OVERDRIVE

1941 - 1945, MB, GPW modifications, sugestions, and ideas, official MWO's and unofficial WWII field mods NO EBAY or COMMERCIAL SALES.
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OldGPW
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Re: OVERDRIVE

Post by OldGPW » Mon Nov 15, 2010 4:10 pm

Look forward to photos.

Keep us updated on the oil loss.
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Jon S
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Re: OVERDRIVE

Post by Jon S » Mon Nov 15, 2010 10:33 pm

Marty, thanks for posting this!! I am a purist, but I am in the midst of planning a very long trip in the MB... I now think that an overdrive may be the way to go. I like the clean way that you installed it and also the fact that you can reverse the process and have a stock jeep again if you want... I am also thinking about using my Kaiser Supersonic head on the engine to help out a little... Do you think it would boost the performance a little?
Thanks for all your technical work on this!! I want to copy the way you installed the unit!!! Very SANO!! Jon S.
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Re: OVERDRIVE

Post by Marty, SoCal » Sat Nov 20, 2010 5:53 am

Thanks for the compliments!

Jon S., The higher compression Supersonic head should help! Be sure to use the later, gear drive head gasket as the combustion chamber shape is different than a chain drive head. Fel Pro sells both styles, the # 7285B is the correct one for the gear drive head and costs about $15 at O'Reillys. http://www.oreillyauto.com/site/c/searc ... vi=1440562" onclick="window.open(this.href);return false;

If you decide to copy the shifter setup I used, the longer shifter pin can be easily made without a lathe, all it really needs is a groove or notch for the set screw to hold it in place, a file will cut one easily. The local hardware store will have 1/2" diameter cold rolled steel round rod to make it with. It doesn't really need to be drilled for a grease fitting, you could simply oil the pin occasionally from below with a spray lube. I'll see if I can take a picture or scan of my shifter boot retaining ring set on a piece of 1/4" graph paper to make a copy of one a bit easier.

OldGPW, About two months ago I installed an overdrive in my friend's 44 MB, in the same way as the post. We got it from Herm the Overdrive guy, too. When I put it in, I used a double rubber sealed rear output bearing on the T-84, and sealed the gaps in the splines and around the bearing itself with RTV sealer. He hasn't taken it on any long trips at high speed yet, but driving it around town and in the desert, it didn't leak. With the stock, non-sealed bearing, it would transfer oil from the t-case into the trans and leak while driving it around town. The local O'Reilly's had the # 307FF bearing in stock!
http://www.oreillyauto.com/site/c/detai ... word=307ff" onclick="window.open(this.href);return false;

I've not gotten around to changing it on mine, yet! :roll:
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Re: OVERDRIVE

Post by cjv-35 » Sat Nov 20, 2010 9:51 am

I have a super sonic head in my cjv-35.Great addition.Also stronger with the addtional ribs between the spark plug holes.Very nice looking set up Marty.What is your final gear ratio in third overdrive?Artificer has a point about the windshield.In my estimation,that's probably why willys went to the rectangular windshield on the cj-3a.3b,m-38 jeeps.Stronger than the tube type of mb,gpw,cj-2a. :D

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Re: OVERDRIVE

Post by Marty, SoCal » Sun Nov 21, 2010 9:58 am

cjv-35 The .75 ratio is equal to having 3.73 gears while in overdrive, compared to stock 4.88s. On a CJ or M38 with 5.38s, it would make it the approximate equal of 4.10s.

Here's a link to one online ratio/speed calculator: http://www.public.asu.edu/~grover/willys/speed.html" onclick="window.open(this.href);return false;

Here's a pic of me at speed on the 10 Freeway near the Morongo Casino!

Image

Here's a link to my Photobucket trip album:
http://s551.photobucket.com/albums/ii47 ... th%202010/" onclick="window.open(this.href);return false;
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Re: OVERDRIVE

Post by cjv-35 » Sun Nov 21, 2010 4:33 pm

That sounds like GREAT freeway gears to me.The L-4 should not be over revving with that ratio.Great looking picture of the beast on the freeway.I installed a warn overdrive in my cjv-35 way back in 1978 when I purchase my jeep.Best thing I ever did.I took it up to 70 mph for no more than 1/2 mile.WOW,enough of that.Best speed for me is 50mph.Take care. :D

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Re: OVERDRIVE

Post by cjv-35 » Sun Nov 21, 2010 4:55 pm

Finally got your pictures from your trip to come up on my dial-up.Your jeep looks the BEST of all of them. :D

