By Milan on Wednesday, April 11, 2001 - 06:28 am: Edit

Hi there,
I get a clunk when shifting the auto (96 disco) manually. It happens when shifting from forward to reverse or lets say when I downshift to 3rd and then once I have slowed down but am still breaking, I shift back to D.

I know that there is always slack in the whole drivetrain given all the parts but I feel it's worse then when I bought it. Or the slack may be the same but it was not really clunking before. It was just "tugging" without a clunk if you know what I mean (kind of a cushioned bang as the drivetrain tightened up).

The Disco has 33K km (20K miles). It had about 16.5K miles when I got it in November last year.

It's been a while since I had an auto and I know they clunked too, I just don't remember to what extent plus I did not care if I broke them. This vehicle I care about.

Thanks for any suggestions/opinions.

By Bill B on Wednesday, April 11, 2001 - 07:28 am: Edit

Milan - I've gotten the same since day 1 with my '97. The only thing that quites things down a bit for me are keeping the u-joints freshly lubed (every oil change) and then it is at a tolerable level. I'm sure you already do that, but figured I'd throw it out there - also have you ever changed the u-joints?

By Bill Gill (Bluegill) on Wednesday, April 11, 2001 - 07:39 am: Edit

These auto trannys are inherently "clunky" - they're built to tolerate abuse and get you home even if a bit busted up. They're not built to be silky-smooth. So says my private Disco-owner mechanic...and there obviously is a lot of slack or play in the complex system.

By Tom Proctor on Wednesday, April 11, 2001 - 08:18 am: Edit

Negative on that "clunky" auto transmission idea! The ZF is a tight unit. It should be very smooth, maybe not *silky* smooth. If it's not, you should service it! The clunkyness comes from all the links in the chain, as you pointed out Milan. More likely it is t-case slop that gets misinterpreted as trans slop.

But first, I would check the bolts that secure the u-joints to t-case/prop shaft flanges. These have been known to loosen and cause audible clunking under the conditions you describe. That would be my guess, based on your info. If these ARE loose, get new ones - they are one-use nyloc nuts.

Then check:
- u-joints for play (lube them now too)
- diffs for play
- suspension bolt (bushing) tightness
- Suspension bushing wear
- A-frame bushing(s) for play

There may be more to check. I have a 96 Disco too, about 70k miles and although I have clunking, i don't have what you describe while manually shifting the trans.

Tom Proctor
96 Disco

By pk on Wednesday, April 11, 2001 - 08:59 am: Edit

You are right about the t-case bolts Tom. It may be the ones behind the park brake drum.

By Bill Gill (Bluegill) on Wednesday, April 11, 2001 - 09:25 am: Edit

I was using "clunky" to describe when you shift into/out of gears (usually just Park-Drive-or Reverse with us auto guys). Once you're in gear and movin, there should be no clunk. Good idea to check all system bolts, though.

By Milan on Wednesday, April 11, 2001 - 01:24 pm: Edit

Thanks guys, I was going to check the u-joints just in case. So, I'm at least on the right path.
I'll report back if I either can't fix it or if it does go away.

Thanks for your time.

By Dave Thomas on Wednesday, April 11, 2001 - 03:08 pm: Edit

Didn't the earlier Discos have a problem with lube on a gear in the t-box that caused premature wear? I had heard before that this was the cause of the 'clunking' that some Discos have when going from fwd to reverse.

Anyone have any more information on that?

By donkeydon on Wednesday, April 11, 2001 - 04:07 pm: Edit

The lube gear you speak of only affects manual transmission discos and it was corrected midway thru 1997. There is some part on the tcase that should have an oil hole, but it doesnt. It has something to do with the "main-shaft spline"(im no technician) It is a design error and should have been fixed under warranty. It should not affect auto trucks.