Now that the modulator holds vacuum, it will, hopefully, regulate the speed of the shifts to prevent the very hard shifts that you currently have.

But, to do that, the VCV needs to be properly supplied with vacuum. Furthermore, you'll need a suitable restriction orifice in the line to the VCV..........otherwise it cannot function properly.

You can test the function of the VCV itself by connecting the Mityvac to the supply side of the T above the VCV. The opposite side goes to the transmission and the bull goes to the VCV via the green dashpot.

Pump up the Mityvac (engine not running) and see what you get on the gauge. Then, slowly open the rack and watch the gauge. It should gradually fall toward zero. If it does this, the VCV is working properly and you simply need to route proper vacuum (with the suitable orifice) to the VCV.

The VCV held at about 10 for a few seconds and then started to slowly drop. I then began to open the rack and it dropped more rapidly. Does this mean that my VCV is bad? I did the test four or five times with the same results.

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84-300D 256K
81-300SD 217K (Wife's)
79-300CD 212K - Project
89-Volvo 245 305K

VCV is fine.

Now, you simply need to plumb it properly with a suitable orifice in the supply line to the VCV and all will be well. 10" vacuum is an excellent place to start.

Any sign of that orifice? If not, you'll be visiting a junkyard soon.

I found a yellow orifice that was on one of the "T"s I took off. It is the only orifice on any of the connections.

Where would it go?

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84-300D 256K
81-300SD 217K (Wife's)
79-300CD 212K - Project
89-Volvo 245 305K

It goes in the vacuum supply line just before the T above the VCV. The VCV/modulator circuit must have reduced airflow or the VCV can't work properly.

Well, now it is driving smoother, except from a dead stop , it lags until it hits about 1800-2000 rpms (about half of the time) and then goes into gear.

This is very similar to the initial problem. Can this be adjusted?

Brian, thanks again for your time and input.

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84-300D 256K
81-300SD 217K (Wife's)
79-300CD 212K - Project
89-Volvo 245 305K

As explained in post #38, the failure to engage first gear is not a vacuum problem. The vacuum can serve only to modulate the shift speed so that the shift is not too harsh.

If it won't go into gear until you hit 1800 rpm's, then you've got internal problems with the transmission.

Don (or Brian C.) ;

I'm a newbie who has been reading this post with intrest, as I am attempting the B-2 piston repl. myself. Had the "classic" B-2 piston failure systoms on my '84 300D - pulled the piston out -(broken) - and am having a real tough time pulling out the black seal in front of the metal bushing ( to be replaced with the plastic one). Is there some trick or do I just jam a sharp tool into the seal & pry it out? I've pretty much chewed up the seal trying to get it free & don't want to damage the surrounding case. How did you get yours out?

TIA

I'll let others who have actually done that task comment on it. Fortunately, these three have held up well regarding the trans.........

TIA

I don't know if I am the right person to give advice with my track record of ignorance, but here goes.

I would not put a screwdriver in there and ding everything. I used my fingers (for almost an hour) one of the times and the other two times I used a short wooden dowel to help maneuver it out. When you put it back in, be careful that you seat it all the way in (or your dogbone will not totally engage and you will have no movement) and that you don't damage the black teflon ring by using something to force it in. Mine was very difficult to put in all the way and evenly.

I hope this helps...nothing else has worked for mine.

Don

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84-300D 256K
81-300SD 217K (Wife's)
79-300CD 212K - Project
89-Volvo 245 305K

Thanx, Don - I'll give that a try. By a "short wooden dowel" I assume it was just smaller than the inner diameter of the seal and you worked it back & forth until the seal came loose....?

This is what I used to pull both bushing and seal together: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=4876
I tied a rubber band at the end of the claws so that they would open at the same time.

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'85 300D Cal 280,000 miles
'14 GLK 350 60000 miles

It could be the B2 band is worn out. Have you tried using a longer thrust pin(dogbone)? I had similar symptoms on my car before I finally broke the band.

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'85 300D Cal 280,000 miles
'14 GLK 350 60000 miles

The thrust pin comes in a few different lengths. There is supposed to be a way to measure the size needed. The ATSG manual I have goes through the steps needed to determine the length required. I wish I could scan the page and post it.

__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012

I took a couple of photos of the two pages.

__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012