that crucial. Wider has better leverage but sometimes it's too much depending on the rest of the mounts. Motor and trans mounts need to breath together without one taking all the torque. Whatever the span is, the bolt needs to be accessed. If it's a 10" span, the mounting bolt needs to be pulled through without hitting frame rails etc. Sometimes it's better to work with what hardware is available. A 10" span means a 11-12 inch bolt. Get the bolt first and make everything around it. I don't recommend using all-thread. __________________ To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

04-13-2015, 06:19 PM	#8 (permalink)
trialsintrigger Registered User Join Date: Dec 2004 Member # 40301 Location: Tacoma, WA Posts: 1,055	Could you make a new inner steel sleeve that's threaded on both sides and use 2 short bolts on either side? Just a thought. __________________ You can't believe everything you read on the internet. That is how WWI got started.

04-13-2015, 08:02 PM	#9 (permalink)
TBItoy Registered User Join Date: Feb 2005 Member # 43587 Location: Cookeville, TN Posts: 5,495	You can get hardened all thread, as long as you use a inner sleeve as planned it'll be fine. We use all thread all the time on production machines. __________________ The Gremlin - small ugly linked beater Toyota

04-13-2015, 08:38 PM	#10 (permalink)
havasusprings Registered User Join Date: Sep 2008 Member # 120768 Location: Lake Havasu, AZ Posts: 411	Jr brings up a good point. My trans mount bushings are the same width apart as my motor mounts. If possible, they should be the same or the narrower if the two will do most the work, and promote flex throughout the drivetrain. People get away with different size mounts all the time, but it doesn't make it right.

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