Vacuum pump woes...:mad:..

[diesel4me]

It appears the vacuum pump on my 6.2 is dying,its only making 5" of vacuum--and its making the TH400 not want to upshift right,especially the 2nd to 3rd gear shift--now, the tranny sometimes seems to "slip" into a neutral state,after it finally goes into 3rd gear around 40 mph...it doesn't do that every time,most of the time once it goes in 3rd it stays in fine,and it shifts very firm..

I'm not sure if the trans has been fatally wounded ,or if it'll go back to "normal" once I get the proper amount of vacuum to the modulator...

The VRV valve (vacuum regulator valve) that controls the vacuum signal to the modulator was not working right when I got the truck 11 years ago,and adjusting it proved fruitless,it wouldn't maintain the vacuum signal,you could adjust it and get it to shift properly ,then it'd start dragging out the shifts again..

At the advice of a local trans rebuilder,he suggested I hook the modulator directly to the pump,then screw in the little adjustment screw in the modulator hose nipple till it just bottomed out,then back it off slightly,until the shift points seemed "normal"..he claimed that is what he's done on several trucks similar to mine,and had no comebacks..

I did that,and it has shifted OK since...until recently when the pump evidently started losing vacuum..

I do not know what year my 6.2 is,it was a salvage yard engine someone swapped in before I got it--I see looking on google there was more than one type of pump,some look like a distributor,others bolt on to the intake differently...I tried to get a look at it,but I couldn't climb up in there after getting the air cleaner off to tell for sure which type it has..

I am also disgusted to see a new pump goes for 100+ bucks,so does a VRV valve,which is a lot more than I'm willing to put into the truck right now (would if I HAD the money),so a used one is most likely what I'll end up going with...but how do I determine what year the engine is,so I can get the correct pump?...

I have read online some claim a pump "pod" off a 7.3 Ford is the same thing and can be used on the existing pump drive...anyone here done that?..

I could swap the vacuum pump in my Suburban onto this truck if it were the same,but I'd rather not start cannibalizing that engine either--I need to keep it run-able so I can move it around the yard,and possibly use it to plow if the pickup craps out completely (the Burb has a 700R4 with issues too though,and now has rotted brake lines--for what it'll cost to get a decent trans in that thing and make it roadworthy,swap plates,etc,it'll be about a grand...)...

I'll have to pray the Th400 isn't fatally wounded once I get another working vacuum pump too...if it is,then the truck will either get taken off the road and be used as a "yard truck" only as long as 1st and reverse works OK,or parted out...
I'm in no shape to be swapping tranny's and engines any more...

I must say the setup GM devised with the pump and VRV valve is lame,mickey mouse at best,in my opinion...I wonder how many good TH400's got fried because of the poor control of the vacuum going to the modulator..

The more I look at the 6.2,the less I like it...this never would be an issue if it had a gas engine...though the engine hasn't given me that much grief,I'm not really fond of it either...

I'm wishing you could still buy a carbed V8 around here for 200-300 bucks like you used to be able too--I'd be happier with a 350 in it right now,gas is cheaper,and this diesel might not last much longer thanks to me not being able to maintain it properly...

Been thinking maybe I should just sell all my junks,and pay someone else to plow my driveway...trucks in worse shape than mine on craigslist with a plow are listed for 1500+ bucks...

 

[diesel4me]

63 views,and no one has any experience with vacuum pumps?...huh...

I spent most of yesterday afternoon searching a junkyard for a 6.2,closest thing I found was a cannibalized turbo'd 6.5 in a 90's Suburban--it had a belt driven vacuum pump...

I have spent hours online trying to see if anyone has successfully used an electric vacuum pump in place of the mechanical ones,a few diesel forums had posts saying later Ford diesels had electric vacuum pumps ,and Dorman now sells them,for about 55 bucks...I'd convert my transmission modulator to run on an electric pump if I knew it would last--no other accessories on my truck need vacuum,no A/C or EGR,etc,so the modulator would be the only thing it would be operating..

I did see a few Ford 7.3's there at the junkyard,that had a very similar looking vacuum can on them as mine--also found an unknown diesel engine all apart in a truck body that had a distributor looking pump much like mine,but it didn't look to me to be a 6.2,it did have a chevy looking bellhousing pattern though..maybe a 6.9 IHC?...I could have bought that one for 40 bucks,but decided to wait and see if I can find out for sure if it'd work for me or not..

