Hey all, been lurking on here for a while when searching for solutions, updates and just plain good things to do to my Disco 1. However, I've run into a problem that I can't seem to find an answer for. I've taken it to a Rover shop, but at the time, we couldn't replicate the issue. I'll start by explaining the symptoms and what's happening and maybe someone has had the same issue:

1999 Disco 1
Auto Tranny
108K miles

I had started the truck after changing the oil cooler lines (they were leaking) and changing the oil. Backed it out of the garage and let it run for about 10 minutes to check for leaks. No leaks, so I got in and started home.

Going down a hill, I noticed the truck seemed to be down on power and upon reaching the bottom, I pushed the pedal down to continue my momentum, but the rpm's just went up and the truck wasn't accelerating - much like the feel of an auto transmission that is slipping because of low fluid. I coasted into a local hotel parking lot and put it in reverse - no go. Put it back in drive - no go. The truck revved and the torque was there, but wasn't going through the wheels. It almost felt like the emergency brake was on. So, I shut it down, turned the key back on and put it in neutral. The truck didn't roll. I was on a slight incline, so I was perplexed.

Called my friend who owns a Rover shop and he came with a tow strap to get me out of the way. Checked the tranny fluid, it was still looked new, if not a bit over full (I purchased the truck a few weeks ago). With a slight hesitant tug, the truck moved and we pulled it over to an empty few spaces. I started her back up, put it in drive - and voila, we were back in business. Drove it back to the shop (no issues) and my friend put it through some paces, romping on it a bit around the block and could not replicate the issue. I drove it home without a problem.

Later that evening, we were headed out of town and, on the freeway, doing about 60, I started to feel the lack of power again, and then, the rpm's just let go and went to 3K, I dropped into 3rd, no change, put it back in drive, no change - by this time, friction forces came into play and I had slowed to about 40mph - still no power. Revved it in an easy manner, just get it off the road and pulled into another parking lot. I smelled something a bit warm, like brakes or clutch - eek. Put the truck in reverse, barely moved - back in drive - no go. Again, I turned the truck off for a bit (about 5 minutes), turned the key on and put it in neutral - again, it did not roll. I got out and had my girlfriend put it in drive (engine not running), then back in neutral. I was just about to start pushing the rig, when I heard a small pop and the rig was again free to roll and did so slightly towards the angled terrain.

Started it back up and put it into 1st, voila, there we have good function again (WTF!). So, instead of putting it in drive, I just manually shifted from 1st, 2nd, 3rd, and drove home at 40mph. Had no problems the whole time.

Next day, I decided to do some tests, drove around all over using manual shifting from a stop - 1st, 2nd and 3rd - starting of in 1st at stop lights an not exceeding 40mph (because I didn't use drive). I even put it in drive a few times (where the slipping had occurred before). Never had a problem for most of the hour I was testing. However, just about home, I was in second, and again felt the familiar "slipping", no power feel. I just let off the gas and coasted right into my driveway. There she has been sitting.

There are no leaks from the transmission, just the "normal" drips from the TC. However, there is a definite, "knock" when putting it quickly from Park to Drive - and sometimes when putting it from Drive to Reverse, and back. However, if you do it slowly, there is no "knock". My friend said the front diff might be worn enough, where the teeth have "worn down" enough, that they are banging when engaged. Might be a separate problem though, as the slipping gear is making me think Transmission. Although, since it works nearly flawless while manually shifting, I keep thinking a seal or valve creating pressure loss. OR, the TC is hosed and is slipping out and creating a "neutral" affect.

I hope any of the Gurus can aid in this diagnosis or if they can give me another place to look or process to replicate and pinpoint the problem. If more information is needed, please let me now. Thanks so much all!

PS: Sorry for the length!

 

While I can't offer much help, is transfer case full? And have you considered changing it to 85W150? Have you exercised you transfer case shifter? Your "knock" is perhaps a U joint on one of the drive shafts.

 

I have not had time to check the TC for full fluid, but the small drip that I have confirmed as "normal" for these trucks, looks clean. I will check the level tomorrow and consider that 85W150 fluid.

Funny thing you mention the "exercising" of the TC. A few days before this started, I had put the TC in LOW "unlocked" and drove a bit forward and then back in Hi "unlocked" position, drove backward, etc to work it. Boy, was it tough to get back into Hi "unlocked" position, but I eventually did and then went in for the night. My friend who owns the Rover shop, that is the first thing he checked (made sure the TC was indeed in HI-unlocked) to see if maybe that was slipping out. You might have something there as these problems started just about two days after the "exercising" of the TC. Hmm.

