View Full Version : QTI to QTII gear swap help
I have the 3.7L with the 3.07 gears. I was wonderin' where I could get the gears to do a swap for the QTII gearing. I have a friend who works at an offroad jeep shop who could most likely install the gears for me. My only breaking point is price, so hopefully without having to pay for an install, it won't be too pricey.
Thanks, Ross
Sal-XK
08-11-2011, 03:25 PM
As far as I know there are no aftermarket gears made. You would have to purchase the gears from Jeep for what you need. Also don't forget about the programming for them I think Caleb bought a programmer for the 3.7 that does gear changes. But if not since it's a stock gear the dealership should be able to make the change on that.
cmdr jim
05-04-2012, 04:34 AM
I have the 3.7L with the 3.07 gears. I was wonderin' where I could get the gears to do a swap for the QTII gearing. I have a friend who works at an offroad jeep shop who could most likely install the gears for me. My only breaking point is price, so hopefully without having to pay for an install, it won't be too pricey.
Thanks, Ross
07JeepXK has helped a friend swap gears in there 3.07 WK. You can go 3.55 or 3.73, Yes you will have to buy the front gears from Jeep or find a used front differential or gears. The rear is a Chrysler 8.25 differential with 29 tooth spline. Those are available aftermarket. If you're going into the rear end put in some type of locker while it's open. Lastly, according to 07JeepXK, a HyperTech Speedo Calibrator or MAX Energy Programmer is needed to program in the new gear ratio.
Note: I will have available in a couple weeks a used set of 3.55 front ring and pinion gears with about 35,000 miles on them and a new set of Mopar 3.55 rear ring and pinion gears for sale, if anyone is interested, I can give you a good price on these. The Front new is $855 from a dealer and about $600 shipped from an online Mopar parts store. The rear would go for $462 or $350 shipped. I could do $300 for the set, that includes shipping.
07JeepXK
05-04-2012, 05:45 AM
07JeepXK has helped a friend swap gears in there 3.07 WK. You can go 3.55 or 3.73, Yes you will have to buy the front gears from Jeep or find a used front differential or gears. The rear is a Chrysler 8.25 differential with 29 tooth spline. Those are available aftermarket. If you're going into the rear end put in some type of locker while it's open. Lastly, according to 07JeepXK, a HyperTech Speedo Calibrator or MAX Energy Programmer is needed to program in the new gear ratio.
Note: I will have available in a couple weeks a used set of 3.55 front ring and pinion gears with about 35,000 miles on them and a new set of Mopar 3.55 rear ring and pinion gears for sale, if anyone is interested, I can give you a good price on these. The Front new is $855 from a dealer and about $600 shipped from an online Mopar parts store. The rear would go for $462 or $350 shipped. I could do $300 for the set, that includes shipping.
Like stated by cmdr jim, your best bet is to get an entire front differential from a junk yard that already has 3.73 gears installed. That makes the swap so much easier and costs a lot less. All you have to do is drop the front diff and swap in the new one. As for the rear my buddy Jay purchased 3.73 motive gear ring and pinion for a chrysler 8.25 rear end. After everything is installed, purchase the Hypertech Speedometer Calibrator and change the gear ratio from 3.07 to 3.73's and enjoy! The Hypertech Speedometer Calibrator is upgradable to the max pro so you can tune your 3.7 liter at the same time. Jays 3.7 Liter WK has been rolling around with 3.73s with ablsolutely no issues what so ever and his gas mileage has even increased. He has a 4 inch BDS lift with 33x12.5R18 Toyo Open Country MT's.
cmdr jim
05-04-2012, 06:08 AM
After my transfercase swap this will be my next change, with a ARB locker in the rear and a "modified to work manually" ELSD in the front. Picture this, a 3.7l V6 with swapped gears, a manually controlled transfercase and manually lockable on all 4 corners. Rubicon like minus the transfercase 4:1, only 2:72, and a few other items....
07JeepXK
05-04-2012, 07:07 AM
That will be one sick Jeep. Pick up a set of JBA shorty headers and tune your XK and you will be set!
cmdr jim
05-04-2012, 08:37 AM
That will be one sick Jeep. Pick up a set of JBA shorty headers and tune your XK and you will be set!
I have the JBA headers, they have been on about a year, A Fastman throttlebody, K&N cold air kit and just recently, the Hypertech Max Energy programmer. No cat back changes yet, never cared for the sound of a V6, rather be quiet.
Liking it, will like it better with the 3.73 gears! I need to add all my mods to the signature.
07JeepXK
05-04-2012, 08:56 AM
I have the JBA headers, they have been on about a year, A Fastman throttlebody, K&N cold air kit and just recently, the Hypertech Max Energy programmer. No cat back changes yet, never cared for the sound of a V6, rather be quiet.
