Driveline issues on 2002 impreza transplant into 87 ea82t

[ea2ej fingers x]

Hello all. I'm vexed and out of my depth. Basically I have transplanted the 2002 wrx engine/manual tranny/rear differential/and rear cross member into my 87 wagon (ea82t). In terms of drive line, what remains of the 87 is the propeller shaft (minus 50 mm), everything outboard of the front transmission drive splines, and everything outboard of the rear inner cv cups.

 

It is driving, just not well. It feels like there is a brake on when I drive it and when I get it back into the drive way and turn it off, then back on, it won't drive at all. I go to release the clutch in gear and the car bogs down and stalls. If I put the car in neutral and try and physically push it, no dice. If I jack up either end of the car I can rotate the wheels freely. Once again it will drive around the block, albeit with serious drag, until I park it and then I'm back to square one.

 

I did some rough drive angle calculations and it seems to be within tolerances. However, I did take the propeller shaft mounting flange off the 2002 differential and replace it with 87. It seemed to be a perfect fit, but I'm not sure if this is something that could cause a problem.

 

The tires are oversized, but all the same size and evenly worn. There is no shudder or vibration, just drag. All tires, half axles and cvs spin with little resistance when off the ground. All bearings are new.

 

The engine and rear differential are from two different 2002 wrx's, one sedan, one hatch back. Is it possible that two different body styles of the same year model have different gear ratios?

 

Sorry, I know I'm getting long winded, but I think this may be important information. I mentioned before that everything outboard of the rear inner cv cup was from the ea82t. Basically, I separated the inner cv cup off of the 02 half axle, did the same with the 87, and mated the rest of the 87 axle to the 02 cup. The resulting half axle was 1/4 inch shorter than the stock ea82t. After all the fabrication and welding required to mate the 02 rear diff and crossmember to the 87, the diff was positioned 1/4 inch toward the driver side of center. This essentially made a perfect fit for the driver-rear half axle, but too much of a stretch for the passenger half axle (there is a 2 inch suspension lift on all four tires btw). However, this was solved as it turns out that the middle portion of a front axle (from inner cv cup to outer) from Subaru years 80-84 is a perfect match for the rear middle portion of an ea82t rear half axle, only 1/2 inch longer. To sum up, the passenger rear half axle in my car is now 1/2 inch longer than the driver, but the overall distance from hub to hub is exactly as it should be for the 2002 wrx. Could this discrepancy be the problem? Phew, I'll be shocked if any of you make it this far

 

Any experience, strength and wisdom you all can lend would be most appreciated.

[ea2ej fingers x]

Holy ************, I think I may have just thought of a simple and possibly awesome explanation for my problem (awesome in that it would mean I didn't screw everything up The hill-holder system!? During the conversion I cut the cable off it thinking "what's the point?". I don't fully understand the mechanism, but it sits right below the brake booster and I presume it applies a little brake when on a hill? I noticed I actually damaged the mechanism a little dropping my engine in, but figured it wasn't connected so who cares. Maybe? Anyone know how this would manifest my symptoms? Thanks again.

[tractor pole]

the hill holder could be your problem but I would still confirm that the diff ratio for the trans and rear diff are the same.

[presslab]

The engine and rear differential are from two different 2002 wrx's, one sedan, one hatch back. Is it possible that two different body styles of the same year model have different gear ratios?

 

I think this is your problem. Maybe your rear diff was from a 4EAT equipped car?

 

It's easy enough to pull the rear part of the propshaft to see if that frees things up.

 

If after you jack the car up and back down and it binds right away then the hillholder could be it. A difference in diff ratios would be evident after driving the car.

Edited May 23, 2012 by presslab

[ea2ej fingers x]

the hill holder could be your problem but I would still confirm that the diff ratio for the trans and rear diff are the same.

 

Will do, but I'm not sure how to. I can't find any literature supporting the possibility that the same model and year would have different gear ratios. Are there serial numbers on the trans and diff that can be cross referenced? Thanks for the reply.

[ea2ej fingers x]

I think this is your problem. Maybe your rear diff was from a 4EAT equipped car?

 

It's easy enough to pull the rear part of the propshaft to see if that frees things up.

 

If after you jack the car up and back down and it binds right away then the hillholder could be it. A difference in diff ratios would be evident after driving the car.

 

Thanks. Yeah, it's a bit befuddling because I don't hear or see anything release when I jack up the rig. I thought I might just remove the entire propeller shaft tomorrow and see if it drives fine in 2wd. If it does, I'll know the rear end is f-ed, and if it doesn't, hopefully hillholder and not transmission

[tractor pole]

Will do, but I'm not sure how to. I can't find any literature supporting the possibility that the same model and year would have different gear ratios. Are there serial numbers on the trans and diff that can be cross referenced? Thanks for the reply.

 

there should be a sticker near the starter on the transmission bellhousing, you can find out the diff ratio from that number(I am not sure of an online database but you could probably call the dealer). the rear diff should have a plate on the cover stating the gear ratio.

 

 

Ben

Edited May 23, 2012 by tractor pole
duplicate statement

[ea2ej fingers x]

Maybe your rear diff was from a 4EAT equipped car?

 

Sorry, missed this on first read. The differential was definitely from a manual trans, as I pulled it and the shifter/pedal setup myself. Thanks again for the reply.

[ea2ej fingers x]

Thanks Tractor Pole, I will look into it.

[Turbone]

Most of the newer Subaru's have no plate showing gear ratio.

You may have to remove the cover and count teeth, or remove both axles (quite easy) and see if it still binds.

Also cutting the cable to the hill holder should not effect anything, mines been disconnected for a quite a while. It would take a pinched brake line or the lever jammed closed to cause it to lock up the wheels. But then it would not matter if the car was jacked up or not (you said it free wheeled when in the air).

