Transmission Question - NAG1 Vs 545RFE - JeepForum.com
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post #1 of 10 Old 01-12-2011, 11:20 PM Thread Starter
indianajeep
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Transmission Question - NAG1 Vs 545RFE

Here's one of those issues that causes me to say, now why did they do that? Ok, the new Challengers with the HEMI engines have the NAG1 Transmission. But the WK's with the HEMI engines have the 545RFE transmission - why? Wouldn't it seem logical to have the same transmission behind the same engines in these two applications? I have not had any issues with the NAG1 in my 05WKJ or with the NAG1 in my wife's 08 Dodge Nitro RT with the 4.0L engine (there was a wiring harness problem that cooked 2 tranny control modules in the Nitro - but since they fixed that over a year ago, no issues - knock on Mopar sheet metal).



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post #2 of 10 Old 01-13-2011, 01:01 PM
Budasac
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I'm pretthy sure the SRT WK also has the Hemi and a Nag1. For some reason I believe it has to do w/ the transfer case. The 3.7 and SRT w/ the Nag1 have no 4 wheel Low option.
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post #3 of 10 Old 01-14-2011, 03:53 AM
TJ9999
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The NAG1 transmission has no Low Gear.

*** 2004 TJ Rubicon 4.7L Stroker / 42RLE / NV241 / 3" lift / 34" tires ***
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post #4 of 10 Old 01-14-2011, 07:26 AM
cmdrjim
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Quote:
Originally Posted by TJ9999 View Post
The NAG1 transmission has no Low Gear.
Actually, the 3.7L V6 QT1 AND SRT8 use single speed transfer cases. The 3.7L uses the NV140 and the SRT8 uses the NC146 transfer case. So no low gear from the transfer case.

However, if you look at the gear ratios of the NAG1 all the gears are lower then the transmission in the 4.7L & 5.7L.

Personally the fact that Jeep put this transmission behind the 6.1L V8 of the SRT8 gives me a feeling of security having it behind my 3.6L V6.
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post #5 of 10 Old 01-14-2011, 07:30 AM
meep
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i like the nag1 on my wk. it seems very picky with fluid quality. i've swapped it twice, and both times the shifts have become different. not bad, just slightly different.
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post #6 of 10 Old 01-14-2011, 07:36 AM
meep
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OEM plugs were NGK!

08 WK 3.7 2wd.

Finally did plugs last night at 31k miles. I bought champions to stick in there after all of the pretty much common knowledge that champions were oem, jeeps prefer champions (especially the v8s). So out comes NGK ZFR6F-11G.

They all came out with .045-.046 gap. stock I think is .043, depending on where you read it.

Other tidbits.
What a cute little throttle body!!! I want to say my 2.2L subaru had a bigger one! It was, for all practical reasons, clean and needed zero help in that area (I only run synthetic oils at 6,000 mile intervals).

Champion Plats went in, runs fine. No real change in performance, tho it feels a touch smoother.

The plugs came out with WAAY different amounts of tightness! Some just came out, some had to be wrenched pretty good (for plugs). Considering I had the same experience with brake bleeders on this thing (one snapped off), I think the assembly QC must be pretty pi$$-poor.

Anyway, new info. (?) NGKs are oem in the 08 3.7.

M
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post #7 of 10 Old 09-08-2016, 05:05 PM
Penguin_Jeep
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Quote:
Originally Posted by TJ9999 View Post
The NAG1 transmission has no Low Gear.
Low range is determined via the transfer case!
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post #8 of 10 Old 09-08-2016, 05:09 PM
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Quote:
Originally Posted by meep View Post
i like the nag1 on my wk. it seems very picky with fluid quality. i've swapped it twice, and both times the shifts have become different. not bad, just slightly different.
My 3.0 CRD rolled off the production line 21st June 2005, the Miles are around 112,000
My handbook says it doesnt need doing... Like the Mercedes we have owned for 15 years now (C320) on 200,000 miles is also claims to be a lifetime fill.

Both seem to run 100% - no shifting issues.

When did you change out your Jeep Tranny fluid?
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post #9 of 10 Old 09-08-2016, 05:42 PM
luckyse7ens
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Quote:
Originally Posted by Penguin_Jeep View Post
My 3.0 CRD rolled off the production line 21st June 2005, the Miles are around 112,000
My handbook says it doesnt need doing... Like the Mercedes we have owned for 15 years now (C320) on 200,000 miles is also claims to be a lifetime fill.

Both seem to run 100% - no shifting issues.

When did you change out your Jeep Tranny fluid?
"lifetime" really just means... it will last longer than the factory warranty. So they don't have to change it on their dime.

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post #10 of 10 Old 09-08-2016, 05:44 PM
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Quote:
Originally Posted by Penguin_Jeep View Post
Low range is determined via the transfer case!
Lol you dug this up from 2011!

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