55 m38a1 rear Diff

theduke · Post by **theduke** » Tue Oct 20, 2015 9:47 pm

I'm New here.

Wes got me on track a few weeks back to finally get my jeep running.

Thank You

I've been scouring every thread in the Tech section.

Up to page 55....been at this a couple few weeks now.

I'm not having any luck at all with the search feature...Not sure why.

So I started at page 1 and ..got another 75 to go. Learned lots.

Many questions but I'll keep this simple.

My 55 m38a1....Pretty much as it came from the factory. No Civillian crap at all. What little there was is gone. Its all Green ( hints of white in grill)

It Has a 41 rear differential.

Is this correct?

I have several 44's and would rather have one of them in it but ...it works fine and has new brakes ( previous owner install).

Leave it alone or upgrade?

Dan in Oregon

Yes I will update profile with serial #...my bad.

Found plate behind rear pass. seat with 20 coats of paint on it.
Not sure how to Best..Not F it up & retrieve #'s from it...waiting on best answer besides dot3 fluid.

FactoryDash mounted Data plate..which looks to be UnMolested shows...

........................................................82952
........................................................3/55
( a Eagle symbol w/3 stars above it ) &..... EPM

Till I can confirm the rear plate #'s....I do not know if this is correct for the/my JeeP.

Bretto · Post by **Bretto** » Wed Oct 21, 2015 5:12 am

Dana 44 would be the correct axle, with 5.38 gearing.

Thunderbird712 · Post by **Thunderbird712** » Wed Oct 21, 2015 7:00 am

Another way to search is to use Google. So for example you can search "M38A1 rear differential willysmjeeps." This will provide links to most of the threads on the website and other sources of information. Although sometimes going page by page here is good as well.

4x4M38 · Post by **4x4M38** » Wed Oct 21, 2015 7:35 am

Hello Dan,
Don't use the search to the left on the front page.
Use the search in the horizontal list of picks just
under the title at the top.

Not sure what's up with the one at the left but it just doesn't
work properly. Maybe Wes or Ryan can get it removed.

Brian

4x4M38 · Post by **4x4M38** » Wed Oct 21, 2015 7:39 am

Using the above search button with "M38A1 rear differential"
I get the following:
http://www.willysmjeeps.com/v2/modules. ... de=results

I would assume the differential information would also
be in the M38 manuals free for download here.

Xamon · Post by **Xamon** » Wed Oct 21, 2015 7:50 am

Dot3 really is the best stripper for the data plate, many paint strippers will eat aluminum.

theduke · Post by **theduke** » Wed Oct 21, 2015 8:43 pm

Bretto wrote:Dana 44 would be the correct axle, with 5.38 gearing.

This was my thought also......But

I crawled under thr jeep and did a thorough inspection for signs of replacement.

What I found:
Factory brake line support @ 10 o'clock...2 bolt bracket.
Factory brakeline clip @ 1 o'clockish
Factory gear ratio tag 43/8 @ 2 o'clock

U bolts show a bit more thread exposed on one end of each yet its all in a uniform pattern.

Lack of any brake line clips mounted to axle tubes?? Not sure if there should have been but other axels I own have these.

Brake lines are mostly the correct shape...short side is a bit out of place but easily explained to backing plate removeal or some random branch grabbing it.

It sure seems that this Rear Diff has spent some time in this jeep.
Tags on front axle match exactly.

In the interest of thinking Outside the norm ......Is it possible that this IS the factory rear Diff..OR were 41's only used on some specific Model?? & Year?

4x4M38 wrote:Hello Dan,
Don't use the search to the left on the front page.
Use the search in the horizontal list of picks just
under the title at the top.

Not sure what's up with the one at the left but it just doesn't
work properly. Maybe Wes or Ryan can get it removed.

Brian

Thank You....It took the better part of today to Finally find the word "search" where you described it..... DUH..Its right there....I will try that one Now.

Xamon wrote:Dot3 really is the best stripper for the data plate, many paint strippers will eat aluminum.

Is there a simple proven Method of useing BF ?

I see NO indents on the back of the small plate>

I've read the #'s are Etched in the plate and I've seen pics of what is under the paint.

I just have one shot @ getting it right.

If I Knew or could read the #'s from the backside ..I'd leave the paint on it & screw it back on.

Post by **wesk** » Wed Oct 21, 2015 9:06 pm

41's were not used after about 1951. On a 60 year old jeep a lot of parts will look like they spent a lot of time on the jeep. A 44 is correct for your M38A1. The fact that tags and brake line clips went from the original 44 to the 41 on there now just means the own at the time of the swap moved some original parts to the new axle.

4x4M38 · Post by **4x4M38** » Wed Oct 21, 2015 9:17 pm

Put the plates in a plastic tray and pour the brake fluid in and cover.
If you can place them so the fluid can get to all surfaces.

24 hours should be sufficient but more layers will take longer

The bf won't hurt the plates at all.

You can use an old toothbrush to scrub

theduke · Post by **theduke** » Wed Oct 21, 2015 11:21 pm

Thank You Wes...on the 41 info.

This starts a whole new batch of decision making.

I have 2 0r 3 correct housings and axles of various splines...I have owned several jeeps...a whole other topic.

I also have a Freshly built 44 rear with 5.38's and an ARB air locker & the discontinued I believe? Warn Locking hubs and 11" drums. Also have the Nearly Exact Front end built but is a 30 and 3" wider. Its a Disk Brake set up.
These were built for my V8 Samurai but went with a spooled 44 rear air locked front & 4.88's.

Soo

Swap in an older factory 44...That I'll have to buy yet another set of gears/bearings & air locker?
Or
Put in the one sitting here. It is Tow friendly with the Locking Hubs on rear.

It will be spring under like the stock one.....My jeep is a Driver but I have no interest in lift or any of that BS. Already have way too many Big Trucks.

and then I'd want the matching front end installed.........

Not gonna happen easily...too wide...wrong tie rod sytem & I'd have to /want too have power steering.
A whole new nightmare....I refuse to even consider a saginaw scab job.
I have entertained a celica box or tracker...its just so tight of an area to work with having the fuel pump/exhaust/radiater in all the possible areas for a different steering box.......Not going there...I want to keep it in use now that its finally running reliably.

OR

Leave it as is and run it till ..well maybe forever.
While not correct it functions fine so far.

Jeep looks like it just came back from wherever/whatever War it was & thats the look I want.

I don't even want to wash it!

Pedestal mount just arrived and the M37 will be in place soon.

Previous owner rebuilt Motor/Trans...Brakes..New NDCC's x5..New canvas...and new seats.+ what I forgot.

Pretty good start. Its been here 4 yrs and finally is on the front burner.
Way too many projects.

I will give this BF a shot & see what my lucky # is.

Dan in Oregon

Bretto · Post by **Bretto** » Thu Oct 22, 2015 5:10 am

We are going to require pictures brother. Where at in NW Oregon? If its up to me, I'll be living up there someday.

theduke · Post by **theduke** » Fri Oct 23, 2015 3:22 pm

Heres a few quick pics I found.
Will try to get a few more up.

A couple from the Museum in HoodRiver , OR

You'll like this one

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