Jeep JK Wrangler NSG-370
Manual Transmission Service

As a part of good routine maintenance, it is highly recommended that you service your NSG 370 manual transmission once every 30,000 miles. Changing your Jeep JK Wrangler’s transmission fluid will give you an opportunity to inspect the magnetic drain bolt for any signs of abnormal wear going on inside (i.e. large chunks of metal attached to it) and new fluid will help keep things operating smoothly.

NOTE: It is important to only use MOPAR MS-9224 Manual Transmission Fluid (sometimes listed as NV-3500 Fluid) or equivalent like Syncromesh. Standard gear oils have sulphur in them and damage your synchros.

What You Will Need


(3) Quarts – Mopar MS-9224 Manual Transmission Fluid
• H14 Allen Bit
• H17 Allen Bit Cut Down or
Modified 1/2" Coupling Nut

• 1/2" Drive Ratchet
• 17mm or 11/16" Wrench
• Bottle Pump
• Oil Catch Pan
• Bench Vice
• Die Grinder

What You Will Need
To Make a Drain Plug
Removal Tool


• H17 Bit or 17mm Allen Wrench
• 1/2" Coupling Nut
• Bench Vice
• Die Grinder
• Sawzall w/Metal Cutting Blade

   

Instructions


Making a Drain Plug Removal Tool
I don’t know what Chrysler was thinking when then designed the JK but due to the fact that they routed the exhaust crossover directly underneath the drain bolt on the NSG 370 manual transmission, removing it is somewhat of a challenge especially if you don’t have the right tool to do it. For my purposes, I decided to make my own 17mm removal tool and the instructions below will show you what I did.
1. If you are making your drain plug removal tool out of a 1/2" coupling nut (outside width = 5/8"), you will need to trim about a 1/4" off the end of it so that it’ll measure about 1-1/2" in length. This will make the coupling nut short enough to fit between the exhaust crossover and transmission on your Jeep JK Wrangler.
2. Place the coupling nut into a bench vice and use a die grinder to grind off the excess length. You will also need to grind all 6 sides of the coupling nut just a bit to reduce it’s over all dimension so that that it’s closer to being 17mm.
3. This is a shot of what your new NSG 370 manual transmission drain tool should look like when all is said and done.
NOTE: You can also create a drain plug removal tool by cutting the end off of a 17mm allen wrench or H17 bit.
Servicing Your NSG-370 Manual Transmission
1. Park your Jeep JK Wrangler on level ground. Place an oil catch pan underneath your NSG 370 manual transmission and then, using an H14 allen bit, remove the fill bolt which is located on the passenger side as shown. 2. Maneuver your cut down H17 allen bit or modified coupling nut up between your Jeep JK Wrangler’s exhaust crossover and up into the drain bolt on your NSG 370 manual transmission. Then, using a 17mm or 11/16" wrench, proceed to loosen the bolt until it can be turned by hand. 3. Hold an oil catch pan up close to the exhaust crossover on your Jeep JK Wrangler and then remove the drain bolt completely.
4. The drain bolt on your NSG 370 manual transmission has a tip that is magnetized and as you can see in this pic, it should be covered with small metal filings that stand up like hair. This is normal and will need to be cleaned off before it can be reinstalled. 5. This is a shot of what your NSG 370 manual transmission drain plug should look like once it is clean. 6. Using your cut down H17 allen bit or modified coupling nut and 17mm or 11/16" wrench, reinstall the drain bolt onto your NSG 370 manual transmission.
7. Attach a bottle pump to your Mopar transmission fluid bottle, insert the feeder tube into the side of your NSG 370 manual transmission and then begin pumping the fluid into it. It should take just a tad over 2 quarts of fluid to fill and you’ll know when it’s full when fluid starts to ooze back out the fill hole.
8. Once the fluid starts to ooze back out, quickly reinstall the fill bolt onto the side of your NSG 370 manual transmission using an H14 bit, clean up your mess and you’re done.
If you haven’t done so already, I would highly recommend that you now move over to your NV241 Transfer Case and service it as well. Click on the link below to see a detailed write-up on how to service it:

Jeep JK Wrangler NV241 Transfer Case Service


When finished, please be sure to take your used transmission fluid to your local auto parts store to have it disposed of properly.

40 Comments on Jeep JK Wrangler NSG-370
Manual Transmission Service

  1. I know this seems stupid, but where did you get that bottle pump? I can’t find one at any of my local auto parts sores for a quart. They only have gallon size pumps.

  2. there was no way and inch and half 17mm allen key worked…mine was 3/4 inch….the write up made the whole job possible…..thanks

  3. An easier and more efficient drain hole plug removal tool:

    1) Cheap 17mm (H17) allen socket from Autozone.
    2) Arbor Press

    Place a small socket inside the half inch socket end and press out the hex head. End result is an exact 1 1/2″ 17mm hex head. No machining needed.

    Good write up by the way. Being a new JK owner this made things straight forward.

  4. You make everything simple for non mechanics like me !! Now my JK has auto tranny… can it be done by average owner also ?

