D35 replace? Instead of rehab

[pizzatree]

Have a 2wd auto that we use for periodically hauling brush to dump and bikes to trails - some gravel roads but nothing crazy.  We’re happy with it as is and are not mechanics but do wrench what we can, so….

Mechanic has told us we have a few issues to address - rear diff is leaking and likely needs bearings, rear wheel cylinders and rear axle seals are leaking. Quoted us a rough 1200 but that was before he’d looked up our specific model.

 

I know we’ve got a D35 3.55 gearing and from reading on here I’m wondering if it’s worth it to have him rehab all of this or try to swap in something else (8.25)?   We don’t really NEED an upgrade or lift, we’re happy with the mj as is.  Again mechanic would be doing all this as it’s out of our comfort zone.  
 

Any thoughts based on our setup and needs?

 

[Minuit]

First off, are you hearing noise from the rear of the truck?

[pizzatree]

Yep, whirring/metal on metal from rear

[OldManComanche]

Can you verify where it is leaking? Seal behind the U joint yolk, rear diff cover, rear axle seals, or wheel cylinders? Pull the rear brake drums off and have a look.

Are you loosing brake fluid? 

See if you can tell what is actually bad.

None of these are major jobs, It could be time for you to spread your wings and fly!

[Pete M]

this is probably not wise advice for a daily driver, but for an occasional dump run truck, keep it topped off with gear oil and you might be surprised how long it'll keep going.  

[pizzatree]

Thanks for the encouragement!

The brakes are very soft - mechanic wanted to address these to pass inspection. 
We’re picking it up today and will be doing track bar and tie rod end at home and trying to make a decision about the axle/brakes.  Planning to get underneath, pull brakes and get a better idea of what’s going on.  But according to the shop - rear diff cover, rear axle seals, AND wheel cylinders are all leaking. 

[Pete M]

MJs have a special bleeding procedure.  if you don't follow it exactly, you can get air trapped in the emergency line.  you can find it in the link in my signature.  

[ghetdjc320]

I don’t know how much it it for just the axle portion of the quote but brakes should be pretty cheap. Let’s say it’s $200 for brakes (which is very high). That would leave $1000 for an axle rebuild. That’s not a regear mind you but just a R&R of what’s there. Imho that is extremely expensive. If the leak is that bad than you probably wouldn’t be leaking any more as the fluid would have run out. At most shops (although it depends a lot on where you live) they charge a few hundred for a gear swap. Which is a lot more work than replacing bearings and seals.

[pizzatree]

This has quickly turned into a list of things to do myself!
On the list - Tie Rod End, Track Bar, Rear brake wheel cylinders and bleed (those all seem within my capabilities)

Should I plan to rebuild the rear brakes completely with new drums, shoes, everything while I’m in there?

 

Mechanic I talked to yesterday tried to talk me out of a gear swap. “Things don’t ever match up and you’ll always have trouble”

We’re leaning towards getting the brakes firm again and topping off gear oil until we can find a shop that’ll do a swap of D35 for 8.25.

Would 8.25 be the most logical axle to go with - easy to find and give us a bit more reliability? As long as we match current gearing a shop would need to weld new perches and shorten driveshaft for it to fit?
 

 

 

[Andy in Pa]

I JUST pulled a D35 from my MJ to swap in an 8.25.  Its sitting in my driveway. about 1-1/2 hours east of you in Downingtown, Pa.  It has 3.07 gears, but in your case, since its 2wd, it won't matter.  I am converting a 2wd 5 spd MJ to 4wd.

 

You can have the D35, its from an 89 MJ and will swap right in.  No leaks whatsoever, and was smooth and quiet.

 

Let me know if your interested.  Brakes are all dis-assembled right now, but I had rebuilt them with new parts and they worked fine.

 

A. 

[pizzatree]

20 hours ago, Andy in Pa said:

I JUST pulled a D35 from my MJ to swap in an 8.25.  Its sitting in my driveway. about 1-1/2 hours east of you in Downingtown, Pa.  It has 3.07 gears, but in your case, since its 2wd, it won't matter.  I am converting a 2wd 5 spd MJ to 4wd.

 

You can have the D35, its from an 89 MJ and will swap right in.  No leaks whatsoever, and was smooth and quiet.

 

Let me know if your interested.  Brakes are all dis-assembled right now, but I had rebuilt them with new parts and they worked fine.

 

A. 

Thanks for the offer!

 

Would I notice a difference in the gearing?  I’m running 235/15’s and was under the impression that with those tires I’d notice a difference in gearing. I do drive regularly on the highway. Would the 3.07 feel extra sluggish?

Found a good 8.25 (with 3.55 gearing) 1/2 hr away for $150.  
Already bought parts to rebuild the brakes.

 

Now to decide - swap D35 for D35, do brakes and top-off or upgrade to 8.25 (and deal with headache of finding welder and shop)? 
would rather do things on the cheap end but money isn’t a huge issue, would mostly like to make a sound choice for the longevity and enjoyment of the truck. 
 

 

[Andy in Pa]

4 hours ago, pizzatree said:

Thanks for the offer!

 

Would I notice a difference in the gearing?  I’m running 235/15’s and was under the impression that with those tires I’d notice a difference in gearing. I do drive regularly on the highway. Would the 3.07 feel extra sluggish?

Found a good 8.25 (with 3.55 gearing) 1/2 hr away for $150.  
Already bought parts to rebuild the brakes.

 

Now to decide - swap D35 for D35, do brakes and top-off or upgrade to 8.25 (and deal with headache of finding welder and shop)? 
would rather do things on the cheap end but money isn’t a huge issue, would mostly like to make a sound choice for the longevity and enjoyment of the truck. 
 

Honestly, you will probably hardly notice the gear difference with an auto.  Usually gear changes are noticeable with a 5spd manual, or a larger jump, like going form 3.55's to 4.56's.

 

4 hours ago, pizzatree said: