Hi All, when I drained out the diff fluid, I noticed there wasn't a whole lot in there, maybe less than half a quart. Filled it up to the proper level and when I took it out and took it once up to 90mph then back down, I pulled the rear clam and discovered it had sprayed a bunch of fluid out of the red vent. I thought this was strange since it was at the right level. I decided today to try and check to see if the pump was working. I got the car in the air, warmed it up, took the rear wheels off, got it into 4th gear and took it up to around 4,000 RPM. I took both hoses for the cooler off the pump and the top of the case and it wasn't pumping any fluid. Not sure if it needs to be going faster. Wondering if I should pull the pump and try and clean it or bench test it.
When I changed my GDU fluid (every 10 hours) I wold put the car in the air and take the return line from the top of the GDU and put it in a bottle then I would slowly rotate the rear wheels and the oil would pump through. I would keep doing this until fresh fluid came through. So you shouldn't have to run the car at speed to get it to pump. It sounds like something isn't right.
Charley
@charleyhradicalsportscarregistry-com I’m guessing the pump isn’t working. Happen to know if they are rebuildable? I couldn’t find an exploded view diagram of the pump. The quaife diagram doesn’t even show a pump, just a block off plate. Did some SR3’s not come with the pump and diff cooler?
It could also be I didn’t get the pump primed, I’ll try these instructions I just found on pistonheads:
“Priming of gear drive oil pump: I found that after refilling oil into the gear drive, the oil the pump needed to be primed to start working. The only way I managed to do this was by overfilling the gear drive to reach the level of the oil pump. I then turned the wheel to see if any oil is beeing pumped. At one stage even this would not work and I needed to use a vacuum pump to suck oil out from the line exiting the oil cooler. Once the pump is pumping I drained the excess oil to the correct level.”
Update: The issue was the pump wasn’t primed. I followed the instructions in the previous post and intentionally overfilled the GDU by about a quart and after spinning the wheel by hand about 3 revolutions oil started dripping out of the GDU pump. I then hooked back up the cooler and rotated the wheel again until fresh fluid came out of the cooler, after this I opened the inspection plug and allowed the excess fluid to drain. With the fluid at the right level and inspection plug replaced, I then rotated the wheel again and verified the pump was still primed. All seems well now.
Great news! I am glad to hear it was an easy fix.
Charley
I’m not sure if the following solution makes sense as I can’t say I know precisely how the oil pump works, but given there are a few threads on this gdu oil pump priming issue I thought I’d add as it should save us some oil.
Had a similar issue with oil not flowing out the top return line after fully draining. Loaded up gdu with a second quart of oil, started engine and let the car run in 1st gear for a minute (already up on jack stands). Nothing.
Put engine back to neutral and shut it down, then tried filling the oil down the return line. The key is filling a little at a time as to not make a mess, but rotate your discs in *Reverse* while doing it so it sucks the oil down into the cooler through the return line. If you don’t rotate in reverse all you’ll do is decorate the top of your gdu with oil…
I wouldn’t fill the whole gdu this way, just a few dozen mL to fill the cooler and return line down to the pump.
Checked oil level a few times while doing this and it kept draining, so new oil was being added. I then replaced the oil plug and the return line to seal up the gdu, rotated the discs *forward* quite a few times. Then disconnected the return line and rotated the discs *forward* some more to see if it worked. Oil came out, pump was primed.
