Hey everyone. Looking for a second opinion on an issue. I have a 90 Loyale Wagon. 1.8L TBI non turbo 5spd trans with hi/low range 4WD.Just recently went through the motor replacing seals and gaskets, and have replaced the fluids front to rear. Runs like a top in 2WD, no leaks and no problems. However when I shift into 4WD it feels like someone threw an anchor out the back or the rearend is dragging, and it is very stubborn to get back into 2WD to the point of nearly impossible unless you hit the perfect sweet spot. I read on here someone with a similiar issue that stated it was most likely because of being on dry pavement. While I can understand that turning, why would it cause a massive lack of power like that going straight at 25-35mph? Also I have noticed in several post here and the owners manual for a 92 loyale that you can shift into 4WD from 2WD while going straight but rolling. Does that also apply to the gearshift 4WD as opposed to the push button? I know on domestic 4WD ive always stopped completely to do this. Thanks for any suggestions. Love this car and every subaru ive ever had.

Tires all the same size and molage? Did you just get this car? Did it used to work normally?

 

You should be able to switch 4wd on and off at will going straight. No noticeable change in loading, if everything is correct.

Any gear oil in the rear differential?

i wouldnt put any vehicle in 4-wheel unless im stopped, but thats just me. i would do a complete check on trans fluid and rear diff fluid. since its having a hard time going back to 2wd i would guess its more transfer case/transmission oriented

One of the original Subaru selling points was shift on the fly into 4WD.  I do it frequently.  Get used to your car first, to be sure everything is correct.  Hard turns are not the best time to switch.  But straight cruising along, not heavy load, is no problem.  Everything is already turning at the same RPM anyway.

Indeed,the manual trannys have a synchro on the 4wd engagement gears.

 

Can`t see a lubeless rear diff being the OPs problem as the rear diff turns whether 4wd is engaged or not.

What ratio rear end is in your car. Should have a tag on it.

Linkage adjustment between 4wd hi and 4wd lo may be the solution. I have had the same feeling of "dragging an anchor" when the vehicle wasn't correctly in 4wd hi.

 

(I am running a Loyale 5 speed box in a Brumby (BRAT), but the same issue could apply).

Rear diff may be a different final drive ratio than the transmission.

 

It would do exactly as you're describing. Fine in 2WD and then crazy binding in 4WD.

 

If the trans or rear differential are known to have been replaced then that's likely.

Shifting fwd to 4WD while driving is no nig deal.

Just recently got it from a family member. Know the combination works since it was drove for years as is. However it sat for about 7 years before I got it. Mileage isnt known, as its had motors swapped and tranny came out of a DL I think. The gear ratio says 3.90 and yes it has fluid. Like I said, I put new fluids all the way front to back. Thanks for the suggestions.

motors swapped and tranny came out of a DL I think. The gear ratio says 3.90

 

"says" i presume you're reading the rear differential case sticker - which means the rear diff is 3.9, that's what the car came with and what we would expect.

 

if the transmission has a 3.7 final drive front differential then you have a mismatch and that's what's causing your binding.  

 

since the transmission has been replaced, that possibility is very high. 

+1 what grossgary wrote. When I added 4WD to my 87, I made that mistake. It would bind a lot on dry pavement. It would be squirrely in snow. I swapped the transmission with another, and it's normal now. In my case, the 4wd transmission that had the odd ratio was from my 86 carbed 4wd. All of the others I gave are 87 and newer version, and have the same ratio, but different from the 86.

I seriously doubt the improper transmission is the issue since the exact same transmission was used in it for years with no issue previously. The only thing that has been swapped since I got it was the engine, which came out of a 92 loyale FWD. Yes I did swap the flywheel/clutch set off of the original motor as the 4WD and 2WD clutch and flywheel wont interchange. It is in good condition. So theoretically, there should be no issue that wasnt there before it was parked for years. My conclusion was that perhaps the part of the trans that transfers power to the rear is binding since the 2WD works fine and it doesnt want to shift from 4WD to 2WD. The diff and axles must rotate even in 2WD so that eliminates that possibility.

Just to be on the safe side, what is the easiest way to identify the transmission and its corresponding gear ratio? ID stamp?

Get the car jacked up on stands, remove the sump plug from the transmission.

As it's almost directly below the front diff, you can count the number of teeth on the crown wheel.

39 = 3.9:1

37 = 3.7:1

 

Even here, where all of the 5spd 4wd models are dual range, finding a 3.9 ratio gearbox is really difficult. Would be even more so over there where the dual range is rarer.

If the previous people were only ever driving in 4wd on more slippery surfaces, you may not notice the differing ratios front to rear, except that it'd drive a bit strange, which could be thought to be other stuff like old age or worn out...

The 3.7 vs 3.9 mismatch is hard to miss. I drove mine with that for a while before I had time to swap in the correct transmission.

 

Are the 4 tires the same model and wear? That can make drag also, but not as bad as the gear ratio miss match.

That may be the case. All the tires are old and a couple were mismatched. I did move them around so the front 2 match and the rear 2 match but I will be replacing all 4. Thanks for the help everyone.

I've ocasionally ended up with odd pairs of tires. I ran them during non snowy months mostly, switch the 4wd on momentarily if I wanted extra traction on rain for a quick start, then right back off. An advantage of switchable 4wd over awd. But it's definitely better to have all 4 the same.

It is better to have the mismatches on opposite ends, if you can get them set up just right.  With big tires on one end, and small ones on the other, there is guaranteed to be problems in the middle.  There are differentials at the ends to take care of mismatch, but not in the middle.

the differential locking has absolutely no bearing when driving straight, i've driven quite a few Subaru's with the diff/4WD locked and they exhibit zero issues driving straight.  so the 4WD controls (solenoids, vacuum hoses, vacuum diaphragm) shouldn't be the issue. 

 

I'm pretty sure this leaves the tires and mismatched differential ratios.

 

if you have two "larger" sized tires - install one on the front left and one on the rear right.   (or front right and rear left).   that might alleviate tire related issues. don't do that if you have a rear LSD though.  and check inflation pressure.  or just install 4 tires that are more closely matched. 

 

sounds like it's not the diffs from your end, it's hard to diagnose and help over the internet with cars we know nothing about so just aiming for clarity here.  if the diffs were different ratios, it would not be hard to drive it years in FWD with variety of reasons making 4WD unnoticed. 

Were any Loyales available with dual range or did they just get push button?

get all the tire size matching if they are not. diameter differences will give you a major bind, and major wear on the differential and transmission. they are engineered to allow a maximum difference in height between tires. if the diff or tires are mismatched, it means the tires are spinning opposite speeds. that causes binding if say the fronts are spinning 20mph and the rear are spinning slower or faster.

Edited January 21, 20179 yr by 87subbomber