 

Yeah, its quite possible the TC is slipping out of 4HI.
As mentioned that knock is probably play in your ujoints. A little knock when shifting P-R-D is to be expected, but excessive clunk is usually a failing ujoint.

 

On the TC shifter, I was able to slip up my boot, and work a spray tube down through the shift pattern plate into the insides and spray both PB Blaster and white lithium, which seemed to help. Of course the best is a tear down, but I don't have time for that at the moment. Look at an exploded diagram in the RAVE before you try something like this. I guess it shows when you don't use the truck off road often enough, me and thousands of other "arm chair adventurers."

 

Thanks guys - keep those ideas coming. I know I can pinpoint the issue to get this very clean D1 back in action.

My concern with it being the TC, is that when I turn the car off (after I experienced the slippage), turn the key on and put it in neutral, there seems to be some binding that won't let the truck roll. As in, maybe the TC is low on fluid or indeed needs a rebuild and is binding up until it cools down, slightly (just spit-balling here). Then, a slight "pop" (like someone took off an e-brake) and the system is back to normal.

However, the thing that I'm not clear on, is if it is slipping out of HI "unlocked", wouldn't that show in the TC lever inside the cab (as in the lever being physically out of the HI "unlocked") or the neutral buzzer going off? When I activate the TC lever and put it in neutral, I was getting the buzzer when first exercising the TC to LOW "unlocked". Although, it WAS a PITA to make sure it was back in HI "unlocked". I'm imagining the truck hadn't had the TC worked in quite a while. But, now that I'm seeing issues there, fingers are wildly pointing that way.

Are there any other tests to see that the TC as being the issue?

Obviously, the big thing is that the transmission isn't the culprit (fingers crossed).

> Are there any other tests that can discount the tranny as being the issue?

> Could the issue be electrical? - ie: loose wire or similar that causes the gear selector to see the transmission as being in neutral and thus, causing the slipping/loss of power to the wheels? Maybe the same scenario in the TC? I thought either part was not electrically operated though, so any "out of gear" issue would happen when "manually" moving either AT or TC selector. OR, heaven forbid - a transmission seal or valve body going bad (IE: losing pressure and causing the transmission to slip).

I really don't want to take things apart that aren't "broken".

Thanks guys!

 

OK, couple of questions.... When you say you've been driving in "4HI" where exactly is the lever of the transfer case? "4HI" suggests you are driving with the diff locked on dry pavement which is a bad idea and might explain a couple of things.

You should be driving with the lever the the "bottom right" location (when observed from the inside of the truck). That is the 'unlocked - HI' position.

See this thread for a clear explanation..
https://landroverforums.com/forum/di...er-case-40801/

 

Thanks for that question and clarification, WaltNYC. GAH, I totally fouled that up - I know better! Yes, you are correct regarding my mistaken vernacular of the 4HI position. I'm actually in the "bottom right" for HI - "unlocked". Totally my mistake.

So yes, all referral to the position of the TC lever above has been corrected and I never actually "worked" the TC in the "locked" positions (no light on the dash)- only the bottom right and upper right of the pattern in the TC mechanism (moving forward and backward), in each.

I do not think that this would have contributed to the issue, but again, as the above symptoms had occurred not a day after I moved that TC stick, I was prone to believe there might have been a cause to the problems. This may mean there is something more serious, I imagine.

 

Sometimes my TC is difficult to fully engage when moving among the various positions. It feels as though it is locked into position, but remains just a hair outside. I've even had it pop out of gear and into neutral when I've not set it into position fully. This results in me gliding along without power. A little extra shove into position and I'm good to go.

The TC is a just a bunch of gears so you are either in neutral or not. A slipping symptom might suggest a gearbox problem of some sort.

 

^ As much as I want it to be the TC - cheaper and easier to replace - those were my thoughts exactly. Either its in the gear or its not.

So, now to start diagnosing the transmission's inconsistent behavior and hoping its something as simple as swapping out the Valve-body or seeing if the screen filter is clogged. It might be time to drop the "newish" fluid to see if there is any "gray" matter or metal in it. I guess that would tell me if the clutch packs are hosed or worse, I need to be my friend's "shop lackey" for a while to work off a used transmission. I'm not looking forward to swapping it out with no lift. <shiver>

Any other things I should look for before tossing this transmission?