High shifting point

[Indyharleyguy]

Hi All. My 1984 6.2L seems to rev up a lot higher before shifting than my old one. Shifting from first to second revs up higher and it shifts into 3rd around 55 MPH. Wanted to see if you'd give me some ideas on what to check? Thanks

 

[WWRD99]

Hi All. My 1984 6.2L seems to rev up a lot higher before shifting than my old one. Shifting from first to second revs up higher and it shifts into 3rd around 55 MPH. Wanted to see if you'd give me some ideas on what to check? Thanks

Can adjust the vacuum switch on the ip some or get an adjustable vacuum modulator for the trans...get more out of the ip adjustment though...doesn't hurt to have a vacuum gage hooked up to the output of the modulator and set it at 11 lbs. I set mine there and first shift is around 25 30 and 3rd is 40 45...depending on throttle.

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[Mad Texan]

Check/ replace the vacuum line to the vacuum modulator....

 

[Indyharleyguy]

Can adjust the vacuum switch on the ip some or get an adjustable vacuum modulator for the trans...get more out of the ip adjustment though...doesn't hurt to have a vacuum gage hooked up to the output of the modulator and set it at 11 lbs. I set mine there and first shift is around 25 30 and 3rd is 40 45...depending on throttle.

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Thanks for the info. That's way over me head though. Can you go into a little more detail? Thanks

 

[WWRD99]

Sure! You'll need a good vacuum gage...-0 to -25 in lbs tops...you'll hook that up to the modulator on the ip...I can't remember exactly on the top of my head which one...there's only 2 lines...if you get the wrong one though you'll see about 20 inlbs..normal is around 18 up to 25...make sure you have that too...I think the top line goes to the trans but look and trace it down...you want the line that goes to the trans, not from the vacuum pump.

Start it up and see what you got...there's 2 small bolts holding it to the ip...can loosen them up just a touch and it will move...it moves in slots where the bolts are...I have a 1/4 inch drive swivel 10mm that can reach them with an extension...don't take the bolts out!! It takes some patience, but after a few tries, getting it at 11 or 12 seems to be a happy place. If you don't have vacuum at the ip modulator, then go back to the pump and see it you have vacuum there. So...if you already have 11 12 in lbs at the ip next step is at the vacuum modulator on the trans...it should be a steel line with a short chunk of 1/4 inch line to hook them together.

Pull that line off and make sure no trans fluid comes out. If it does, you need a new modulator. Either way, put the gage on that metal line and see what vacuum you have. If you have 11 12, you might still need the trans modulator...if you have 18 25 then switch the 2 lines on the ip modulator and your done.

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[Indyharleyguy]

OK that's down from the 5000 ft level to the 1000 ft level thanks. I'm looking for a YouTube video to see if it brings it to my level.

 

[WWRD99]

OK that's down from the 5000 ft level to the 1000 ft level thanks. I'm looking for a YouTube video to see if it brings it to my level.

You can do this in the opposite direction as well ...it'll tell you if you need to adjust the ip modulator or just swap the lines...start at the trans vacuum and work your way up.

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[Indyharleyguy]

You can do this in the opposite direction as well ...it'll tell you if you need to adjust the ip modulator or just swap the lines...start at the trans vacuum and work your way up.

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Hey all. I'm just getting back to this. As it turns out, I appear to be really low on transmission fluid. I have bought a quart of it, put it into the transmission, and it is still not registering on the dipstick. I'm going to put another quart or so in and see if that helps everything.

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[cucvrus]

check your transfer case. I have had oil from the transmission go back and over fill the transfer case. I sent it to an Automatic Transmission shop and had it repaired and had them service the transmission and adjust the shift points. It worked perfect after that. Somethings I am not so willing to mess with and leave it up to trained qualified professionals. Have a Great Day.

 

[Indyharleyguy]

So I've put 3 quarts of transmission fluid in and its still not showing on the dipstick. The engine is hot and it's in park. I do not have any leaks and it's not in the radiator. Any thoughts of where it went? How many quarts does it hold?

 

[Tinstar]

Keep adding until it reads on the stick
Hopefully your transmission pump isn't toast.
It's either going to go on the ground, which you said it isn't, or it's in the transfer case as already mentioned above.
I would check your radiator cooler. Make sure it isn't leaking inside the radiator.

I would also drop the pan and change the filter once you get it figured out.

 

[cucvrus]

At the cost of ATF, I would first remove the 30MM fill nut from the transfer case with a catch pan right there. It flows out I would stop and seek expert services on the transmission and transfer case. If you keep running it ill, it will cost even more to fix. Broken case or whatever else goes wrong. I tend to overhaul things before they become useless. It has saved me lots of down time and money. Good Luck.

 

[DeadParrot]

Normal amount for a filter replacement is 4~5 quarts. Total capacity is around 12~14 IIRC. A lot stays in the converter during a filter change.
Might verify that the dipstick is proper for a TH400 transmission.

 

[Indyharleyguy]

Well it never showed on the dip stick. It did over flow though. Now shifting into 3rd revs up really high before it shifts. I can shift from 2nd to 3rd manually just fine. I'm going to take it to a transmission shop to see what they think has happened. Thanks all