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Re: OVERDRIVE

Post by Cacti_Ken » Mon Apr 04, 2011 7:53 pm

great photos. I guess I'll have to move to another location if I want to have fun with my jeep.
I put a overdrive unit in my M38. I went for a drive last month for 88 miles and used 3.5 gallons of gas. I thought that was pretty good.
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Re: OVERDRIVE

Post by OldGPW » Mon Apr 04, 2011 8:00 pm

Marty, SoCal wrote: OldGPW, About two months ago I installed an overdrive in my friend's 44 MB, in the same way as the post. We got it from Herm the Overdrive guy, too. When I put it in, I used a double rubber sealed rear output bearing on the T-84, and sealed the gaps in the splines and around the bearing itself with RTV sealer. He hasn't taken it on any long trips at high speed yet, but driving it around town and in the desert, it didn't leak. With the stock, non-sealed bearing, it would transfer oil from the t-case into the trans and leak while driving it around town. The local O'Reilly's had the # 307FF bearing in stock!
http://www.oreillyauto.com/site/c/detai ... word=307ff" onclick="window.open(this.href);return false;

I've not gotten around to changing it on mine, yet! :roll:
Marty, just saw the reply (somehow I missed it!). That is VERY good to know, I'm probably going to pick one of these up and this thread has been a great help in getting me interested in actually doing it!

Thanks for the update. 8)
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Re: OVERDRIVE

Post by Marty, SoCal » Sun May 01, 2011 10:25 am

I finally got around to changing to the sealed bearing, and this time I took some pics! I posted it in the regular MB/GPW Technical forum, here's a link:

http://www.g503.com/forums/viewtopic.php?f=4&t=183156" onclick="window.open(this.href);return false;
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Re: OVERDRIVE

Post by artificer » Sun May 01, 2011 1:33 pm

Marty said: On both jeeps, the oil transferring got worse after installing Warn Overdrives, probably from being driven at higher speeds.
Add a 3rd jeep with Overdrive....just doing mine now plus modifying the breather.

Toyota have same oil transfer issues & apparently the t/f case fill plug & tranny fill plug are interconnected by tubing to alleviate the problem, I saw somewhere on a forum.

Also found out the new flange/s (from reputable sources) fitted to rear transfer case is shorter than the originals so a shim of about 1/16" needs to be fitted between flange & bearing otherwise the washer & nut bottom out on the splines instead of pulling up tight. Easily missed on assembling & torquing in situ.
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Re: OVERDRIVE

Post by Cacti_Ken » Sun May 01, 2011 4:57 pm

[/quote] Also found out the new flange/s (from reputable sources) fitted to rear transfer case is shorter than the originals so a shim of about 1/16" needs to be fitted between flange & bearing otherwise the washer & nut bottom out on the splines instead of pulling up tight. Easily missed on assembling & torquing in situ.[/quote]

I got short yoke a few months ago. I don't know what the manufacturer's problem is. Obviously cutting to the wrong specs. The vendors need to send them all back and make them get it right. Where ya gonna come up with the correct shim washer when your trying to finish the job when your not aware that you got a mismanufactured part shaft all of a sudden.
I sent the yoke back for the correct one. And they found one and sent it to me.
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Re: OVERDRIVE

Post by pecopfc » Wed May 18, 2011 2:30 am

WOW, is there anything that can't be done to the AAW! Great Job!
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Re: OVERDRIVE

Post by artificer » Wed May 18, 2011 11:45 pm

Here is how one can mount up a rear overdrive lever by mounting an old transfer case lever where you can just drop your left hand straight on for changing range.
Just drill appropriate hole in the lever flat that normally fits the shifter slot & away you go....correct length threaded rod with locknuts & a couple of heim/rose joints. Very EZ & doesn't look out of place. In case one asks this has been in use for over 12 mo. & that is the fuel line run across the top (1.5" or 35mm clearance), which is going to be moved one day.
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John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: OVERDRIVE

Post by Marty, SoCal » Thu May 19, 2011 11:37 am

Looks like the best way to connect the rear shifted Warn overdrive unit! Looks like you used a stock T84 leather shifter boot and floor ring, too.
43 Ford GPW 92098
53 Dunbar Kapple M100
Sold: 61 CJ-5, 41 T207 WC-1 Dodge closed cab pickup
MVPA #8266
USMC Tanker (1811, 1812), 85-93
ASE Automotive Master tech, former Chrysler-Jeep Level 4 Mastertech, CA state EA smog license


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