2 replies to this topic

[89dogwagon]

I have a 1989 Dodge Ramcharger, 5.9L (360) TBI, V-8, 4x4, Auto trans (TF-727), NP-241 Transfer case. My transmission is terminally ill, which leaves me with various options…
1) Rebuild the existing
2) Replace with a rebuilt/remanufactured TF-727
3) Replace with a A-518 (46RH) - used, rebuilt or remanufactured
I have been reading a lot about converting to the OD transmissions but all I have been able to find is for cars with vague reference to the ability to do the same for 4x4s. I like the idea of the OD, but question the ease of this update (in the reading I have done the biggest problems are drive shaft length, transmission mount modification and modifying the body to accommodate the larger transmission) none of these is really a problem with the 4x4 except maybe if the relocation of the transfer case is required due to transmission length. The biggest problems, assuming everything bolts in without further changes (see questions) is being able to afford and find a good rebuilt/remanufactured A-518 (46RH). If I make this conversion I will control the OD and TCC as advised by PATC. I understand that I will need a 1990 through 1995 transmission to keep the hydraulic shift controls.

1) Is the torque converter the same from 5.9L (360) and 5.2L (318) in the A518 (46RH) transmissions?
2) Will the torque convertor in the A518 (46RH) bolt to the existing 1989 5.9L (360) without changing any parts?
3) Will the A518 (46RH) transmission bolt to the existing transfer case?
4) Will I have the move the transfer case back or forward due to different length in transmissions?
5) Will the existing starter bolt to the A518 (46RH) transmission?
6) Will the existing shift linkage work?
7) Will the existing throttle linkage work?
8) Will the existing speedometer connection work?
Not sure which why I am wanting to go, some will depend on the answers to these questions and the advice I get, the rest on the cost of each option.
Thanks for the answers and advice.
Jim

[TWX]

1) Is the torque converter the same from 5.9L (360) and 5.2L (318) in the A518 (46RH) transmissions?

IIRC, if it's a lockup-727, yes, the splines should be the same, but if it's a non-lockup 727, no, they're not. The lockup transmissions had one spline count different than their non-lockup units, but unfortunately I can't remember which is which. I'm fairly certain that all A518 transmissions were also lockup torque converter transmissions, but I do not know 100%.

2) Will the torque convertor in the A518 (46RH) bolt to the existing 1989 5.9L (360) without changing any parts?

I am fairly certain that the flexplates are the same. If not, since they used overdrive transmissions on the 3.9 and on other pre-EFI V8s while they also used non-overdrives, I would expect that the same number of holes are drilled in the crank.

3) Will the A518 (46RH) transmission bolt to the existing transfer case?
4) Will I have the move the transfer case back or forward due to different length in transmissions?

This one I can't answer definitively, It might be easier to simply look for a 46RH with a 4wd tailshaft and with an integrated transfer case, and to grab the front driveshaft along with, or to retrofit to a divorced transfer case. If everything is attached, my guess is that the driveshaft to the rear will be too long and to the front, too short.

5) Will the existing starter bolt to the A518 (46RH) transmission?

If it doesn't come from a Jeep Grand Cherokee it should, but it might be a good idea to pull a "mini starter" from a Magnum-era truck just in case. Should have the same bolt pattern.

6) Will the existing shift linkage work?
7) Will the existing throttle linkage work?

They both should.

8) Will the existing speedometer connection work?

I'm fairly sure that the RH model of the transmission still has the worm gear for the speedometer. A good way to find out would be to search for a replacement speedo gear for a '91 Ram 1500 or something like that.


The one thing you didn't ask about is fluid lines. You need to upgrade the diameter of the lines so that you don't overheat the transmission. You'll need bigger fittings at the transmission cooler in the radiator. It might be easier to just replace the radiator with one for a '92 or '93 Ram, as that would have the correct fittings, and the lines from that application would work too.

[dana44]

3) Will the A518 (46RH) transmission bolt to the existing transfer case?
Save the hassle and make sure you have a 4X4 transmission because of the flange, from there check the cross-reference of your transfer case to transmission.

4) Will I have the move the transfer case back or forward due to different length in transmissions?
The overdrive is about half the length of the tailshaft added to the transmission, so it will sit back about 6-8 inches. One driveline going to the rear will shorten, the one to the front will need to be lengthened, but since it is a slide yoke, that won't be as big a deal to have lengthened (smaller diameter, new tube and your ends should not be that expensive).

You may be able to find a whole trans/transfer case complete at a salvage yard to get everything you need in one fell swoop, and as far as the transmission shifting for overdrive there are simple aftermarket kits to allow it to work with a switch or button, all the other linkage should line up properly.