PC-85-928S

I have been testing all vacuum points with my new Harbor Freight Vacuum pump.
Everything held vacuum individually except the line to the transmission.
I bypassed the transmission line and applied vacuum at the main vacuum point where it connects to the rear of the throttle body.
It held pressure.
I had my transmission rebuilt apx 6 months ago, and shorly after it began shifting hard.
I thought I needed to bring it back to adjust the modulation.
Now I am thinking maybe the vacuum line has become disconnected somewhere.
Can the car be driven w/o the transmission vacuum connected, if I wanted to bring it to a shop with a lift?
Or can I jack it up and try and trace the line. I know it goes above the torque tube.
I want to check the connection at the transmission end on the modulator, I think I read it is on the drivers side.
I know some have run a new line avoiding the exhaust system.
What type of line did you use?
Any and all advice appreciated.

borland

Ask them why they didn't replace it when the transmission was out. They may need to remove the heat shield/exhaust to reach it.

Here’s what you need…. German 3.5mm I.D. cloth braded vacuum hose… $2.50 per foot, plus shipping.. Lasts 10 years..

http://www.ebay.com/itm/VW-3-5mm-Gas...acddb9&vxp=mtr

supercedar

On my 88 I can reach the modulator as is. I would put the gauge to it to make sure it is holding vacuum then troubleshoot the line. The line can come apart towards the engine side above the TT.
You can drive it as is, just be sure to shift it manually
Thomas

PC-85-928S

How many feet would you think for a new run?

borland

Not much. You could estimate the amount by crawling under the car, then upon install, use the old hose to cut to original length. It loops through a hole in the top of the tranny and down to the front as show here.





There is also a short piece (2") at the front of the TT which acts as a coupler between the hard line and the nylon line leading to the top of the firewall.

elgreco

Where in long island are u maybe u can bring it by my shop, and we take a look at it. I'm in smithtown

PC-85-928S

I am in yaphank

PC-85-928S

I can't really get to anything by jacking and crawling under.
I want to bypass the trans vacuum, so I can get the car running well enough to drive it.
Should I plug the trans vacuum line or leave it unplugged?
I was thinking of running a rubber two way splitter from the egr line.
The egr has it's own port from throttle body, so I thought it may be a good temp source of vacuum for the trans which I feel is leaking anyway

SQLGuy

For now, you should be able to plug the (5?) way manifold by the rear fuel pressure damper where the trans line plugs in.

PC-85-928S

I actually took the trans vacuum out of the main vacuum loop.
Ran it with a split from egr line.
Car is running well!
Not even shifting very hard, no more hunting idle.
I know it is a temporary fix, but that trans vacuum line is hard to get to without a lift.

elgreco

if you like im at 303 maple av smithtown ill be here all day. let me know if you need a lift

PC-85-928S

Are you doing the captree run in the am?

elgreco

ill be there

Otto Mechanic

I was able to remove the standard heat shields (again) to expose the braided cloth vacuum line connecting the hard line to the poly line from the engine bay vacuum distributor. After replacing the 4 or so inches of braided rubber vacuum line connected to the hard metal line above the torque tube, I was unable to connect the new line to the existing poly line from the engine bay. I couldn't get my hands on both tubes with enough traction to connect them. Not enough clearance for my hands to gain a purchase. I enlisted my wife, who has much smaller hands. She couldn't do it either and elected to go clean horse stalls instead of helping. That should give everyone a good idea of the level of frustration experienced; she'd rather shovel horse sh*t than do this job. I sympathized.

I disconnected the new braided line from the hard line, then connected it to the poly line. After that, I connected the new braided cloth rubber line to the hard metal line. Viola! we had contact.

Today I test drove the beast and it shifted (again) like silk. Power was smoothly delivered to the transmission. Life was, once again, good.

Thanks to all of you for your advice and assistance. On to the next project, watch this space for further announcements?