The vacuum pump canister "pod" on some other diesels like Fords are supposedly "useable" on my old distributor drive housing according to some posts I read on a diesel forum,but they dont go into great detail--looking up new ones,I see several different part numbers,that do look very similar.....but I didn't want to pay 40 bucks for something that "might" work,or end up being dead from sitting a long time...

Meanwhile,my engine is getting a beating over-revving it to get it into 3rd at 45 mph,and being "stuck" in 2nd around town..

 

[6.2 man]

If you go to NAPA they have both pumps .Vacuum and electric . Good luck

 

[brian wafer]

you would not have a picture. i have a old one,i give it too you. but not sure if its right model.

 

[diesel4me]

I haven't pulled it out yet,because I need the truck useable for short runs to get food and do errands,but I believe all the 6.2's with a rear mounted vacuum pump are the same...it'll look like this one below...

I've looked online,and the cheapest place to buy just the vacuum "pod" alone,is Rock Auto and a few other places ,for 80+ bucks...so I'm not too keen on paying 40 for a salvage yard one that might not last or be junk to begin with..(but I dont have a credit card or paypal,so buying online will be a hassle)..

Locally I can buy a rebuilt unit at Autozone for 110 bucks plus a 5 dollar core,special order--Advanced Auto wants 135 bucks + 15 for the core for the same unit,A-1 Cardone brand,which I've heard aren't as good as they once were..if I had that much money, I'd just go buy one there...

I'd go electric instead if I could be sure it'd last awhile--its not like I go hundreds of miles a day in this truck,but I'm not sure if they are "continuous duty" rated or not...seeing electric fuel pumps run constantly,I suppose a vacuum pump might be able too also?..

For 50 bucks I can buy a new electric pump and a wide range adjustable modulator for the trans,about the same as what the vacuum pod alone costs,and I'd avoid having to crawl on top of the engine and spend an hour lying on it ,trying to get the oil pump drive to align and get the new pump or pod installed..a chore I'd rather avoid if possible..

 

[Greg Ducato]

I don't think an electric pump would work since you would have no way to regulate the vacuum signal to the trans, you would end up with low pressure and stacked shifts.

 

[diesel4me]

I've fiddled with the VRV valve,and think its working ,it might have been the pump dying all along that made it appear defective----or I can repair it if its not working,a guy I talked too yesterday told me it has a rubber gasket and o-ring that fail,he's had issues with one on his diesel before,and has taken it apart and fixed it--also I found a used one at the junkyard maybe I can score that might be good too,if I can get them to sell it separately from the injector pump....

I suppose just replacing what's there is the simplest solution..but the vacuum pumps aren't noted for reliability or long life ,from what I have read..

I've also read some threads on dieselplace claiming some have modified the govenor weights to force a quicker 1,st to 2nd to 3rd shift, and dont even use vaccum to the modulator..or they went with the Humvee or aftermarket modulator thats cable operated instead..

I could live with the delayed shift from 1st to second,but not being able to get into 3rd until I hit 45 (with a hard shift!) gets very annoying in city traffic,and I'm not doing the engine any good racing it almost to the redline to get it to shift either..it'll probably spin a bearing next,right after I get the shifting issue taken care of....

 

[brian wafer]

sorry its the right one ,but its gone. i forgot i gave it ,a few years ago to a old guy. it was on a old motor that i kept. the motor ran when i pull it,but had atleast 3 cracks in the mains bearing. have a happy new year .

 

[Greg Ducato]

Robert, you can definitely add weight to the governor to get a quicker shift sequence if that is a viable solution for you. You will be adding weight to the inner weights themselves or you can use stiffer springs. I can probably whip one up for you,it may not be exact since we don't have a way to test it in your vehicle, but we can get a lot better than what you have now, PM me your mailing address if we can help here.

 

[diesel4me]

Brian,thanks anyway for the offer!..I appreciate you being willing to help..

Greg,I will PM you and we'll discuss the govenor mods...I dont mind the tranny shifting harder,I just want it to upshift sooner,especially into 3rd gear..

