OverlandSteve

For the longest time, I felt like my XJ's AW4 shifted a little rough, but it never actually bothered me, I kinda just accepted it as part of Jeep ownership. Along with sorta-rough shifts, it would clunk when shifting from park to Drive or Reverse, and getting it to shift out of overdrive on a hill required me to almost floor it. Well, recently, after I discovered that my "overheating" issue was actually just a retarded temp gauge, I thought I'd check all my electrical grounds, just to make sure all my electricals were working properly. Lo and behold, I found that one of the block grounds, on the dipstick bracket, was completely caked in oil from my old leaky valve cover. Keep in mind, I wasn't thinking about my tranny at this point, I was just cleaning grounds. So, I gave that ground point a real good cleaning! And, amazingly, while I'm driving today, I notice that it feels oddly... nice... and smooth... and then I noticed that my shifts were silky smooth, and overdrive wasn't as aggressive... It was night and day difference! And the clunk is gone, too! I looked it up and I think that ground point is for the tranny electricals, which makes sense, SO, don't forget to clean your grounds, especially on the block.

steelybill

I believe that bad grounds sell a lot of un-needed parts, along with vacuum leaks from rotted hoses !
Good to hear that you have a silky transmission now !

cbs_24

What did you use to clean it with?

OverlandSteve

Thanks, yeah it was such a simple fix for what it did.

Some generic degreaser, comparable to Simple Green, it was covered in oil so I undid the nut, cleaned all surfaces, and put it back on.

Roler

Well, it's one fix for the common driveline 'clunk' that I haven't read about. Although yours seems to be related to the transmission functioning...

OverlandSteve

Yeah it is weird how it fixed the clunk, to be honest I was getting ready to get under there and grease that yoke up but I guess I don't have to.

Roler

"Not all clunks were created equal"

cruiser54

That dipstick stud ground is used for "transmission shift logic" for one thing. I'm glad to hear this.

Another place that can get corrosion is the 2 plugs for the trans and TCU.

Cruiser’s Trans Plug Refreshing


Over near the transmission dipstick tube are 2 rather large connectors. One is black and the other gray. These 2 connectors carry all the info between TPS, TCU, NSS, speed sensor, and transmission solenoids.
Unplug each one, visually inspect for corrosion or bent pins, spray them out with electrical contact cleaner and plug them back in.


Additionally, if your Jeep is an 87 to 90 Renix, it’s always a good idea to reach up under the glovebox area and unplug the connector to the TCU and spray it out along with the receptacle of the TCU. While you’re there, find the fuse right in that area for the TCU. Remove it and spray out it’s receptacle and clean any corrosion from the fuse.

Revised 9-10-2012

CCKen

Are you sure it was the ground at the oil dipstick tube mount bracket? That's G102 (see pic).

The following are grounded there: Anti-Lock Brake Controller (if installed), and Data Link Connector. The DLC will always be there.

I can't see how cleaning this grund fixed transmission issues. Twilight Zone I guess.

G102:

Crow Horse

subscribed..........

Parsnip

I'm not extremely familiar with the grounding points and what they ground, but wouldn't it stand to reason that the input and output sensors that help with the shifting process ground to the trans body, thus ground to the motor, at the dipstick tube? Just a thought

CCKen

Very good.

The transmission sensors/solenoids do ground through the transmission, through the engine, to battery ground.

The TCM itself is grounded at G101, at the coil mount bracket studs, and at the same ground for 2000/2001.

The transmission range sensor (NSS hereabouts) is grounded at G106, on the left inner fender, near the PCM.

For '98 (possibly '97) and up there are no transmission grounds at the dipstick. Only the DLC and ALBC.

Parsnip

So I get a cookie now?

CCKen

OverlandSteve

Well, this was about to get confusing but I think Parsnip cleared it up. Just to reiterate that ground was totally engulfed in oily sludge so I don't think anything that grounds there, or through there? was working. Even if it is a freak thing I'm still happy