[tdcva]

My project is a 2004 Disco SE. It was hit in the rear and front. 80,000 miles, otherwise looks good. The body repairs have been completed but of course wiring problems with a pre 2003 2004 bumper and different lights, rewiring the front end for an off road bumper, little things....

Big worry - transmission. Car drives but shifting is a little spastic.

Plan, replace tranny filter and as much fluid a possible.

So many choices on how to do, but none replaces all the fluid, and since the disco has no dipstick, checking the level and topping off is a pain, but the least of the problems. So I've studied the problem by researching on line, and come up with what I believe is a method to replace a great deal more of the fluid than other methods I've seen described.

1. Open and drain the cooling lines at the atf cooler. Low level 15-20 psi compressed air to flush out cooler. (No chemicals) Run a bit of New Dextron3 through cooler in each direction. Plug cooler fittings with suitable plug to keep clean.

2. After opening fill plug on tranny and drain plug to drain tranny, use suction gun to pull fluid through cooling lines from tranny. Remove sump.

3. The transmission has a 1" pick up tube that descends into the sump. Attach a suitable hose to this pickup, (washing machine drain hose?) and rig to an outside 5 gallon paint can through a bottom fitting added to the bottom of the 5 gallon can. Keeping the bottom of the 5 gallon can above the normal sump height will keep the pick up tube and pump supplied with oil with no (suction lift) problems.
* Put the cooler outlet line from the transmission in a drain catch can.
*Put a large garbage bag around the open sump of the transmission to create a boot to catch and direct the fluid that will be pumped out. Direct this boot to a large drain pan.

4. Add three gallons of fresh dexron3 to the external reservior.

5. Start engine and operate gearshift through all positions. Observe fluid color at discharge points. When supply ATF runs down to bottom of can, stop flush.

6. Clear coolant lines again if changing to a syn fluid.

7. Clean up mess and reattach coolant lines, attach new filter and replace gasket and sump cover and drain plug.

8. Proceed as you would normally to top off transmission with proper fluid quantity. Plan on checking fluid level at least once more after 30 minutes of driving.

9. Be observant of the fact that the transmission shift computer will be "adjusting" for changes in pressure (new filter and fluid viscosity) and new friction quality of replacement fluid.

Okay so that's the plan. And that's how I understand the transmission and how it works. I do not know how much of the Torque converter fluid will be replaced. I know some of it will be displaced by new fluid. Enough to justify the extra effort and cost of the flush fluid? Don't know. I'm planning to refill with Mobil1 ATF syn and at about $10.00 a quart, I'm willing to try to get as much old fluid out as possible.

Well that's the plan, and I've posted it here for comments. I already know I'm crazy, so please keep the comments to mechanical feasability, trouble spots, what I haven't thought of. -- Yes I'll have helpers to watch the oil levels and won't let the tranny "run dry". Yes kitty litter is available in 20 pound bags. I have started cleaning and soaking wd40 into the coolant line couplers.

Okay, the parts are on order, and I'm rarin' to go! If you see me making a misteak with my proposed methodology please let me know.

Thanks,

TDCVA

 

[Keanan]

This is a dumb idea. You are going to make a huge mess and waste a lot of fluid.

I like the ingenuity though.

If you really are going to do this why disconnect the cooler lines? Keep them connected, pull the sump, attach your hose to the pickup tube and route it to your clean fluid.

Put your drain pan under the exposed sump to catch the fluid.

By doing this you created a remote sump essentially. It'll flush out the TC and cooler. Still following me?

Let me back up, this might not be a really dumb idea. In theory it's great, in reality it's a dumb idea, only because it will make a huge mess.

What is the flow rate of the trans fluid pump? Will 3 gallons even be enough fluid?

Can I suggest a cleaner way to flush the trans?

Buy a filter kit and a gallon of ATF. Replace the filter, top off the fluid then drive around. If it shifts smoothly then you are golden, and clean and you didn't just spend a bunch of money on ATF that you spilled all over the place.

If you really want to get more fluid out then just do a basic drain & fill. Repeat two or three more times if you have too.

If it still shifts funny after one or two drain & fills you have bigger problems.







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[Disco Mike]

First, don't switch to a synthetic fluid at your mileage, just do 2 drain and refills using a bottle of Lucas tranny additive.
Seriously, what you are describing is such a waste if time. Your tranny will be just fine if you change the fluid every 15,000 miles

 

[disco biscuit]

I think its a bad idea because all you have to do is disconnect both lines to the cooler, run the return from the cooler to tranny in the new bucket of fluid, then the tranny to cooler line in a empty bucket...start the motor and let the tranny pump swap the fluid out for you. That's how most lube shops so it anyhow...why all the weird confusing **** with the sump??? Curious why the pan drop to flush. Maybe for the filter.