The TH400 in my truck is not a K case 4x4 one,I suspect someone put a short tail car or 2wd tranny with the correct output shaft for a NP-208 T-case in it before I bought the truck,supposedly it was rebuilt and installed just before I bought the truck--it has no provision for the two round braces that go from the motor mount pads to the dust cover,so they were just tied out of the way--it has a tin dust cover,not the cast aluminum 4x4 style one..

It has the diesel 6 bolt torque converter,but who knows what is in there for the govenor,it could be from its original application, car with tall gearing probably?..my truck seems to have "highway gears",it probably has 3:23 or 3:42's in it I'm guessing,going by how it sounds at 65 mph..it isn't screaming that bad,so I doubt it has 3:73's or 4:10's...

..I've tried looking online to see if there is any specs as to what difference the diesel govenor has vs a typical gas engined trans,but there is no real explanation,all I find is threads saying "the diesel has a specific torque converter (6 bolts & lower stall speed),and a "different govenor",but there is no details about just HOW the govenor is different..(most likely heavier weights ,etc,as you say..)..

 

[Mikey von]

Do you still need a vacuum pump? I have a small collection of 6.2L parts and I am sure there is a vac pump or 3. One of them can be yours for the cost of the ride.

 

[longbedder]

We're talking about a diaphragm-type pump that's probably 30+ years old...I realize it sucks for you now but you have to have realistic expectations.

You can get a mechanical modulator for the TH400 that deletes the need for vacuum altogether. New they're a little over $100, but early 6.2l HMMWV's and box trucks with 4BT diesels also had them, so you might be able to find one used/salvage.

http://www.ebay.com/itm/TH350-TH400-Cable-Operated-Modulator-350-400-/131285785490

 

[diesel4me]

We're talking about a diaphragm-type pump that's probably 30+ years old...I realize it sucks for you now but you have to have realistic expectations.

You can get a mechanical modulator for the TH400 that deletes the need for vacuum altogether. New they're a little over $100, but early 6.2l HMMWV's and box trucks with 4BT diesels also had them, so you might be able to find one used/salvage.

http://www.ebay.com/itm/TH350-TH400-Cable-Operated-Modulator-350-400-/131285785490

I am aware of those mechanical modulators,I mentioned them in post #7...thanks for the link anyway though...the problem with one of those is I'd have to source a TV cable and bracket for my engine,there is none on it,there was a chopped off TV cable lying in the valley,but since the truck has a TH400,whoever put the engine in probably removed the bracketry..
The truck isn't really worth buying 150+ bucks worth of parts ,so I was looking for a cheap fix just to keep it driveable..

Your right about the pumps being "antique",the one on my '85 Suburban's 6.2 turned out to be a dud also,I was tempted to "borrow" it for the pickup,but its NG too.....

Greg Ducato has helped me out a great deal,he sent me a govenor he modified with heavier weights, and a spring to install on the modulator spool valve in the transmission--I got both parts installed monday right after UPS showed up with them,and now the trans shifts into second around 20 mph,and into third around 33-36 mph,much more bearable than 45+ mph!...


Greg is "the man" when it comes to automatics...I wish he was closer,I'd have him rebuild the 700R4 in my Suburban...

I'd still like to get a vacuum pump,seeing both trucks need one now though--the Burb needs one to operate the defroster ducts..

 

[kennyw]

The truck isn't really worth buying 150+ bucks worth of parts ,so I was looking for a cheap fix just to keep it driveable.

While you may not be able to get that $150 back out of it, it is worth spending $150 to have a running and reliable vehicle when you need to go farther than you can walk in the ice/snow.

 

[campfire]

We're talking about a diaphragm-type pump that's probably 30+ years old...I realize it sucks for you now but you have to have realistic expectations.

Actually, I think the problem is that it doesn't suck.

 

[tRustyK5]

Greg Ducato has helped me out a great deal,he sent me a govenor he modified with heavier weights, and a spring to install on the modulator spool valve in the transmission--I got both parts installed monday right after UPS showed up with them,and now the trans shifts into second around 20 mph,and into third around 33-36 mph,much more bearable than 45+ mph!...


Greg is "the man" when it comes to automatics...I wish he was closer,I'd have him rebuild the 700R4 in my Suburban...

I'd still like to get a vacuum pump,seeing both trucks need one now though--the Burb needs one to operate the defroster ducts..

