2001 1500 4wd, 5.9 gas, 46RE transm, 175k miles

The other day, I pulled into the driveway after a short trip, went into reverse to park in the driveway (in 2wd), applied a little throttle and my rig made a "grinding" sound and the rear wheels turned some but "bucked and shuttered" would be how I'd describe the response. Drives forward fine (it seems) and goes smoothly into all gears but a little gas in reverse and I get the above response. A superficial review of the shift linkage, throttle valve cable, ATF fluid level (engine running in Neutral on level ground) and quality all look ok.

I've only owned the rig for a few months but the transmission was rebuilt (before I owned it) at about 120K - not sure what was done. I will add that I noticed in colder weather, putting the transmission into reverse gave a whining sound - which to my my understanding was "normal" (although my 94 Jeep Grand Cherokee with a 46RH has never done that).

So before I drop the trany and tcase to have a look inside (and probably end up doing a rebuild), I'm wondering if any transmission folks out there have any "gut instinct" thoughts on probable cause?

 

Might want to download the factory service manual for your year truck and take a look at the transmission section for troubleshooting your reverse issue - https://dodgeforum.com/forum/2nd-gen...e-manuals.html

 

I would disconnect the linkage and move the lever on the trans to see you still have the detents on all the gears. There is a ball bearing with a spring behind it that holds the rooster comb in position(each gear position, middle of the pic below) If the spring broke, ball popped out or the rooster comb is damaged you won't feel it go into each gear position. If that's the case the linkage could position it between park and reverse and could get what you are experiencing.

 

Yup, have the FSM and looking through it now...

 

Thx. I'll be looking first at all options before dropping the case out of the vehicle. I does shift into Reverse with no grinding or issue, only when you try to move the vehicle with some throttle does it start to grind and shutter.

A slight sidebar ... I find it interesting that the 5.9/46RH combo I have in my 94 Jeep Grand Cherokee ZJ responds very differently to the 5.9/46RE that I have in the 1500. When I put the ZJ into any gear, it wants to roll immediately (on level ground) and I need the brake to hold it in place. The 1500 on the other hand requires some throttle to get it to move when first into any gear. Is that normal for a 1500? Or does that suggest a poorly set throttle valve cable? I would have thought that when first in gear that the vehicle should want to roll... Unclear to me if this is in any way related to my current issue but I put this out there FYI.

 

Mine will roll a bit at idle, which I do believe is indeed normal. (on a flat surface....) Lotsa possible reasons for it not doing so... not all related to the trans either.

 

Sonnax has a lot of upgrades/fixes for transmission problems.

 

Yes indeed, lot's of other reasons for it not to roll at idle - brakes being one of them (which I did check and confirm has very little drag).

 

Thx. Yup familiar with those guys.

When I fully rebuilt the 46RH in my Jeep, I looked at their stuff but bought a master kit from transmissionbench.com (has a good video series on YT to rebuild a 46RE/H) and a Transgo JR shift kit. Very happy with the results.

 

OK, after taking a few weeks off, I got back at this - and made some surprising discoveries...

Here's what I did:
1. Dropped the transm pan - fluid was clean, filter looked clear and no metal parts or chips at the magnet.
2. Valve body looked good, shift mechanism moved cleanly - no obvious issues. Rear servo looked good although I did not not air test it.
3. Adjusted both bands and throttle valve linkage. All seemed close to spec before adjustment.
4. New filter and refilled ATF-4 fluid level set per FSM.
5. Drive test - same result.

Feels like drivetrain is binding when moving in reverse. Only this time I noticed that the vehicle does not want to move backwards in EITHER neutral or reverse. Shifts clean into all gears. My driveway has a grade to it and trying to roll backwards in neutral caused binding... ??????????????????????????

I then jacked up the rear axle on stands and (in 2WD), ran the vehicle in all gears - and NO binding. Reverse worked fine even with a little throttle (up to 1k rpm).

This has completely changed my take on this issue. I no longer think it is a problem with the transmission, rear axle or transfer case.

So I'm thinking it must be something in the front end. I then jacked up the front end thinking I might have a brake caliper binding but both wheels rotated forward just fine (other wheel was on the ground). I did note however that the driver side wheel would not rotate in reverse. I'm not stuck in 4WD because I would have come off the jack stands when I ran it. Not certain what to make of this.

Interesting problem and I am trying to envision a scenario that would prevent the front axle from rotating in reverse in 2WD? Thoughts?

Next, I'm thinking I will pull the front diff cover off. I did have it off and looked clear when I replaced the u-joints on both front axles a couple of months ago (and it looked good then). (Might this repair be related?)