Transmission Fluid Pump

[crquisto]

I’m pretty sure my port transmission is not pumping fluid as it should. This is a 2000 406 with 7.4 MPIs and Velvet Drive Model 30-01-005 trannies with 2.5:1 ratios. I got a warning tone while cruising at 3200 rpm the other day (about a half second beep every 2 seconds). Retarded the throttles but the warning continued. Oil pressure and engine temp were perfect on both engines. Got it to quit by turning off the port engine, but it came back on as soon as I turned the key back on and waited out the normal test beeps. The warning was similar to, but not quite the same pitch as the test beeps that come with turning on the key. After checking the engine compartment and finding nothing obvious, I headed to port with the port engine shut down. On arrival, 15 minutes later, I cranked it up to see if the problem remained and the warning was gone. Ran the engine at idle and in gear for about 10 more minutes to see if the warning would recur and it did not.

Today I decided to change tranny fluid to see if that might help. The old fluid (2 years and 70 hours run time) looked and smelled normal - not burnt. I added 1.8 quarts to the port engine and checked the level as prescribed (run at 1500 rpm for 2 minutes, shut down and check it quickly). It showed over-filled. On the starboard side, I added 1.8 quarts, ran it and checked and the quantity was low - needed another .2 quarts for a total of 2.0.

In light of the warning, no engine anomalies, and the fluid showing over-full after running, the only conclusion I can arrive at is that the pump is not working to push fluid into the cooler and other parts of the tranny.

1. Is that a logical conclusion?
2. If so, can a pump be replaced in that model Velvet Drive?
3. I didn’t see any hose crimps, but could there be blockages in the fluid system that I could clear to correct the problem?

[bud37]

Don't jump to conclusions yet.Have you checked your manual to see what the alarm was telling you..eg...trans temp etc.

[km1125]

I don't know that particular model, but many times there is a screen that can be cleaned. Mine is on the return line from the cooler, but you have to take the line off the tranny and take the fitting out to get to the screen.

Does it shift properly? If it does, then it certainly is pumping. It may not be developing enough pressure though and allowing it to slip and increase temperature. As buc37 says, check what the alarm is actually telling you.

[tomschauer]

I believe the waring "beeps" are for high engine temp, high trans temp or low oil pressure.

[crquisto]

The alarm warns of low engine oil pressure, high engine temp and high transmission temp. I have gauges for the first two, so I’ve gotta think it’s the tranny. It shifts properly and seems to pull alright but I don’t know how to check for slippage. Thanks for the suggestion on the screen. I guess that would probably be where one of the hydraulic hoses connects to the tranny?

[km1125]

Get a parts diagram for that tranny or a service manual. You can look up the parts diagram online pretty easily and look for the screen and where it is relative to the hoses.

Do you have a dedicated oil cooler for the tranny or is it shared with your engine oil? Do you have an IR temp gun? You could easily spot check temperatures on hoses and the heat exchangers if you did.

[bud37]

Source of the post The alarm warns of low engine oil pressure, high engine temp and high transmission temp. I have gauges for the first two, so I’ve gotta think it’s the tranny. It shifts properly and seems to pull alright but I don’t know how to check for slippage. Thanks for the suggestion on the screen. I guess that would probably be where one of the hydraulic hoses connects to the tranny?

Did the oil from that tranny come out clean with no dark coloured bits in it...it is the red fluid correct ?

[crquisto]

Thanks guys. Km1125, I’ve been unable to find a parts diagram on line. I’ll look again at my power train books to see if I can find one. It has a dedicated cooler and I do have an IR heat gun. I’m not sure what to look for in this case. I would expect to isolate input and output of the cooler, but don’t know if that helps identify the problem unless there is no temp drop. Guess I’ll start running comparisons with the starboard side.

Bud37, it is the red Dextron III and it was slightly discolored but no chunks and it smelled ok

[Viper]

If there was a problem with the tranny pump, you wouldn't get proper propulsion. Before you start throwing all kinds of money at this, have the ECM scanned for faults. You could be throwing a code for a faulty sensor setting forcing the ECM into default mode. Were you able to continue at high rpm with the alarm sounding?

[crquisto]

Thanks, Viper. Yes, the engine and tranny continued to run under the same rpm and continued thrust. I think these posts are teaching me a lot more about how these trannies work. I’ll get someone to read codes but still want to check heat drop across the cooler and see if I can find a filter. Still no luck finding a parts diagram of the tranny.