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5MT D/R difficult to get out of 4hi

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So I have been able to actually test the 4wd in my recently installed 5MT D/R and found that getting from 4hi to fwd is more difficult than I think it should be.

once in 4hi it will shift to 4lo and back with no problem, the difficulty comes when you shift from 4 hi to fwd.

I have tried all different scenarios: engine on, off. clutch in, out. rolling or stopped. the only way I can get it to go back to fwd is to roll slowly 2-3mph clutch in in neutral and force the lever down. it makes a loud banging noise when it disengages. I have only done this twice, I am trying to keep from damaging it.

 

I am pretty sure that all 5mt D/R are a 3.90 final drive, the rear diff in my car is a 3.90. The trans has 23 spline axle shafts so i am 99% sure it is from a non-turbo car. Is it possible that a JDM trans (from japanese engines) could be a different ratio?

thoughts?

 

Ben

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Sounds to me like either the tires are different sizes, or something along those lines. You're driving in a straight line while attempting to get back to fwd I'm assuming, right?? Maybe some sort of issue with the linkage?

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Sounds to me like either the tires are different sizes, or something along those lines. You're driving in a straight line while attempting to get back to fwd I'm assuming, right?? Maybe some sort of issue with the linkage?

 

the tires are all brand new 195/60-15. Driving in a straight line, yes. As I described in post #2 I can't see the linkage being out of adjustment, that is why I was thinking different ratios in the rear diff and trans.

:banghead:

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What surface are you on when you do this? Dry pavement will bind pretty easily, but if you're getting these symptoms on ice, you've got a pretty big problem.

 

But it's definitely binding up.

 

This means the front and rear pinions are trying to spin at different speeds.

 

This can be caused, obviously, by different gear ratios. The only 3.7 PT4WD D/R I know of was in the 85 and 86 RX, which would definitely be 25 spline. So you're probably right on the trans. How sure are you of the rear diff ratio? I'm assuming if it came from the same car you would have said so...

 

Or, if the front and rear wheels are spinning at different speeds. Meaning their average circumference is different. If you're experiencing this symptom on dry pavement, it could just be a slightly different tire pressure....

Edited by Numbchux

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YES, a JDM trans has different ratio. I re-read your post. You have a JDM trans in there, then your ratio is wrong//

 

You need to test this with the car off the ground, all four corners on jackstands. see if you get buttery smooth disengagement. If so, then verify gear ratio is same. verify tires are same. If same, then all is normal.

 

You are not supposed to shift in and out of 4wd when on dry pavement or non slipping surfaces. meaning gravel is ok to shift in and outm same on snow or ice, Not on dry pavement. The owners manual should clearly state this.

Edited by bheinen74

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drive backwards in circles to free it up. If you can reember your maneuver after you engage the 4wd, you can litterally reverse your course to unwind it. You might have to goose the clutch or throw the car around and make it drift a little to lose the bind.

 

If the tires are in question, mount them diagonal to their current locations.

 

4wd can be used on snow, sand, grass, gravel. In rain, on highway at highway speeds is ok, but around town not so much.

 

so what would be the ratio for this jdm trans?

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What surface are you on when you do this? Dry pavement will bind pretty easily, but if you're getting these symptoms on ice, you've got a pretty big problem.

 

But it's definitely binding up.

 

This means the front and rear pinions are trying to spin at different speeds.

 

This can be caused, obviously, by different gear ratios. The only 3.7 PT4WD D/R I know of was in the 85 and 86 RX, which would definitely be 25 spline. So you're probably right on the trans. How sure are you of the rear diff ratio? I'm assuming if it came from the same car you would have said so...

 

Or, if the front and rear wheels are spinning at different speeds. Meaning their average circumference is different. If you're experiencing this symptom on dry pavement, it could just be a slightly different tire pressure....

it was on wet pavement , I know that's not the same as snow/ice or gravel.

the diff ratio in the car is the original, 91 Loyale that came with a 3AT, 3.90 is what is on the tag.

 

YES, a JDM trans has different ratio. I re-read your post. You have a JDM trans in there, then your ratio is wrong//

 

You need to test this with the car off the ground, all four corners on jackstands. see if you get buttery smooth disengagement. If so, then verify gear ratio is same. verify tires are same. If same, then all is normal.

 

You are not supposed to shift in and out of 4wd when on dry pavement or non slipping surfaces. meaning gravel is ok to shift in and outm same on snow or ice, Not on dry pavement. The owners manual should clearly state this.

 

this is not the original trans, I swapped it from a 3AT so I do not have the owners manual since you couldn't get the Loyale with a D/R...

Do you know what the JDM ratio is? I have looked and looked and all I can find is 3.90 for the PT D/R.

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Mine's bone stock and does the same thing. Reversing a couple of feet usually unbinds it right away..

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4WD with a hi-low gearbox should only be accessed on snow, ice, gravel or mud; or any really really really slippery surface. Pavement, whether wet or dry will cause the drivetrain to bind up; don't do it since it will damage the car if you leave it long enough. The downside to the gearbox you have is that you'll normally always be in FWD; the upside is that it's great on mud and snow. Live with it.

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I hadn't realized that it would bind up that easily...

