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Shop Kaiser Willys

Replacement Saturn Overdrive Kit
Fits 41-71 Jeep & Willys


New Replacement Overdrive

Comes complete with shifter and everything you need for install. This all-range overdrive is a great addition to any of the early model Jeeps from 1940 to 1971. The addition of this 25% overdrive unit offers you the needed gearing the early Jeeps were lacking.

The Saturn overdrive is a fully synchronized unit that can be shifted-on-the-fly. When installing the unit, only minor modifications are required to the floorboard for the shifter. The Saturn is built to handle up to 300 ft./lbs. of torque, well within the range of a stock V8.

The Saturn is the original unit designed and developed by Warn Industries. The units were offered with 6 splines and either 26, 27 or 29 tooth output gear.

The Saturn overdrive installs directly on the backside of the transfer case through the inspection cover. No cutting or modification of the drivetrain is required. No relays and electrical connections required.

Please allow 6-8 weeks for us to ship these out from time of order

Helpful Guides and Illustrations:
Installation Guide

41-45 MB
41-45 GPW
46-49 CJ-2A
49-53 CJ-3A
53-64 CJ-3B
55-71 CJ-5
50-52 M38
52-66 M38A1
46-64 Truck
46-64 Station Wagon

To determine your tooth count - remove the round access cover on the back drivers side of the Transfer Case and count the number of teeth on the main driver gear.

Options are:
41-46 MB, GPW, 2A: 27 Teeth
46-53 CJ-2A, 3A, M38, Truck, Station Wagon: 26 Teeth
53-71 CJ-3B, 5, M38A1, Truck, Station Wagon: 29 Teeth

Part # Price





Tooth Count
Call for Details

Questions & Answers

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Do you sell parts for the Saturn overdrive? I need part # 911806 & 911236.

Willys Jeep Parts Tech:
Please give us a call and ask for Mike M, we can try to help you.

What is the weight of the package, to calculate shipping?

Willys Jeep Parts Tech:
Please email

If i have the 29 tooth overdrive what will be my top speed with a stock willys cj 2a? And dous my fuel usage go down at cuisine speed?

Willys Jeep Parts Tech:
Typically on a 2A its a 26 but it may have swapped. Basically you'll get 25% more top end. Thanks!

Will the Saturn overdrive work on a 1957 Fc 170? Thank you Chris

Willys Jeep Parts Tech:
Sure, as long as you have the Dana 18 and know your tooth count on the output shaft gear.

Does this kit include the shift lever boots and bracket as shown in the photos?

Willys Jeep Parts Tech:
Everything in the photo will come with the kit.

Is this a new or refurbished unit? I only ask because your price is substantially lower than the list price for a Saturn at other retailers.

Willys Jeep Parts Tech:
These are new.

I have a T14 transmission, 10 spline shaft, connected to a Buick 225. I pulled the main drive gear (29 tooth). When I go to order the overdrive, how do I ensure that I get a 29 tooth, 10 spline drive shaft compatible overdrive? I was referred to Advance Adapters when I called customer service and they confirmed that there are both six and ten spline 29 tooth gears. The drop down on the ordering page only refers to tooth count, but does not refer to spline count. Can you confirm that ordering the 29 tooth model overdrive will fit on the 10 spline shaft? It looks like it should be part # 915674 per the installation instructions.

Willys Jeep Parts Tech:
Email me and we can confirm all for you.

1948 CJ2A, cruise speed with overdrive unit ?

Willys Jeep Parts Tech:
You get 25% more top end. So figure if you can cruise around 45 you should be able to run 55 comfortably.

I have a 53 wagon with F134 and 538 axle gears , how much speed would I gain with an overdrive unit

Willys Jeep Parts Tech.:
You get approx 25% more top end with the SATURN.

removing overdrive unit due to failure, it has a 26 tooth main gear. can i replace with original 29 tooth main gear on dana 18 transfer case

Willys Jeep Parts Tech.:
You have to stock with the same tooth count so the gears mesh.

I have a 53 wagon with F134 and I believe 588 gears, what will overdrive do for me

Willys Jeep Parts Tech.:
In 1953 you typically would be 29 tooth but its best to count.

Will this work with a 4-speed T-98 transmission and Dana 18?

Willys Jeep Parts Tech:
I do not believe it will.

I have a cj2a with a Buick 3.8L V6 mated to a Ford top loader 4 speed, and the original (rebuilt) D18 transfer case - all working great. I am guessing that the overdrive would work, and that the transmission itself would not make any difference. Am I guessing it right?

Willys Jeep Parts Tech:
It may make a difference given the unoriginal transmission and the mainshaft coming out of it. Please email to help.

Hello, Do you sell just the shifter for the Saturn overdrive? Thanks, Al

Willys Jeep Parts Tech:
Email to help.

I have a 53 wagon it has a 327 Chevy with a sm420 transmission it still has the original tcase with the 26tooth main gear, will this still work on it? will the transmission interfere with the mounting of the shifter?

Willys Jeep Parts Tech:
Due to the main shaft on that transmission it would be different I would think.

