727 for a 4BT

[NOberdier]

Well I have been working out the particulars for my 4Bt conversion into a Jeep Grand Wagoneer. This is going to be my wifes daily driver not a rock crawler or tow vehicle so I am mainly interested in reliability and MPG. I originally going to go with a 47RH but due to the complications of controling the lock up and getting the transmission to mount up to the stock NP229 made me rethink it. The GW originaly came with the AMC version of the 727 so the diesel 727 should bolt right up to the NP229. Worse case I might have to use the AMC tailshaft and rear housing. My question is how different is the Diesel 727 from the standard gas version?? What all am I going to need to bolt a 727 up to a 4BT?? Starter? Flex Plate? Adapter? Thanks.

 

[dpuckett]

One thing to keep in mind is that the 4BT has a similar RPM range as the 6BT- higher gears are better. I wouldnt want a 3apeed auto with any higher than about 3. 40 gearing; 3. 54 at the absolute lowest. Have you considered a 518 auto? I know, no lockup, but you will have OD, which will help your RPMs and cruise MPGs.



Daniel

 

[NOberdier]

Well I had planned on using the stock 2. 7 gears which would put the engine rpms at 1814 at 60 mph. I wouldnt want to tow with those gears but it should be alright for a grocery getter. Right?? Or would that put me too low of RPMS in 1st gear??

 

[BSMiller]

I have a 90 1 ton and run between 2000 to 2050 RPM at 60 MPH with a 3. 07 rear end. It's fine for around town,but the engine is buzzing above 60 MPH. You should be fine with a 2. 7 rear end.

 

[cerberusiam]

My question is how different is the Diesel 727 from the standard gas version?? What all am I going to need to bolt a 727 up to a 4BT?? Starter? Flex Plate? Adapter?

Completely different. IIRC, you will need the the diesel version of the transmission, which can be very hard to find. IMO, you will a lot more luck finding the 47RH unit.



The t-case could be an issue. If the bolt pattern is the same the 46RH OD should bolt to it but that is an unknown.



You can put the 46RH OD unit on the 47R? units so if mixing and matching will work you should be able to make it work.

 

[TBurow]

i have a fresh 727, adapter, tc, flywheel, and starter. cheap/trade? from an 89 5. 9ctd, all working, pulled when i changed over to a 47re. pm me if interested, just in my way.

 

[TBurow]

forgot to mention 4x4 trans, also have t-case from 86 gasser w/360/auto

 

[Steve Graham]

Well I had planned on using the stock 2. 7 gears which would put the engine rpms at 1814 at 60 mph. I wouldnt want to tow with those gears but it should be alright for a grocery getter. Right?? Or would that put me too low of RPMS in 1st gear??

NOberdier,

You might want to recheck those gear ratio's. I don't find any listing for a 2. 7 gear ratio in any axles made today. Could it be your thinking of 3. 07?



Steve

 

[boatpuller]

NOberdier,

You might want to recheck those gear ratio's. I don't find any listing for a 2. 7 gear ratio in any axles made today. Could it be your thinking of 3. 07?



Steve

If I'm reading his post correctly the 2. 7 gears are in the Grand Wagoneer, so you won't find them in any current Dodge Trucks.

 

[NOberdier]

yes the 2. 7 gears are in the 88 Grand Wagoneer.