Trans oil change

jakekooser · 03-16-2014, 04:41 AM

I changed the trans oil in my '86 yesterday, and figured I could share what I learned. Using a harbor freight suction cup to stick a funnel to your quarter window with a hose on it is a fantastic solution:

It's probably the best idea ever, until you realize the Germans had some anti-gravity technology applied to the transmission fill plug hole and it just dumps out into the drain pan you left under the car (you DID leave the pan until you were finished, right?). In retrospect, the suction cup idea might have worked with a smaller diameter hose, but the (fortunately empty) funnel fell off the window right after I took the above photo.

In the end, I went to the parts store and bought one of the pumps that screws into the quart bottle, but it wanted to leak the same amount that it actually put into the transmission, so back to another store to get a suction pump, which I suppose I had seen before but never considered, and it ended up being the best solution:

I literally had the oil back in the transmission 30 minutes after getting home with the suction gun, after spending several hours with sub-standard methods and tools.

I really did want that suction cup idea to work though....

jakekooser · 03-16-2014, 07:26 AM

Just a follow up, I changed the oil because I was not sure what was in the transmission and I have a bit of a grind when I shift from 1 > 2 under hard acceleration. I put in the Kendall 80W-90 and it seems to have improved a bit, but there is still a bit of a crunch. I have a new clutch cable, and I was going to continue on with a clutch cable adjustment first and then to replace the cable, but I don't have an assistant to help hold the pedal down to check the adjustment. I'll work on getting that done this week. I also ordered a rebuilt coupler from 'the coupler whisperer' that I will try as well.

mrehrer · 03-16-2014, 09:42 AM

Quote:

Originally Posted by jakekooser

Just a follow up, I changed the oil because I was not sure what was in the transmission and I have a bit of a grind when I shift from 1 > 2 under hard acceleration. I put in the Kendall 80W-90 and it seems to have improved a bit, but there is still a bit of a crunch.

The crunch is telling you to shift slower. There is no oil or coupler fiddling that will fix this.

jakekooser · 03-16-2014, 10:49 AM

I can live with that. Even just changing the oil made a noticeable difference, and I don't need to be shifting that aggressively anyhow.

Matt Monson · 03-16-2014, 11:26 AM

You may have seen Pete Z talk about a two stage shift on the 915. The first stage is when the slider grabs the synchro. This is the point where the slider is bringing the loose gear up/down to its speed.

Stage two is once that change in speed has occurred and you are locking the teeth of the slider onto the teeth of the dog teeth. And then the shift is complete.