Do you have a shift shaft seal available for this?

Willys Jeep Parts Tech:
Email about what overdrive you currently have and we can help.

Hi Mike, The planetary is the right one. Looks the same as the main gear I removed. But the planetary does not want to fit. How much force does to need ?

Willys Jeep Parts Tech:
Not sure what you have in there currently. Email to help.

Will this work with a Dana 20 connected to a TH400 automatic transmission?

Willys Jeep Parts Tech:
Sorry, it will not. D18 only.

Do you know how far the overdrive sticks out the back of the transfer case? I am fitting an exhaust and want to allow clearance for buying one of these later. Cheers.

Willys Jeep Parts Tech:
It is 3" at case and rear cone overall length from D18 is 5" altogether.

I have a stock 52 wagon 4wd (has been converted to 12 volt). It has a stock front winch. Does the winch install eliminate the ability to install the Saturn overdraw unit. And how much increase in cruising speed will that provide. Only 5 mph as I have seen in some emails?

Willys Jeep Parts Tech:
See part number A1501. You basically get 25% more top end out of your vehicle. Its like adding an extra gear to it.

How do you count the teeth

Willys Jeep Parts Tech:
Take the access cover off the back of the drivers side of your transfer case (its round) and count the number of teeth there on your main shaft gear.

Does it come with the brown leather shifter covers ?

Willys Jeep Parts Tech:
Black rubber

Do you have a round knob that would fit the shift lever? the kit i recived had a flared flat top knob and i would rather a round one if possible.

Willys Jeep Parts Tech:
Sorry, just that style knob

Will this work in my 68 commando?

Willys Jeep Parts Tech:
Please email on and we can help. Need more information from you.

Turns out my gear is gone, the o.d. burnt up due to an oil leak. Ive read here in the questions it looks like 29 is the one i need?

Willys Jeep Parts Tech:
Email some more vehicle information and we can help.

I keep counting 30 teeth on my gear, am I missing something? Could I be on the wrong gear? It's a 61 m38a with the stock 4 spd and T-18 transfer case.

Willys Jeep Parts Tech:
That would have a D18 transfer case and T90 3 speed. Email to help.

I have a '52 M38A1. I pulled the rear plat and counted teeth. I have 6 inside and 26 outside. Wanting to make sure which one to order.

Willys Jeep Parts Tech:
Yes, then the 26 tooth is the one for you.

CJ-3B -will my T98 transfer case work with the T-90 Transmission? And will you take a t-98 core for the core on a T-90 traanny?

Willys Jeep Parts Tech:
You would have a D18 transfer case. Please call and ask for Mike M. and we can help. Thanks!

Hi Mike, I have a 62 Willys Truck with Ford 250, C4 auto transmission and a tranfer case. Will the overdrive work in my truck ? Peter N

Willys Jeep Parts Tech:
Sorry, no. this is for the T90 transmission with D18 transfer case they originally used.

Can I add a overdrive to a FC 170 that have stock transmission t 90. Do I need any extra hardware or modifications?

Willys Jeep Parts Tech:
Due to the FC design I do believe you will run into fitment issues.

I'm considering replacing my D18 transfer case, could I get it with the overdrive already installed? Would you be open to a better discount for buying both?

Willys Jeep Parts Tech:
You would just have to bolt it up after. Give us a call toll free. Happy to help out. Thanks!

I have 71 CJ5 that has a Locar Automatic Transmission. T18 transfer case. 232 Dauntless V6. Will this work for me?

Willys Jeep Parts Tech:
Sorry, not with that automatic.

I have a 1960 Willy's CJ5, with PTO installed. Can I add the overdrive, or does having the PTO mean I cannot?

Willys Jeep Parts Tech:
See part number: A1501

I have a 1960 Willy's CJ%, with PTO installed. Can you install the overdrive with a PTO already installed? Also, what is the tooth count for a 1960 CJ5?

Willys Jeep Parts Tech:
See part number: A1501 You would be 29 tooth in that year.

I bought the overdrive unit maybe 10-12 years ago and never put it in because I went to South America. I have time to do it now. Is a three-hole boot available for the unit? The boot that I received with the unit is just a flat piece of rubber.

Willys Jeep Parts Tech:
These come with a boot. Please email and we can try to help.

I have a 58 cj5 how do you know what gear and spline to order

Willys Jeep Parts Tech:
1958 Should be the 29 tooth. Just take the access cover off the back of your transfer case on the drivers side (its only 6 bolts) and count the number of teeth on the gear there.

on the options list are they correct on the teeth count

Willys Jeep Parts Tech:
Yes, these are the options for the teeth count. Thanks

What is overdrive going to do for me? I have what is supposed to be a 61 CJ5 with 4cyl. F Head engine.

Willys Jeep Parts Tech:
It will give you about 25% more top speed helping you go about 5-8 more mph. Thanks

I assume the shifter is the one for a two lever transfercase? I see Advanced adapters also shows one for a single lever transfercase

Willys Jeep Parts Tech:
This is for a twin and single stick Dana 18 transfer case.
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