Liking it, will like it better with the 3.73 gears! I need to add all my mods to the signature.
Sorry about that. I forgot you were the one running the JBA Headers. Sounds like you have a nice setup. Get that transfer case in there and those gears. What lift are you running or are you still stock?
cmdr jim
05-04-2012, 09:24 AM
Just the RC 2" with Rusty's leveling plates up front.
Hey look my signature showed up!
I am very interested in those 3.55's. What are the losses with going with that setup instead of 3.73's?
07JeepXK
05-05-2012, 07:50 AM
Honestly that's such a small difference that it won't be to noticeable. If you go with the 3.55 you most likely wouldnt need to buy the Hypertech programmer. Since the 3.7 liters came with 3.55 as an option the dealer should be able to program the new gear ratio....
cmdr jim
05-06-2012, 10:54 AM
I am very interested in those 3.55's. What are the losses with going with that setup instead of 3.73's?
RPMs for 3.55 will increase by 16% over 3.07 gears
RPMs for 3.73 will increase by 21% over 3.07 gears or about 5% difference between the 3.55s to 3.73s.
How much do you have invested in the 3.73's, if you don't mind me asking?
cmdr jim
05-07-2012, 04:35 AM
How much do you have invested in the 3.73's, if you don't mind me asking?
More than I should, but I'm also adding a manually controlled ELSD in the front. You can buy rear aftermarket 3.73s, it's the fronts that cost a lot if you want new, only Mopar makes them. Otherwise a used front differential out of a 4.7L with 3.73s will work, but the pinion flanges may be different.
07JeepXK
05-07-2012, 06:21 AM
Jay paid $450 for the front differential from a local junkyard out of a 4.7 Liter WK, approx. $300 for the rear Motive Gear 3.73's and $230 for the Hypertech Speedometer Calibrator. So total cost was $1,000 for the 3.07 to 3.73 swap. Labor was free since we did the install.
If I could pick up those 3.55's for 300 from cmdrjim and get the programmer for like 250, I would end up paying 550. That's not including install, but I am able to get a discount, as a member of my Jeep group is the owner of an off-road shop. I'm just not sure if I want to regear without going with the more powerful 3.73's. Or, I could just hold off and upgrade to the OME lift and an offroad winch bumper :D
07JeepXK
05-07-2012, 08:07 PM
Gears first. Then OME and bumper. Or all three...lol
My other concern is I have an extended Carmax warranty. I'm going to speak with someone at Carmax this afternoon to see how regearing would affect my warranty
07JeepXK
05-08-2012, 10:05 AM
It will probably void the warranty.
cmdr jim
05-08-2012, 04:58 PM
My other concern is I have an extended Carmax warranty. I'm going to speak with someone at Carmax this afternoon to see how regearing would affect my warranty I think 07JeepXk is correct.
Sal-XK
05-08-2012, 06:03 PM
They would have to be smart enough to figure out you re geared first LOL
07JeepXK
05-08-2012, 07:41 PM
That is true.
cmdr jim
05-09-2012, 09:26 AM
Then, they would have to prove that the re-gearing killed your engine, transmission or transfercase. But your differentials, no warranty there you broke the seal as it were.
The warranty basically says, as long as what ever needs fixin' was not affected by the aftermarket modifications,such as gearing or lifts, then it's no problem. So if my engine goes out, they will fix it no questions asked. After thinking it over, I think I'm just gunna save up for the 3.73's. I know I could get the 3.55's for a steal from cmdrjim, but I think that the 3.73's will be worth it in the long run (won't have to upgrade later on).
07JeepXK
05-10-2012, 06:33 AM
The warranty basically says, as long as what ever needs fixin' was not affected by the aftermarket modifications,such as gearing or lifts, then it's no problem. So if my engine goes out, they will fix it no questions asked. After thinking it over, I think I'm just gunna save up for the 3.73's. I know I could get the 3.55's for a steal from cmdrjim, but I think that the 3.73's will be worth it in the long run (won't have to upgrade later on).
I would really like to see cmdr jim sell those gears to help cut the cost of his 3.73's, but at the same time I think you made a great choice. If it was my Jeep it would bug the crap out of me after the install knowing I could have went with a little lower gear. Im just waiting for some 4.56's to come out for our front end.
cmdr jim
05-11-2012, 09:26 AM
The warranty basically says, as long as what ever needs fixin' was not affected by the aftermarket modifications,such as gearing or lifts, then it's no problem. So if my engine goes out, they will fix it no questions asked. After thinking it over, I think I'm just gunna save up for the 3.73's. I know I could get the 3.55's for a steal from cmdrjim, but I think that the 3.73's will be worth it in the long run (won't have to upgrade later on).
Not a problem, just offering up first dibs, if I don't sell them on a forum, they go on ebay. :)
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