Greg is good people for sure, glad he hooked you up with something that'll work!

 

[longbedder]

Actually, I think the problem is that it doesn't suck.

 

[diesel4me]

While you may not be able to get that $150 back out of it, it is worth spending $150 to have a running and reliable vehicle when you need to go farther than you can walk in the ice/snow.

I could likely get more than 150 bucks for it ,with a plow and in "useable" condition a 4x4 here is hard to buy for less than 1000 bucks,even ones in worse shape than mine is...(though few on craigslist are actually selling for that much)..but I hate to part with it for 500 or less,which is what most here would offer for it as-is..

I just hate to spend a lot on it and fixing all its little sins only to have the engine or tranny crap out in it,then it will only be worth 150 in scrap...

The inner and outer front fenders are pretty rotted now,the rocker on the drivers side is patched up with tin,and the roof on the truck was stoved in and covered with 1" of bondo across its entire width before I got it,and the 8' stepside bed is about shot too,rust ate away the fuel filler door on the right fender,and the left one is about to come off in my hand too--left rear fender is stoved in,and the wood floor in the bed has dissapeared up near the cab,I had to put metal sheets over it..(I have a flatbed I could put on it,the bed isn't really a big deal to me..the cab and nose are--the doors were also patched across the lower 6" too..)..

The poor truck has suffered a long time under my ownership,yet its still hanging tough...had it 12 years now,and it's plowed at least 50 bad storms..

I cant really bitch about it not being reliable or durable,after what I've put it through,I should have more faith in it--but I haven't really given it the best of care either...mostly due to lack of funds,not because I dont care about it..


I've not been able to replace the rotted oil pan going on 4 years now,I just kept slathering more J-B Waterweld putty on it,that slowed the leak to a drip...loses a quart every few days.. ,and having no income for a long time till recently,I started adding used oil I strained through some cheese cloth and old nylon stockings,to avoid buying 15W-40 at 5 bucks a quart,to keep it topped off,and hopefully not do more harm by running it low on oil..

The oil I've been adding is a mixture of whatever came out of later model cars from my friends shop,probably 5W-20,5W-30 and 10W-30 and some was probably synthetic,and some wasn't...it still looked very clean,and if anything,my 6.2 seems to start much easier in the cold and not sound as horrible after a cold start so long..the pressure has dropped maybe 10 psi,but other than that,it doesn't seem to be doing it any harm,but I'd still prefer to be using correct "diesel rated" oil in it...and will,as soon as I can keep it IN the engine...


I also by-passed the oil cooler with copper tubing after the lines rotted away on it..that hasn't seemed to phase it any..

The fuel tank now weeps,and the sending unit in it doesn't work,so that'll need to be dropped and fixed or replaced,and the frame seems solid,but has gotten thin in places and I'd hate to spend a lot of money on the engine or tranny and have it end up cracking or rotting through in a critical spot...the truck isn't really worth an engine swap now in its present condition..but I'd probably be stubborn enough to do one anyway--anyone else would have scrapped it years ago...

I also only drive it maybe 50 miles one week out of the month,the rest of its use the rest of the month is limited to short local runs to the market or landfill,etc..

I'd be more willing to invest time and money on my Suburban instead,and just use the pickup as a yard mule, than fix all it needs now,but if I dont do something with it soon,it'll not be in any better shape than the truck is...it has already lost the brake lines from sitting,it is starting to rot the rockers out,they were mint when I got it....

...the biggest drawback to it is the 700R4 in it needs a rebuild or swap,and I'm not up to that task...and probably wont be able to scrape up the money to get a good used one and have it put in--just putting it on the road will cost as much as I paid for it to start with..

If I didn't have to pay a grand every 4 months for property taxes,with a monthly income of less than $850, none of this would be an issue,I'd have the cash to make all these problems dissapear...and fix the roof on the house too.....

 

[campfire]

If I didn't have to pay a grand every 4 months for property taxes,with a monthly income of less than $850, none of this would be an issue,I'd have the cash to make all these problems dissapear...and fix the roof on the house too.....

I know I've asked this before, but what keeps you from leaving the expensive real estate? There are plenty of cheaper places to live...

 

[Mikey von]

Vacuum pump is on the way. My treat!