I will have to just get used to it.

thanks for the input everyone.

 

 

I am still curious if the JDM transmission actually has a different final drive ratio than 3.90.

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as stated, pavement is not recommended, unless its 70 mph in heavy rain with hydroplaning, and you disengage before getting off the highway.

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They will bind up that easily even with a properly matched set of tires. There's a reason for the center diff in the AWD models.

 

Our second Subaru (first one with a dual range gearbox) was a 1986 GL wagon with 120K on when we bought it. It was in perfect shape and very clean and I thought I had checked it out thoroughly during the test drive. After paying for it and driving it home from West Seattle I realized I hadn't checked it in 4WD and engaged it as we approached the West Seattle bridge. Going uphill, the car became very sluggish and didn't seem to have any power. I had to drop it into 2nd gear just to maintain 25mph! I managed to get it back into FWD and made it home without any issues. I thought I had gotten a lemon until I found this Board and got "educated" on the dual range transmission and the technique for getting it out of 4WD when it seemed stuck.

 

As to your JDM transmission, find the identification label on it (something like TY752VB4BA) and post it here. Someone may be able to identify which ratio it is for you. The label is located on the bell housing near the starter motor.

I hadn't realized that it would bind up that easily...

I will have to just get used to it.

thanks for the input everyone.

 

 

I am still curious if the JDM transmission actually has a different final drive ratio than 3.90.

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If you swapped from a 3at double check your rear ratio. All 3at's used 3.70 ratio except the 3at turbos which used a 3.454 ratio. All dual range 5 speeds used a 3.90 ratio except the dr used in the RX which used a 3.70. This is per the ea82 service manual available here on USMB.

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I have the same trans in my brat same issue only not as bad as you describe I find that if i shift from 4wd high to fwd while the clutch is engaged aswellas backing off the throttle it shifts smoothly

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as stated, pavement is not recommended, unless its 70 mph in heavy rain with hydroplaning, and you disengage before getting off the highway.

 

Isn't it a bad idea to use 4wd in the rain? In my mind, I see going around a slight curve on the highway at 70 mph in rain a dangerous time to have all 4 wheels locked together.....

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They will bind up that easily even with a properly matched set of tires. There's a reason for the center diff in the AWD models.

 

Our second Subaru (first one with a dual range gearbox) was a 1986 GL wagon with 120K on when we bought it. It was in perfect shape and very clean and I thought I had checked it out thoroughly during the test drive. After paying for it and driving it home from West Seattle I realized I hadn't checked it in 4WD and engaged it as we approached the West Seattle bridge. Going uphill, the car became very sluggish and didn't seem to have any power. I had to drop it into 2nd gear just to maintain 25mph! I managed to get it back into FWD and made it home without any issues. I thought I had gotten a lemon until I found this Board and got "educated" on the dual range transmission and the technique for getting it out of 4WD when it seemed stuck.

 

As to your JDM transmission, find the identification label on it (something like TY752VB4BA) and post it here. Someone may be able to identify which ratio it is for you. The label is located on the bell housing near the starter motor.

 

I looked today for the ID tag but it was unreadable, but I think it is working as advertised. Since I did not have an owners manual that covered the D/R transmission I assumed it worked like any other "shift on the fly" 4wd, but I know better now.

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I looked today for the ID tag but it was unreadable, but I think it is working as advertised. Since I did not have an owners manual that covered the D/R transmission I assumed it worked like any other "shift on the fly" 4wd, but I know better now.
Good, I was hoping we could identify the gearbox, but as long as it works that's all that's important.

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So I thought I'd put my 2 cents in. When I got my car It did exactly what your describing, it was because I had a 3.90trans and a 3.70 rear diff. I put the diff From the donnor car in and with correct ratios it pops in and out very easily and it does it on dry pavement just as easily. i drive it like a rally Car every day 5000 miles Not one complaint.

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And if you wanna test it put it in 4wd and drive off a small lip if when the front wheels start to fall the car lunges forward or backwards you got the wrong ratios because my rear diff was a higher gear mine lunged forward a lil If it's lower youll lunge back a lil. driving like 5mph off a pavement break works good you just wanna make sure both front wheels leave the edge at the same time this is what I did. And don't drive off like a curb or anything that's more than like 5 inches tall. be smart lol

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If you swapped from a 3at double check your rear ratio. All 3at's used 3.70 ratio except the 3at turbos which used a 3.454 ratio. All dual range 5 speeds used a 3.90 ratio except the dr used in the RX which used a 3.70. This is per the ea82 service manual available here on USMB.

 

This isn't true.

 

After 87, all NA 3ats were 3.9. The 3.9 on the cover confirms this.

 

But....since the covers can be swapped, and it could have happened, so I would perhaps pull the rear diff cover, and count the # of pinion teeth and Ring teeth.

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rehashing an old thread,

 

 

i have a similar issue, hard to get out of 4wd once engaged, sometimes can roll it back and forth to get it easier. could it be something like a shift bushings at all?

 

4wd drives and functions fine, i have a 3.9 rear dif (cars '92), has to be forced out of 4wd, no clunking or anything when it shifts as the OP of this thread had.

Edited by xbeerd

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