Swapping AT for 6-speed manual: pros vs cons?

Gypsy62 · **Posted:** Sun Nov 13, 2016 5:43 pm

I'm still swapping stuff between my '05 gasser and CRD.
Upon completion, I'll post a how-to with pics on complete front and rear end R&R.

Although I hadn't planned to swap tranny's, I'm still interested in hearing arguments for and against. Given that I own both complete running vehicles, here and now would be the place and time if I'm gonna' do it.

AT or stick, I'm selling the RV-toad-rigged gasser on the RV boards. Maybe it would be more valuable to THAT crowd converted to an AT.

Also, next year I may be returning abroad permanently. IF so, I'll likely sell my CRD on LJ: ARB lockers front/rear, ARB front bumper, 2.5" Franken lift, NEW: HG/Exhaust valves, all seals (head&intake hot-tanked, head decked, seats spun)/ARPs/Tbelt kit/Sasq 1&2/Etecno glos/motor mounts/Samcos/Kennedy pump/later fuel-head/ fan clutch with 11-blade/duratracs. By next summer, likely exhaust mods, more... So, would converting the CRD to a 6-speed add that much more 'frosting to the cake' among LJs?

The ECM/TCM would have to be swapped: what nightmares would that trigger? Non-conforming digital VIN data?

Thanks.

tjkj2002 · **Posted:** Sun Nov 13, 2016 9:37 pm

Huge con is the manual is not rated to handle the CRD without first having to be de-tuned.

Resale value may go up only to those in the section but in the real world would be worthless since parts would be next to impossible for the average person to get and a no-go for any shop including a dealership.

mass-hole · **Posted:** Tue Nov 15, 2016 7:36 pm

Well for one, the automatic transmission tuning on these seems to be pretty limited in its logic and it sucks, meaning the transmission shifts at x speed and if you dont like it too bad and you have to floor it to get it to downshift, so someone who likes more control over gear selection may really appreciate the 6 speed. I know i would for daily driver duty here in the mountains.

I would imagine it would not be as good for towing. I also dont think that the gearing is as tall as the 5 speed auto so 6th would be pretty revvy at highway speeds with out regearing the diffs. Speed limits are 80mph around here so my jeep would be spinning away at like 3000 rpms on the highway.

Gypsy62 · **Posted:** Sat Nov 19, 2016 11:42 pm

Thanks for the replies.

And to tjkj2002... 12,659 posts dating back to '06? Seriously?
Holy smokes; You must be "The Original Vampire" in LJsylvania!

I may only be a newbster on this CRD board, but Thank You for your service!

carbcoma · **Joined:** Sat Oct 01, 2016 9:48 pm **Posts:** 86

Hi I see on rock auto an option for a manual transmission for a 2006 liberty crd. Can this be installed on these jeeps?

Gypsy62 · **Posted:** Wed Nov 23, 2016 2:45 am

Re your rock auto question, the 6-speed manual was an option on the Gasser, but not the CRD. However, the manual tranny's bell housing will bolt to the CRD's 2.8, and it's also compatible with the rest of the driveline geometry.

If the idea has you drooling, remember to consider how many parts are involved as well as the extensive labor:
Pedal swap.
Console swap.
Instrument cluster swap.
ECM/TCM swap.

And I'm probably forgetting a bunch of additional stuff.

I can't justify the insane amount of associated labor.
I prefer sticks, but not THAT much.
But it's still interesting hearing from folks regarding pros and cons of a swap.

lacabrera · **Posted:** Wed Nov 23, 2016 8:47 am

I have had the pleasure to own and drive both versions 2004 2.8CRD auto and my 2005 2.8 CRD 6 speed. I would say I much prefer the manual over the auto. Yes the manual max torque is rated at less than the standard torque available from the motor but having towed with it for the last 2 years, with a 2 metric ton trailer with a version of a hot tune the transmission has stood up to the abuse. I feel the rating for the 6 speed is very much on the conservative side. The only issue is the DMF and clutch plate are a known weak point. RPM at speed is not an issue as the car rarely sees speeds above 60MPH. With the equivalent of 30" tires and my standard gearing + or - 2100 RPM. Also I would add the transmission is probably the only part of this car I have not had to repair?? German engineering.

Gypsy62 · **Posted:** Wed Nov 23, 2016 1:14 pm

I see that you're in the UK: so it was only North America where a CRD stick was unavailable, everywhere else it was an option?