I vote for different gear ratios.

[ea2ej fingers x]

Excellent point Turbone. Though it got me thinking about how freely it moves in the air. Rears, totally free. Front, not entirely. I attributed this to the fact that, with the 2" suspension lift, the passenger axle actually contacts the crossmember when on jack stands. Now I'm thinking maybe it was more to do with the hillholder. I am going to do some research on the hillholder directly, but if it only acts on the front circuit of the brakes, I think this may still have some merit. Especially given your point about it being jammed forward as that is what happened when I installed the engine and trans (I actually had to bend the lever back into something approximating original form).

 

Obviously, I want it to be the hillholder rather than gear ratios Beyond that though, it makes no sense to me that a car manufacturer would build two cars in the same year, make, model, engine size/type, trans type, and then make a sub group of two different trans/diff pairings. Anyway, thanks for the reply. I'll let you all know what I find today

[Turbone]

Hill holder usually works on 1 front tire and 1 rear tire.

Wheels wont bind without a load most likely.

But I can see your point with the HH, hope its correct.

[ea2ej fingers x]

update: So I followed the hydraulic lines out of the hill holder and they appear to be going to both front wheels. Anyway, I removed the spring and cable linkage and cracked open both front bleeders. The passenger bleeder spit a good bit out. I released the parking brake and the car rolled easily in the driveway. I realize this is not conclusive by any means.

 

My going theory right now is that the twisted spring on the hill holder had it stuck slightly engaged and as I drove the brakes heated up and expanded creating more friction. Once stopped the static friction was too much to overcome until the brakes and wheels cooled down (well too much to overcome while being careful I'm going to test drive in a bit. We'll see

[wentz912]

Did you win?

[ea2ej fingers x]

Mother Father I did! Drives like a dream Man, I was all kinds of befuddled thinking I had just reduced my beautiful 87 into a pile of crap, but alas I don't have to surrender my wrenches just yet. The hill holder was the culprit. I spent the afternoon in the sunshine putting trims back on. Pretty awesome day.

 

Thanks to all for helping trouble shoot. Just when I thought technology was just out to ruin us, this forum comes along to prove me wrong. Seriously though, I've mostly been a browser on here for the past few months as I've toiled and tinkered away, but there are many awesome folks on here that are incredibly patient and giving of their wisdom. I'll try to stay tuned in and pay back any I can. Clearly I have a good buzz on. Promise not to say "I love you man". But I love you man

[presslab]

Nice job.

 

So it was a twisted spring on the cable linkage to the hillholder? Did you disable it or did you fix the problem?

[bratman18]

You should post some pics of the "new" ride! Congrats on getting the issue fixed.

[ea2ej fingers x]

I will for sure. I'm out of town for the weekend so won't be able to finish:( But I should have her all done by the end of next weekend and I'll post some photos. She's a beast!

[ea2ej fingers x]

Sorry Presslab, didn't see your post. Just disabled it. Technically it was disabled in the first place as I did a frankenstein blend of the pedal assemblies from the two vehicles (mostly to accommodate the pull type clutch with hydraulic ram, but also because I like the new pedals

 

I still don't fully understand the hill holder mechanism, but something was fouled up and I have faith in my ability to start on a hill

[ShawnW]

Nice job.

 

I am confident that there are many people that have learned a lot from people on this forum without ever posting too. Look at your project and progress with only 13 posts here. Amazing. People that are shy with the keyboard, people that just read and read and never stop until they find the solution. I wish people would come out and post even just a hello and a photo of their car more often.

 

PLEASE post photos when you can!

[Gloyale]

 

I still don't fully understand the hill holder mechanism, but something was fouled up and I have faith in my ability to start on a hill

 

it's a cylinder on it's side, with a ball inside it.

 

At the fluid entry end (back) there is a pin that keeps the ball from covering the fluid in hole.

 

The other end has a "T" that splits the line sends pressure to the front right, and back left. (newer legacy only front left)

 

When the cable get's pulled, the pin pulls back and the ball block fluid from escaping back to the master, basically becoming a one way valve.

 

Now, if the holder is on a flat, or pointed downhill, the ball won't roll backward......ussually. there are a couple ways that it can happen and interfere with normal driving.

 

1) mis-adjusted.....level wise. Shim a washer or two, under the back of the holder valve........this will make it so you need to be on a steep hill before it will work.

 

2) roll backwards quickly, hit brakes and clutch.......ball rolls backward, locks brakes.......release the clutch once, and they should release.

 

3) very fast acceleration....slings the ball backwards......if you hit the brakes in this condition, with clutch in...locks brakes.

 

 

any of these, should release when you release the clutch. I'm guessing you have or had the cable too tight. I would still suggest shimming a washer under the rear so it will not want to work on flats.

 

worst comes to worst, it can be eliminated with a simple "T" fitting.

 

Unless someone messed with it, the lines out of it go to the front left, and rear right.

[ea2ej fingers x]

Most definitely Shawn. My girlfriend has the same complaints about me talking through my problems I intend to be more active in the future and will post pics for sure.

[ea2ej fingers x]

Thanks Gloyale! That's amazing. I did a pretty decent search without having any luck finding information on the system. In the end, I decided to go with the T. Btw, you and Turbone were correct about the two tires it works on (I made a mistake last time I traced the lines), both those wheels were hotter than a pistol last time I drove it before eliminating the hill holder. The weird thing was, the hill holder was completely disconnected (other than being a pass through for brake fluid), you could turn the top hither and yon and it made no difference. It still grabbed after a couple compressions of the brake pedal. Anyway, thanks again for dropping the knowledge!