  5. My motorcycle has the same drain-over-the-exhaust problem; putting some aluminum foil over the pipe before draining keeps the exhaust pipe clean and avoids the burning-oil smell afterwards.

  6. If your going to cut down a 17mm allen key, cut it to no more than 3/4″.

    This is the longest it can be on my 09 2 door. 1.5″ is WAY to long… i can barely get my thumb turned sideways in between the plug and exhaust.

  7. I don’t have a dealership ANYWHERE near me.
    What other gear oils would you recommend? something I can get at my autoparts store (i have a napa and an oriely)

    Thanks for the writeup.

  8. Just called the stealership and the Mopar Manual Tranny Fluid costs $24.95/qt. I just came back from Advanced Auto where they have Pennzoil Synchromesh MTF with a Chrysler part number on it: MS9224. The price – $7.49/qt. Saved 50 bones.

  9. Just bought a used ‘08 Wrangler Rubicon right at 30K miles – so I was due for all of this. Dealer wanted $240 – mine – less than $90.00. Thanks so much for the clear instructions and pictures. I made both adapters from some Sears Craftsman Wrench Socket adapters (less that $10.00). I had to file the face of all six sides because they were SAE not metric – but it only took 4- 5 strokes on each face to get a perfect metric fit. For the 17MM tight fit drain right above the exhaust – I used a bench grinder and took it down just past the ball bearing detent holder and now if fits perfect. So fun making your own tools. I too used Penzoil Synchromesh from Advance Auto. This Forum ROCKS – thanks much!

  10. I just bought a 2007 Rubicon with 50k miles. I guess I better do this service too. The dealership sold me a vehicle with only 3 qts of motor oil in it, then lied about changing the oil. I hate to see how bad my trans is… Thanks for the sweet write up!

  11. Went with Redline MTL full synthetic totally compatible with MS-9224. Picked it up for $10.00/quart actually cheaper than the Penzoil/Castrol synchromesh at my local autostore! the shifting is amazing no notchiness and the shifts are smooth as silk!

  12. I was WAY due for a rear diff change, transfer case change, and transmission fluid change. I was thinking man…here goes 300 or so bucks.. But, then I found this site. Awesome step-by-step and the gigantic sized pictures say 1000’s of words. Thanks for putting up the site.

  13. I just got done changing my oil and it only took 2 quarts of fluid before it started flowing out of the fill hole, my 2009 jk was on level ground, any reason why this would happen?

  14. Just changed for the first time. Mine also only took 2 quarts. Any word on this? Is it normal? Thank you guys again this site is great.

  15. Great tutorial! Just performed this service yesterday without any issues. I found a hex bit set at Harbor Freight for $12 that included the 14mm and 17mm bits. I put the 17mm hex bit in my bench vise and pounded out the hex portion with a hammer and bolt. I then cut it down to about 3/4″ with my angle grinder. Thanks again for the write-up.

  16. Great write up.

    Another way to make a cheap and easy removal tool it to buy a M10 bolt and two M10 nuts. The M10 bolt has a 17mm Hex head, use two Nuts to lock one against the other on the other end of the bolt, put the head of the bolt in the drain plug and us a 17mm wrench against the Nut to open the plug. Total cost for the M10 Bolt and two M10 nuts USD2 at home depot.

  17. Excellent write ups on both the Transfer Case Service and the NSG-370 Manual Transmission Service. Your write ups are always excellent with great photos. I am right at 30,000 miles and was wanting to jump into changing fluids for both of these, sure am glad I read your writeup first or I would have been frustrated trying to figure out how to get the drain plug out of the NSG-370. I do have one question, do I need to purchase a separate pump for each fluid (MS-9224 and ATF+4)so as to avoid any fluid cross contamination from the residual fluid that may be left in the pump, or can I simply make sure I drain as much out of the pump as I can and that’s good enough?

  18. Thanks for info really helped, had trouble organising gear oil here in Australia.
    2010 jk rubicon 2 door 6″ lift 37’s etc etc keeping it real.

  19. I bought a 17mm allen wrench from Sears and I will use Royal Purple for the re-fill.

    Thanks for the write up.

  20. My girlfriend has a 2005 TJ Wrangler with the 6-speed tranny in it. Are the drain & fill plugs used on the KJ series that requires a H14 & H17 allen bits to R&R, the same as the KJ series? Also, I found Pep Boys and Advance Auto has Penzoil Sychromesh Fluid that meets the Mopar MS 9224 spec and it’s 7.99 per quart @ Advance. Pep Boys has it for $2.00 higher.

    Thank you

  21. Her 2005 TJ aslo has an issue with getting it into reverse gear, any thoughts on that? BTW GREAT STEP BY STEP Instructions on the service procedure above! She doesnt have the crossover exhaust pipe as a result of having the straight 6 banger in the cradle

  22. What JK manual transmission takes 3qts of fluid?

    The dealership says 1.6qts for a 2008 manual transmission.
    Mine took 1.5qts before fluid spilled out the fill tube.

    Would it be worth updating the post to show the correct amount of fluid?

  23. If you read the directions, it specifically states “you’ll know when it’s full when fluid starts to ooze back out the fill hole.” Nowhere on it states you “need” to put 3 quarts in.

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