And interesting and valuable real-world 6-speed towing insights.

mass-hole · **Posted:** Wed Nov 23, 2016 2:42 pm

lacabrera wrote:

I have had the pleasure to own and drive both versions 2004 2.8CRD auto and my 2005 2.8 CRD 6 speed. I would say I much prefer the manual over the auto. Yes the manual max torque is rated at less than the standard torque available from the motor but having towed with it for the last 2 years, with a 2 metric ton trailer with a version of a hot tune the transmission has stood up to the abuse. I feel the rating for the 6 speed is very much on the conservative side. The only issue is the DMF and clutch plate are a known weak point. RPM at speed is not an issue as the car rarely sees speeds above 60MPH. With the equivalent of 30" tires and my standard gearing + or - 2100 RPM. Also I would add the transmission is probably the only part of this car I have not had to repair?? German engineering.

That is what I was talking about, you are already at 2100 rpm at 60mph. If you were going 75-80mph, 30% faster, like most people like to do here you would be at 3000 rpm. That would suck.

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lacabrera · **Posted:** Wed Nov 23, 2016 5:22 pm

mass-hole wrote:

lacabrera wrote:

I have had the pleasure to own and drive both versions 2004 2.8CRD auto and my 2005 2.8 CRD 6 speed. I would say I much prefer the manual over the auto. Yes the manual max torque is rated at less than the standard torque available from the motor but having towed with it for the last 2 years, with a 2 metric ton trailer with a version of a hot tune the transmission has stood up to the abuse. I feel the rating for the 6 speed is very much on the conservative side. The only issue is the DMF and clutch plate are a known weak point. RPM at speed is not an issue as the car rarely sees speeds above 60MPH. With the equivalent of 30" tires and my standard gearing + or - 2100 RPM. Also I would add the transmission is probably the only part of this car I have not had to repair?? German engineering.

That is what I was talking about, you are already at 2100 rpm at 60mph. If you were going 75-80mph, 30% faster, like most people like to do here you would be at 3000 rpm. That would suck.

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But I bet you can not drive your auto at 30MPH or even 40mph at 1000RPM up hill :ROTFL:

like I said I drive both reving at 2000rpm all the time on a diesel very uneconomical.

mass-hole · **Posted:** Wed Nov 23, 2016 7:26 pm

lacabrera wrote:

mass-hole wrote:

lacabrera wrote:

I have had the pleasure to own and drive both versions 2004 2.8CRD auto and my 2005 2.8 CRD 6 speed. I would say I much prefer the manual over the auto. Yes the manual max torque is rated at less than the standard torque available from the motor but having towed with it for the last 2 years, with a 2 metric ton trailer with a version of a hot tune the transmission has stood up to the abuse. I feel the rating for the 6 speed is very much on the conservative side. The only issue is the DMF and clutch plate are a known weak point. RPM at speed is not an issue as the car rarely sees speeds above 60MPH. With the equivalent of 30" tires and my standard gearing + or - 2100 RPM. Also I would add the transmission is probably the only part of this car I have not had to repair?? German engineering.

That is what I was talking about, you are already at 2100 rpm at 60mph. If you were going 75-80mph, 30% faster, like most people like to do here you would be at 3000 rpm. That would suck.

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But I bet you can not drive your auto at 30MPH or even 40mph at 1000RPM up hill :ROTFL:

like I said I drive both reving at 2000rpm all the time on a diesel very uneconomical.

I rarely ever drive that slow. Any roads here are 55mph+ except in town so I am either locked in 4th, or if I want I hit 59mph and lock 5th and then slow back down to 55. The 10 minutes I spend in town is around 35mph with one road that is 55.

I would never be able to maintain 1000 rpms on the hills around here anyways. The torque on these motors drops off pretty significantly below 1800 rpm by design(the tune), anything below ~1600 rpms and the motor is not happy.

I dont dislike manuals, up until this jeep thats all i've owned, but I think its kind of a tradeoff with the 6 speed that came in this jeep. If it used a T56 like I had in my Pontiac GTO, it would not be an issue since 6th gear would have been a .56:1. That car could chug along at like 75 mph and still be below 2000 rpm. This motor could really take advantage of a wider ratio spread due to the torque.

lacabrera · **Posted:** Thu Nov 24, 2016 5:57 am

All depends on the road conditions, here in the southwest UK majority of the roads are country lanes and you can rarely go above 50mph. Having a higher gearing would make no difference to me but if your journeys involve higher speeds than yes the reduced RPM would make a difference. My 2004 auto would do 37MPG UK gallon on a 500 mile trip to Spain but under normal day to day driving lucky to get 22MPG but my manual will do nearly 30MPG,35MPG on a long journey and that's with a suspension lift and 255 tires. Yes 1000RPM is a struggle but pulls plenty at 1200RPM, plus you get much better engine braking with a manual. Just pointing out the differences I experience between the two transmissions, not knocking either of them.
Plus its so annoying to get the auto to shift to 5th. On a half decent road here, speeds are between 50 and 60 MPH it changes gear more often than most people blink.

