TravcoForum.com

Travco Classic Motorhome Support & Discussion Forum

Skip to content

Change font size

Board index » Maintenance » Drivetrain
Transmissions, Rear Diff, etc.

swapping rear axle assembly

Unread postby rampeyboy on Mon May 18, 2015 6:14 pm

So, lots of talk about the lack of ratio options for the Dana70HD. Some interest in Cummins conversions. Anyone swap a complete rear axle, drum to drum for a better ratio? Maybe something out of a newer rollback, box truck or other motorhome, or even a school bus? How about tire wheel combo's. I know the 5 lug wheels are a limiting thing, but if there were a 22.5 or 20" wheel in that pattern, could we use a taller tire to bring the RPMs down on the highway? Would a 22.5 tire such as an 11R22.5 even fit in the wheelwell?
I was thinking of buying a school bus donor with 5.9 Cummins, AT 545, and also maybe the rear axle??

Boyce
rampeyboy
New Member
New Member
 
Posts: 9
Joined: Sun May 17, 2015 12:43 pm
Travco Model: 1974 270

Re: swapping rear axle assembly

Unread postby 77Travco on Tue May 19, 2015 1:35 pm

Keep in mind that a school bus will probably have air brakes. That may be a can of worms that you do not want to open.
I would search local salvage yards for large truck rear ends with hydraulic brakes. Maybe look for a complete truck in order to have access to the entire driveline and other parts.
User avatar
77Travco
Moderator
Moderator
 
Posts: 1141
Joined: Sat Jan 26, 2013 2:32 am
Location: Kerrville, Texas
Travco Model:

Re: swapping rear axle assembly

Unread postby rampeyboy on Tue May 19, 2015 7:35 pm

Was talking to a coworker today about buying a running Dodge diesel dually, and using it as a donor. He says they use a DANA 80 rear axle. It would naturally be geared for the diesel. If the width is right, and it is a beefy enough unit, I could swap it and use the dually wheels and tires on the rear of the Travco, use the dually trans and engine for a "perfect" match...thoughts??

Boyce
rampeyboy
New Member
New Member
 
Posts: 9
Joined: Sun May 17, 2015 12:43 pm
Travco Model: 1974 270

Re: swapping rear axle assembly

Unread postby 77Travco on Thu May 28, 2015 2:55 pm

I suppose it's possible. I would look for a 1.5 ton (or bigger) truck equipped with a straight axle in the front so that you could swap them both. That way you would only need to carry one spare.
User avatar
77Travco
Moderator
Moderator
 
Posts: 1141
Joined: Sat Jan 26, 2013 2:32 am
Location: Kerrville, Texas
Travco Model:

Re: swapping rear axle assembly

Unread postby Psychowolff on Wed Jul 01, 2015 11:49 pm

I have a few questions I cant find an answer to...

If i have a 1990 D350 (5.9 CTD/47RE) with a 70HD 3.07 gears, can those gears be swapped into a 70-72 Travco 70hd 4.56 rear axel? I came across something about a 1/2" or 5/8" 'difference' but they didn't explain it any better, well, that i could understand anyways.

I'd like to do the 5.9 CTD swap someday but was wondering about getting the gears changed now, how would a 440/727 drivetrain work with 3.07 gears?? How badly would the low end torque be effected? Would the lower Hwy RPM's make it worth the decrease in lower end grunt??
Psychowolff
New Member
New Member
 
Posts: 13
Joined: Mon Jun 08, 2015 2:23 am
Travco Model: 70's 210/220/270 aka none yet

Re: swapping rear axle assembly

Unread postby Acesneights on Mon Jul 06, 2015 8:47 pm

PM Jeeprob. he did this swap in his thread. There was something about a spacer IIRC.
1975 Travco 270
1974 Travco 220 Parts unit
User avatar
Acesneights
Site Admin
Site Admin
 
Posts: 1755
Joined: Tue Jan 22, 2013 7:01 am
Location: North East Ct
Travco Model: 1975 270,1974 220

