Vacuum pump issues

[ezgn]

I checked the vacuum on the pump at the 3/8" fitting and it holds at a steady 26. At the small line going from the pump to the vacuum switch it flucuates rapidly from 18-14. Coming out of the vacuum modulator to the tranny is a steady 11. The truck is a 1986 M1008 shifts at 15 and 35. Any help would be appreciated. The lines are all new and tight.

 

[Russm]

From your description I don't see any issues. I've adjusted mine to also shift at 15 and 35.
Are the shifts rough or causing concern somehow?

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[ezgn]

From your description I don't see any issues. I've adjusted mine to also shift at 15 and 35.
Are the shifts rough or causing concern somehow?

Sent from my LM-G710 using Tapatalk

My concern is that it fluctuates rapidly between 18 and 14 and I was wanting to know if this was normal or a symptom of the vacuum pod getting weak. Thanks

 

[cucvrus]

I agree with the previous poster. If it shifts fine and you have no negative problems keep on going. What is the concern? It will fluctuate it is on a distributor drive with a diaphragm. Finding new ones is getting hard. Are you having issues? If you dig deep enough you will find more problems. But if it were mine and everything was shifting fine I would drive on. That vacuum system works fairly easy. I usually get a local transmission shop to set mine up if I have issues with the shift and not shift. Works out better for me and is $20-$40. well spent. Good Luck.

 

[ezgn]

I agree with the previous poster. If it shifts fine and you have no negative problems keep on going. What is the concern? It will fluctuate it is on a distributor drive with a diaphragm. Finding new ones is getting hard. Are you having issues? If you dig deep enough you will find more problems. But if it were mine and everything was shifting fine I would drive on. That vacuum system works fairly easy. I usually get a local transmission shop to set mine up if I have issues with the shift and not shift. Works out better for me and is $20-$40. wel

 

[Curtisje]

Mine also shifts at 15 and 35. No problem here.

 

[ezgn]

Thanks for the help. I didn't know that the vacuum pump readings fluctuates. I feel some relief. I know the pumps are getting scarce so I thought I should grab one for insurance.