Gypsy62 · **Posted:** Sat Nov 26, 2016 5:30 pm

In addition to the discussion of the dis/advantages of the AT vs Manual for towing, unburdened highway driving is also a relevant consideration.
For the record, the best fuel economy I've achieved in my stock un-flashed (AT) CRD has been 24.5mpgs/10.5kpl while cruising at 95mph/152kph, turning 2950rpms. With stock tune, the VM absolutely purrs at that speed. Imo that is one of the most redeeming qualities of the CRD: among true transfer-cased 4x4's, point A to point B quickly and relatively efficiently. Essentially, utilizing its asset of torque to hurl itself down the highway rather than hauling or crawling.

Its been pointed out that thanks to the ARB & lift swap I can kiss those mpg numbers good-bye. That also raises the question of how coupling those mods with an AT-Manual swap would impact highway-driving speed and efficiency, granting lift-induced safety considerations.

Any trans-swap aside, after completing all of these major elective mechanical surgeries, hopefully choosing a flash will improve overall efficiency and performance,

mass-hole · **Posted:** Sat Nov 26, 2016 6:44 pm

Gypsy62 wrote:

In addition to the discussion of the dis/advantages of the AT vs Manual for towing, unburdened highway driving is also a relevant consideration.
For the record, the best fuel economy I've achieved in my stock un-flashed (AT) CRD has been 24.5mpgs/10.5kpl while cruising at 95mph/152kph, turning 2950rpms. With stock tune, the VM absolutely purrs at that speed. Imo that is one of the most redeeming qualities of the CRD: among true transfer-cased 4x4's, point A to point B quickly and relatively efficiently. Essentially, utilizing its asset of torque to hurl itself down the highway rather than hauling or crawling.

Its been pointed out that thanks to the ARB & lift swap I can kiss those mpg numbers good-bye. That also raises the question of how coupling those mods with an AT-Manual swap would impact highway-driving speed and efficiency, granting lift-induced safety considerations.

Any trans-swap aside, after completing all of these major elective mechanical surgeries, hopefully choosing a flash will improve overall efficiency and performance,

It certainly will improve. My jeep was stock other than maybe some cac hoses when I got the gde tune and I went from 25-26 avg/28-29 hwy to 28-29 avg/33-34 hwy.

However, like you I went to a lift, arb, and 265/70's and I really never see above 26 mpg now. It's pretty consistent though that I get the same mileage whether I am on the highway or just cruising around town. Driving 5 hrs to Vegas I only got 25 I believe.

I think the fact that the arb exposes the whole front profile of the tire hurts bad at highway speeds which is why I don't see any difference.

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Gypsy62 · **Posted:** Sun Nov 27, 2016 2:29 am

Here's yet another novel method to enhance fuel efficiency:
If you own a canoe, try sticking it out the rear window of your crd, facing downward. On a trip in a f350-crew (wvo'd 6.9), I stuffed a 14' fiberglass coleman into the truck's shell with a bit over 5' protruding out its' back window. I noticed that I seemed to be doing better than the usual 16.5mpg, so I began closely monitoring fuel consumption; the 5' of aerodynamic canoe-butt added a confirmed 3mpg's!

I see no reason why a CRD wouldn't yield a similar benefit, but intruding exhaust fumes could rain on that parade. Beware, or at least be weary.

lacabrera · **Posted:** Mon Nov 28, 2016 3:10 pm

Gypsy62 wrote:

Here's yet another novel method to enhance fuel efficiency:
If you own a canoe, try sticking it out the rear window of your crd, facing downward. On a trip in a f350-crew (wvo'd 6.9), I stuffed a 14' fiberglass coleman into the truck's shell with a bit over 5' protruding out its' back window. I noticed that I seemed to be doing better than the usual 16.5mpg, so I began closely monitoring fuel consumption; the 5' of aerodynamic canoe-butt added a confirmed 3mpg's!

