Last post on Aug 29, 2010 at 9:02 PM
You are in the Subaru Forester Maintenance & Repair
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Subaru Forester, Transmission
#127 of 182 Re: Abrupt shifting 4EAT - 2005 Forester X [erics6]
Feb 11, 2008 (12:47 pm)
Well, the car holds gears longer until the transmission fluid is up to temperature. It does this in order to warm up faster. This could result in a more abrupt shift, but it is hard to say whether the car has a problem or not without feeling the abruptness. I have never driven a Subaru that has a silky-smooth, imperceptible shift when the transmision is warm, but I would not call it abrupt either, just noticeable. In cold temperatures, especially below 0F, the shifts are certainly abrupt until it warms up.
#128 of 182 Question about all-wheel drive system???
Feb 14, 2008 (9:07 am)
I am looking to buy a forester. It seem that there are two different a-wheel drive systems. I am not really bias eighter way on auto or stick shift but could someone explain the difference in the auto All-wheel drive and the stick shift all-wheel drive system? Which is better? Thanks in advance.
#129 of 182 Re: Question about all-wheel drive system??? [aceonthebeach3]
Feb 14, 2008 (1:05 pm)
The MT uses a mechanical system while the AT's is computerized. I'm sure someone can post a link to a description of the two but the end result is that both systems do an excellent job of directing power to the wheels that need it. I personally wouldn't use the AWD system as a deciding factor for which model to buy.
#130 of 182 Re: Question about all-wheel drive system??? [p0926]
Feb 14, 2008 (4:02 pm)
thank you for your help. The MT they say uses a locking differental while the AT uses a limited slip differental,I don't think those are the same. anyway thanks for your help, I have never owned a subaru so this is all new to me
#131 of 182 Re: Question about all-wheel drive system??? [aceonthebeach3]
Feb 14, 2008 (4:48 pm)
Subarus don't have locking differentals. In regards to limited slip differentals, a LSD works by varying power from side to side and is not transmission specific.
The biggest difference between the AT and the MT AWD systems is that the MT has a 50/50 (front/rear) power split under normal conditions. Meanwhile, the AT begins with a 80/20 split (rear/front) and adjusts power delivery from there.
Hope this helps
#132 of 182 Re: Question about all-wheel drive system??? [p0926]
Feb 14, 2008 (8:34 pm)
thanks for the help frank. let me read this to you straight from the brochure and you can sort it out for me "2.5x and 2.5xt models equipped with a 5-speed manual tansmission utilize a viscous-type locking center differential and limited slip differential" I am not saying you are wrong but the way they word this is very hard for a new comer, you are probably right. it seems the MT to be more of a true all-wheel drive than the AT... frank have you driven a MT and a AT? I think that under normal driving the power split will not be a big difference but how about when you are in snow or mudd?
#133 of 182 Re: Question about all-wheel drive system??? [aceonthebeach3]
Feb 15, 2008 (10:28 am)
Basically, the viscous coupling acts as the center differential. When the axles spin at different speeds, the fluid-filled coupling heats up and the fluid thickens and locks the axles together temporarily.
The AT uses what they call Auto AWD, basically electronically controlled variable transfer clutches. Simple yet effective.
Here is a cool video - you see a basic Forester X auto having no trouble transferring power from axle to axle, front to rear and rear to front. Note how little wheelspin there is on the Forester:
Both systems are very capable.
The 2009 models adds traction/stability control, so it will only improve.
#134 of 182 Re: Question about all-wheel drive system??? [aceonthebeach3]
Feb 15, 2008 (4:15 pm)
"... could someone explain the difference in the auto All-wheel drive and the stick shift all-wheel drive system?"
Here are some bits and pieces I have picked up about Forester drive trains:
The X Sports model (either manual or auto) and the LL Bean model (comes auto only) have X model drive trains.
All the Forester drive trains have viscous limited slip rear differentials.
The printed catalog lists the drive trains as follows:
Manual X and XT = Continuous AWD:
Viscous locking center differential and limited slip rear differential.
Automatic X = Active AWD:
Electronically controlled variable multiplate transfer clutch and viscous limited slip rear differential.
Automatic XT = VDC (engine management and traction control system) and VTD (Variable Torque Distribution) AWD:
Electronically controlled variable multiplate transfer clutch, planetary center differential, and viscous limited slip rear differential.
If you have the automatic transmission, power in Drive and 3rd is biased 80/20 toward the front. There is 50/50 power distribution front and rear if you place the selector lever in 2nd or 1st. If you have a manual transmission the split is 50/50 in all gears.
If you have Limited Slip Differential (optional in non-X models, standard in XT models), you'll have at least three of four wheels available. If you don't, you could have two wheels of four available, one front and one rear.
No forester in the US has a front LSD unfortunately (apparently only the forester STI ever got one). The nonvdc foresters have a front open diff with a clutch pack in the center of the car to distribute power f-r and either an open rear diff in the X model or viscous limited slip in the rear on XS and XT models. The forester vlsd is very loose though. A US Forester will act the same as any awd or 4wd that has open diffs. A non-Rubicon Jeep Wrangler will do the exact same thing. You will always have at least 2 wheels spinning, and you can drive through the brakes to get power to transfer.
#135 of 182 Re: Question about all-wheel drive system??? [aatherton]
Feb 15, 2008 (6:34 pm)
Another bit of info just copied:
In the non-X models, when there are LSDs, both automatic and manual models use the rear mechanical LSD. The difference comes at the fore/aft transfer case... Automatic goes electronic (the E in 4EAT) and while in 4 or 3 shifter location, varies the ratio from 80/20 to 50/50 based on "sensed need".
When shifter location is in 2 or 1, the 4EAT locks the center differential at 50/50 power distribution.
When shifter location is in 2, the 4EAT locks second gear. First gear can't be accessed while shifter is in 2, so take-offs are in second gear. Sounds stupid on pavement, but in wintry locations, where snow and ice are common, it seems a lot smarter.
Why are 3 and 4 different from 1 and 2? For reasons of economy having power distributed mostly up front makes a lot of gas mileage sense, with power only going to front pair...plus by the time you're in third and fourth gears, you shouldn't be having traction problems (certainly possible with turbo models, but not advisable in normal use...ie, above speed limit). Wonder why the automatic has traditionally gotten better mileage than the manual? ...it's the E in 4EAT.
Feb 15, 2008 (7:23 pm)
thanks everyone for your help. i think the XT trim sounds like it is the best.