Auto transmission shifting question

[Elemental]

Originally Posted by Disco Mike

Was this a recall or just a service bulletin?
Looks like a TSB.
Mike

A tsb. No recall, but anyone with 2 15 mm Wrenches can adjust this. It will make a HUGE difference.

[tgmiller77]

Good point. I will give Lucas a shot.

[tgmiller77]

I tried adjusting the cable. All it did was change the shift point. It still did the in and out of gear thing. I was praying that cable adjustment was all it was. Transmission shops scare the hell out of me, because it is never an easy fix always big money. I was hoping that the Land Rover brain trust could come through with an easy fix.

[Elemental]

What fluid did you use?

[bd1308]

Myabe the filter needs to be changed?

[tgmiller77]

About 300 miles ago I changed the filter and just replaced the fluid that came out with a fluid and filter change with Mobil 1 ATF. I know that was a gamble going with synthetic but Mobil 1 is not like Amsoil. With the new ATF in the market I thought why not spend the extra $1 per quart and go with the fluid that I know is good. About 5.5 quarts came out and it already looks a little dirty but I am going to drain the pan again add Lucas Transmission Additive and top up again.
If this sounds crazy let me know. It shifts great and smooth it just can't decide what gear it wants between 30-35mph while coasting.
Greg

[Elemental]

Nothing changes shift quality more then fluid. In fact, Ford has a similar concern with their transmissions. There fix is to flush out all the Dex 3 and replace with Dex 5.

Read this, learn it, Live it.

Different ATF's (Automatic Transmission Fluid) can have different frictional properties which can produce different shift characteristics. You may have already experienced problems like lock-up shudder, or squawks on shifts and have corrected them by changing the fluid. This alone tells, you that friction material and fluids are critical in today's cars.

MEETING THE O.E.M. SPECIFICATIONS

The first thing to consider when choosing an ATF is "Does it meet the O.E.M. specification?" ATF's wishing to be labeled as DEXRON II and/or MERCON must first meet the respective minimum requirements. It's important to note that even though the specification for DEXRON II and MERCON are currently very similar, THEY ARE NOT IDENTICAL. Also note, even fluids which meet the same specification may not be identical. One fluid may just meet a specification and, another may far surpass it. You should know what your fluids properties are! You can get that information from your fluid supplier.

EVALUATING YOUR FLUID

Ask your supplier to prove (certify) that the fluid meets O.E.M. specifications (MERCON OR DEXRON II). He will do that by supplying you with the license (certification) number issued to him by the O.E.M.




A DEXRON-II license number (sometimes referred to as a "D" number) will always start D-2.



MERCON license numbers will be six digits starting with M

TRY TO MEET SEVERAL SPECIFICATIONS!

DEXRON II and MERCON have different minimum specifications, so a product that meets BOTH specifications may be better then those meeting only one spec. Meeting other specs, in addition to the first two can be an added benefit. If a fluid is licensed as DEXRON II AND MERCON as well as others like Allison C-4, or Caterpillar TO-2/TO-4, it means the fluid had to pass more tests and may be a better fluid.

Lastly, demand that the license numbers be placed on all your invoices especially if you buy in bulk. If your supplier is unwilling, it is very likely that they are supplying you an unlicensed fluid. Licensed suppliers are required to supply the license numbers to their customers as part of their agreement with the O.E.M.

OTHER THINGS TO CHECK

So now you've narrowed your choices down to a few suppliers that have O.E.M. license numbers. How do you compare two fluids that meet the same O.E.M. Spec.? Ask your supplier to give you the viscometrics on the fluid you buy.

An excellent "bench mark of the overall quality of a fluid is its viscosity at -40 degrees. This is measured in "centipoise" or "cPs". DEXRON II specification says viscosity will be no more then 50,000 cPs @ - 40 degrees. (Some poor fluids have tested at over 1,000,000 cPs) In general, the lower the number, the better the fluid.

Keep in mind that as the number goes down the price of the fluid usually goes up. (You get what you pay for) Most good fluids will average around 35,000 cPs. Hydrotreated (or Hydrocracked) fluids average around 20,000 cPs or less. (Hydrotreating is a refining process done to the base oil to clean out contaminants or impurities) Synthetic ATF's average 10,000 cPs or less, and some are as low as 5000 cPs. Viscosity at -40 degrees is a function of the base stock from which the ATF is made. A low number indicates a premium base oil OR an expensive refining process. (Hydrotreating)

[tgmiller77]

Mobil 1 has got to meet or exceed the Dextron III requirements. Hell, I would have loved to been able to find Havoline or Superflow Dex III but you can't find it anymore unless you go to a gas station and look for the old dusty bottles. Everything now is "multi vehicle", but it probably is Dex III. Castrol is almost as expensive as Mobil 1 and I don't think it is as good or you can go with the private label stuff but you have no idea what it is.
I did drain the pan and add Lucas Transmission Additive and topped up the fluid with ATF. Shifting is much smoother the clunks are better and the back and forth shifting has not completely gone away but it will do it once or twice and then stay in gear. I don't know if Lucas helps torque converters or not but it does help smooth out high mileage tired transmissions.
Your help is greatly appreciated in helping me solve this issue.
Greg

[tgmiller77]

Just to give an update. It only acts up with the A/C on. If I have the a/c off no wierd shifting. I have some ignition wires on order the ones that are in there now are shot (Lucas)they have at least 80-100k miles on them which is causing some hard starting and a random miss. Will update when installed.
Greg
1997 Discovery SD7

[Adam in NYC USA]

Do a flush and a afternoon urban run (about 60 miles round trip) let go thru all the shift changes (mixed street, highway and low gear) , take it back home, turn it off and let it cool down, start her up again and then change the fluid again.

Maybe that will get anything out of the tranny baffles and you can see if it is a dirt issue or just you are getting fickle with the tranny.

The shift I hate the most are the shift past 50 mph with the rpm change and then when you start slow and then you slow down and it bucks like a bronco. In stop and go traffic, I just leave it in 3rd gear.

BTW, I have a 96 D1 with 141k. Got it at 99k.

[tgmiller77]

Alright, I changed the plug wires which cleared up several issues and it runs like a different truck. But still shifts like it did before.
Doing more and more research on this and other forums it does sound like the TSB that Badger1 sent in an earlier post. If anyone has had that problem chime in if what I am experiencing is what your truck is doing.
I just don't think there is anything wrong with my transmission. With a little more experience driving my Discovery it only: 1) does it slowing down coasting, 2)with the a/c on, 3)at about 1,200-1,500rpm, rpms jump about 400 rpm, 4) at speeds of 40-33mph. Maybe I have answered my own question, I don't know. I am a DIYer and hate to throw parts at cars searching for answers.
What is the PROM? Is it the Gems ECU? How do you tell if it is the updated version? If you bought a used one do you just plug it up and let it idle to reprogram itself?
Greg