Re: swapping rear axle assembly

Unread postby KB2CRK on Fri Jul 10, 2015 8:18 am

Found this on you tube. How to fit the 3.07 gears in the 70HD.
https://youtu.be/gZguzQX1P2E
User avatar
KB2CRK
Moderator
Moderator
 
Posts: 859
Joined: Wed Nov 19, 2014 2:26 pm
Location: Arnoldsville GA
Travco Model: 76 Mahal 2+2

Re: swapping rear axle assembly

Unread postby 72twodoor270 on Sat Jul 18, 2015 7:21 am

did you do the swap? I have been eying up Isuzu box trucks around here on CL. (Comparable GVWR and widths)

There is a guy in Richmond that has a complete front and rear axle including suspension from a late 90's Isuzu box truck sitting on a pallet. I am seriously thinking that once I have Delia up and running, I may do an axle swap. I have a friend who is into rock crawling and I talked to him about doing the work. he was full of info on it and gave me some links to some rock crawling websites. These guys switch axles like I change oil. I'm thinking as hard as it is to find brake parts and considering my 5 lug split rims and hard to find tires... when you add up all the cost of keeping the Travco on the road an axle swap for less than $1k that provides modern brake systems, modern rims, more choices for rubber, and lots of steering options, it sure gets tempting...?..
User avatar
72twodoor270
Senior Contributor
Senior Contributor
 
Posts: 106
Joined: Thu Jun 18, 2015 12:10 am
Location: Fredericksburg VA
Travco Model: 1972270 commerical travler

Re: swapping rear axle assembly

Unread postby 72twodoor270 on Sat Jul 18, 2015 7:37 am

I like the Isuzu NPR's and such as an option. most seem to be GM platforms, they are comparable in weight/GVWR to 270's and if you can get a complete rig, a diesel engine swap is also an option... But first I have to get mine on the road before I drag anything else home or even better, get mine running and drive it to a friends shop and do the work there!!
User avatar
72twodoor270
Senior Contributor
Senior Contributor
 
Posts: 106
Joined: Thu Jun 18, 2015 12:10 am
Location: Fredericksburg VA
Travco Model: 1972270 commerical travler

Re: swapping rear axle assembly

Unread postby Kckalden on Sat May 21, 2016 7:06 pm

I plan to put a Cummins 5.9 in my 270. Since the rear axle is a concern in have been doing some resurch. The Dana 70hd in the 270 is rated at 10000 lbs the Dana 80 is rated at 11000 lbs. dodge rates the 80 in its pickups a lot less about 7500. Some Dana 80s in dodges pickups are hybrids using Dana 70 parts. I have read inner bearings were from 70s to the entire axle tubes. Anyways they are different. I think the Dana 80 in one tons are true 80s.

The dodge 2nd generations 3500 pickups have a wider axle than the 270 due to the wider frame. the 3500 cab and chassis which has a frame width simular to the 270 it's axle might be a good match with a foot print closer to the 270s.

This gets to the question of brakes. The Dodge 3500 has 13 x 3.5 brake shoes where I believe the Travco has 15 x 4. Is this a stumbling block? Did dodge spec out the Dana 80 with brakes that can't live up to the reputation of beefy Dana 80? I owned a 2001 dodge 3500 cab and chassis. It's brakes sucked. I mean sucked. I sold it because I did not want to kill anyone. That being said I had other dodges hat stopped fine. In 2002 dodge went with disc brakes on the Dana 80. I have yet to resurch the disc brakes.

My next question is what about the front axle? Can I find one with disc brakes and 8 lug wheels and a 4000 lb rating? Where?

Does anyone know the rating of the 17 inch stock tires on the 270? Will a load range e 16 inch tire work as good?

This week I am going to look over a couple freightliner step vans and see if the axles will bolt up with minimal effort. I do think the foot prints will be too wide so finder skirts might be needed.
Kckalden
New Member
New Member
 
Posts: 13
Joined: Sun Apr 10, 2016 10:46 am
Travco Model:

Next

Return to Drivetrain

Who is online

Users browsing this forum: No registered users and 1 guest