Complete Transmission Assembly (4-134 engine)
Fits 41-45 MB, GPW with T-84 Transmission

Complete Transmission Assembly (4-134 engine)
Fits 41-45 MB, GPW with T-84 Transmission

Complete Transmission Assembly


Everything you need to completely redo your entire transmission already assembled Kit includes all New gears, shafts, bearings, syncronizer, snap rings, thrust washers, & roller bearings. Its complete and already assembled. Just drop it in! Its even assembled here in the USA!!!

Helpful Guides and Illustrations:
Replacement Instructions

T-84 Transmission with 4-134 engine

41-45 MB
41-45 GPW

Customers old transmission, transfer case and top shifter must be picked up prior to ordering.

Please allow 5-6 weeks for delivery.

Item # Price

Product Videos

Questions & Answers

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Questions: I sent my complete Willy’s MB transmission and transfer case to KWs for a total rebuild, as it would not stay in second, or shift to first / reverse with out stopping and shutting down the ignition. 3 weeks later, i got it back with all new parts, totally re built and re assembled, via air freight ( so normal trucking companies would not damage it in transit) I installed it over the next few days, and have now taken her for a test drive. She shifts perfectly, both up and down, does not leak, shifts easily from a full stop into first or reverse. This is just one more easy step to restoring mt 78 year old girl for another 78 years. Round trip shipping was included, as were all new shafts and gears, and bearings and synchros...what could be better! ,
Question By: Paul A. Kalenian on Dec 23 2020 10:33 PM
Thanks for the positive feedback!!!
Answer By: WIllys Jeep Parts Tech on Dec 28 2020 6:13 AM
Questions: I have a T-84 transmission that I took apart cleaned and was intending to re-build. Now I am leaning to buying on completed. Can I swap all the parts dis-assembled when I purchased the re-built trans?
Question By: Edgar Hall on Apr 7 2019 11:51 PM
If your old transmission has already been dis assembled, that is fine. We will still take as a core.
Answer By: Willys Jeep Parts Tech on Apr 8 2019 5:37 AM
Questions: I just bought a '42 mb and it has a T90 transmission in it. All things equal and working, should I keep this transmission in it or trade it out for a T84? I plan on using the mb for fun and hunting instead of buying a side by side quad.
Question By: Frank on Nov 20 2018 10:35 PM
We can help you out either way. Please call me toll free. Ask for Mike M. Happy to help.
Answer By: Willys Jeep Parts Tech on Nov 21 2018 6:20 AM
Questions: I am looking to purchase this for a friend who is restoring a 1943 Willys in France. Although I am located in California I was wondering if you would be able to ship directly to France and whether you were familiar with the import duties there. Please let me know thanks.
Question By: Norman Bellil on Sep 5 2018 6:35 PM
We really need your old T84 in and your Dana 18 transfer case. Email and I can help out.
Answer By: Willys Jeep Parts Tech on Sep 6 2018 5:40 AM
Questions: Which grade of trans/transf case gear lube is best for a 42 GPW? Should I use a GL-4 or a GL-5 80/90 lube. the former owner used GL-5 80/90 thanks.......
Question By: Phil Lauricella on Jun 3 2018 10:16 PM
We use a straight GL-4 non synthetic. They are good for yellow metals.
Answer By: Willys Jeep Parts Tech on Jun 4 2018 5:57 AM
Questions: I have a restored 42 Willys MB. Transmission was making noise in 2nd gear. A mechanic sent the transmission to transmission shop and they said they had to build up the main shaft and turn it down. Now it makes severe noise in 3rd gear at all speeds. I complained and they sent the transmission back and said it was normal. I have owned several Willys Jeeps, this does not seem right. I have been out some serious money allready. What do you guys suggest. Thank you, Ralph Todd
Question By: Ralph Todd on Mar 14 2018 12:46 AM
Doesnt sound right to me. Some gear chatter is normal in the transmission and transfer case but from what you write that sounds excessive. Call me toll free. Ask for Mike M. I can try to help out.
Answer By: Willys Jeep Parts Tech on Mar 14 2018 6:27 AM
Questions: Do you have the GPW t84 case as well or are they all MB.
Question By: Richard Lanoix on Feb 15 2017 6:45 PM
We may be able to source one for you. Please call us toll free.
Answer By: Willys Jeep Parts Tech on Feb 15 2017 11:10 AM
Questions: Does the t-84 and t-90 use the same transfer case ? I just bought an mb frame and motor i put a t-90 trans to the back and its 1 1/2 inches to long if i get a t-84 trans will it work with the transfer case i have ?
Question By: Bill on Sep 21 2014 12:00 AM
No, the transfercase between the two are different. T-84 used a 3/4 intermediate shaft and the T90 used either a 1-l/8 or 1-1/4 intermediate shaft all with different gears from one another. This link will help:
Answer By: Willys Tech on Jan 1 1970 12:00 AM
Questions: I have a 45 gpw that has a t90 swap. I am doing a frame off restoration And would like to go back to a t84 so I don't have to cut the floor. What are the dimensions of the t84 vs t90?
Question By: Travis on Jun 28 2014 12:00 AM
The T84 sits lower than the T90 because of the top shifter. I imagine that someone had to cut your floor board to make the T90 work in your jeep.
Answer By: Willys Tech on Jun 30 2014 12:00 AM
Questions: On my t-84 transmission, it won't shift into first gear while vehicle is in motion. Is this normal or do I have a problem?
Question By: Steve on Nov 4 2013 12:00 AM
You shouldnt be able to. It is not sycronized.
Answer By: Willys Tech on Nov 4 2013 12:00 AM
Questions: I'm weighing in the option of picking it up or shipping it overseas. What is the weight and dimension of the package to be shipped; and will be packed into a wooden crate?
Question By: Alex on Aug 14 2013 12:00 AM
These come in a heavy duty double walled box with packaging. The box is approx 18x12x12 and weights 50 pounds.
Answer By: Willys Tech on Aug 14 2013 12:00 AM