I see no reason why a CRD wouldn't yield a similar benefit, but intruding exhaust fumes could rain on that parade. Beware, or at least be weary.

lol, I have to stick my kayak out of the tail gate rather than on the roof next time. If you looking for the best fuel economy driving at 95mph is not the answer. My recorded 37mpg was driving with cruise at 65mph pushing it up to 70+mph soon made that figure drop.

tjkj2002 · **Posted:** Mon Nov 28, 2016 8:30 pm

lacabrera wrote:

Gypsy62 wrote:

Here's yet another novel method to enhance fuel efficiency:
If you own a canoe, try sticking it out the rear window of your crd, facing downward. On a trip in a f350-crew (wvo'd 6.9), I stuffed a 14' fiberglass coleman into the truck's shell with a bit over 5' protruding out its' back window. I noticed that I seemed to be doing better than the usual 16.5mpg, so I began closely monitoring fuel consumption; the 5' of aerodynamic canoe-butt added a confirmed 3mpg's!

I see no reason why a CRD wouldn't yield a similar benefit, but intruding exhaust fumes could rain on that parade. Beware, or at least be weary.

lol, I have to stick my kayak out of the tail gate rather than on the roof next time. If you looking for the best fuel economy driving at 95mph is not the answer. My recorded 37mpg was driving with cruise at 65mph pushing it up to 70+mph soon made that figure drop.

That is a huge issue with diesels,your limited on the speed in which you get good mpg's.

I get my best mpg's hovering around 2900-3000rpm's.Could get 22mpg's before the SFA swap and that was lifted,32" tires,and weighing 5500lbs and that was cruising at 78mph and now SFA's and tipping the scales north of 6200lbs with 35" tires I can still get 18mpg's at 65mph(same rpm's as 78mph pre-SFA,I geared pretty low).

Gypsy62 · **Posted:** Wed Nov 30, 2016 12:12 pm

I assure you that running at 95mph turning 2950rpms in Stock CRD yielded the best highway mpg. 1,000's of miles, daytime driving on divided western highways, $70 iradar copilot. I watch the road. But setting aside speed, the jeep just feels right at that speed. Not 85, not 105; 95. Straight, solid, purrs like a kitten. The fact that speed is five shy of most states "Reckless" is a bonus. That speed may sound irresponsible to some, but when you've got 700 miles of desert straightaways to conquer, sometimes a shorter day is a safer day; 7.5 vs 9.5 hours.
It's worth noting that 24.5mpg figure also reflects somewhat frequent decels/resumes from 95 to 75 to 95; I suspect holding steady at 95 would improve that figure. A more uppity sniffer would scream fewer fake alerts, but it's never missed the real deal; paid for itself in the first hour.

Post-swap, I'm very curious to see how stable and safe the lifted CRD will feel on the highway. In the lifted gasser, I did have to make a race-grade 90mph swerve on I-15 when a dually changed their mind about exiting and suddenly flipped back onto the hwy. Must say it tracked like a cat. However, given that the uca/lca bolts were frozen, I expect that elevated rigidity/stability will be absent with the same Frankenlift/JBA uca's setup swapped into the CRD.
Related, I'm also curious to research how flash options alter highway economy. They must have a "target range" for programming optimized efficiency, no? If so, I highly doubt that accounts for 95mph cruising.

I just wrapped the ARB/Lift swap. Thanks to frozen lca/uca bolts, lacking my compressor&air tools, and CRD-specific r&r sequence learning curve, 100 hours of pure crap labor (grrr). A younger human's work. At least the weather's been great. Seems weird to me that those bolts could be sooo rusted but the rest of the vehicle's overall rust isn't. Thanks to rusted nips, I also had to replace both front calipers, so now virtually all of the gasser's rusty running gear has been replaced by the CRDs younger, cleaner gear. Frankly, if I'd known this swap was gonna' be such a pita I woulda' kept the off-road capable gasser and sold the CRD. At least now I can get back to wrapping the VM upgrades.

Re swap, I'll start a new thread with pics, R&R do's&dont's and sequence/procedure tips. Maybe knock someone else's oxidized grief down to fifty hours...

tjkj2002 · **Posted:** Wed Nov 30, 2016 11:50 pm

As long as you went with the OME CRD specific front coils and run some load range D/E tires with 38-42psi it should ride better and corner better then stock.

I know my gasser KJ did with 425lbs rated front coils and load range D tires at 38psi.

Now SFA'd,that is 9.5" of lift,it's of course not as stable as before(no swaybars,only a AntiRock in the front) but I can still corner better than my Town Car since it's also 12" wider than stock.

Swapping AT for 6-speed manual: pros vs cons?

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