I have a 1987 SR5 and it was originally an automatic but the people before me converted it to a manual. I was wondering if the sr5 automatic rear end is strong enough to handle the power of the 4age.
Thank you

The SR5 rear axle is more the adequate for a stock 4AGE. The SR-5 axle [S series 6.38 ring gear] will have a 3.9 ratio or a 4.10 axle ratio. The axle is probably the 4.10 since the original car was an automatic. This ratio, actually better suits the power band of the 4AGE engine. Dave W

I was hearing that sr5 rear ends were breaking under the 4ac motor so I was wondering if the 4age would be too much. Thank you for clearing it up

Drifting, clutch kicks, welded diff, burnouts, etc. will easily roast an sr5 rear, even a gts rear...

davew7 wrote:The SR5 rear axle is more the adequate for a stock 4AGE. The SR-5 axle [S series 6.38 ring gear] will have a 3.9 ratio or a 4.10 axle ratio. The axle is probably the 4.10 since the original car was an automatic. This ratio, actually better suits the power band of the 4AGE engine. Dave W

i completely disagree, 4.7-4.9 exploit the performance potential of the 4ag, 4.3 is a good medium best of both world reason why most gts's came stock with that drive, and 4.1-3.9 is great for long distance highway driving but suck for motorsport if using a 4ag, u need a more powerful engine for that gear...but an sr5 rear can easily hack the power from a 4ag, especially from an automatic rear, that rear has probably seen very little abuse lol

arvin429 wrote:I have a 1987 SR5 and it was originally an automatic but the people before me converted it to a manual. I was wondering if the sr5 automatic rear end is strong enough to handle the power of the 4age.
Thank you

Deuce Cam wrote:Drifting, clutch kicks, welded diff, burnouts, etc. will easily roast an sr5 rear, even a gts rear...

I don't know the specific differences between the SR5 and GTS rear end well enough to give you a direct answer, but I would argue that maintenance and abuse will be the deciding factor if if the rear end will hold up.

Regardless if its an LSD thick rear end or skinny open diff thing if you abuse it and ignore it, then it won't hold up.

Thats what I'm dealing with right now with my LSD rear end. Previous owner took good care of the vehicle but neglected the rear end so its noisy as sh*t

xslowpokex wrote:

davew7 wrote:The SR5 rear axle is more the adequate for a stock 4AGE. The SR-5 axle [S series 6.38 ring gear] will have a 3.9 ratio or a 4.10 axle ratio. The axle is probably the 4.10 since the original car was an automatic. This ratio, actually better suits the power band of the 4AGE engine. Dave W

i completely disagree, 4.7-4.9 exploit the performance potential of the 4ag, 4.3 is a good medium best of both world reason why most gts's came stock with that drive, and 4.1-3.9 is great for long distance highway driving but suck for motorsport if using a 4ag, u need a more powerful engine for that gear...but an sr5 rear can easily hack the power from a 4ag, especially from an automatic rear, that rear has probably seen very little abuse lol

I read Dave's post as meaning "of the two ratios for the SR5, the 4.10 from an automatic better suits the powerband of a 4AGE than the 3.9". The original poster is asking about the existing axles and diff that he already owns, not overall-best-in-the-world.

That being said, 4.778:1 is a rocking rear for the 4AGE, for autoX and track days, but really sucks on long drives, unless you love to keep the tach at 5k+ (depending on what your speed limit is, and how much you exceed it....). I think it's probably just fine in city driving also, but since it only takes about two minutes for me to be NOT in a city, I can't give a definitive objective report.

All im saying is the Sr5 rear will hold up no probelm, but dont expect a dramatic performance gain from a 4ag vs a 4ac with a 4.1 or even less 3.9 final drive. Honestly, the 4ag is only producing about 20 more hp and 15ft-lbs of torque more than a 4ac, probably a solid strong 4ac makes about the same power vs a non rebuilt high revved 4ag haha, but here is where the right gear for the need is crucial, if u wanna take advantage of the high reving 4ag capabilies and have a fun, snappy, high reving, slide happy 86 you need a 4.7 or higher final drive, and 4.3 for a sporty cruisable, week end slider with smaller rims and tires, anything higher than 4.3 just feel like a pickup truck haha...when i had my 4.7 rear gts coupe with a pretty tired old engine, a buddy with freshly swapped Blacktop 20v in his sr5 was very dissappointed in his own carwhen he drove mine, he claimed my car felt faster, more responsive, and overall sportier and fun than his, but it was all in the final drive and tire size that held his engine back after he swapped a gts rear witn a 4.3 final drive his car came more alive he said....

Well, these two swapped a Lexus V8 into an otherwise legit stock AE86 SR5.............. as in stock SR5 rear end.

http://www.superstreetonline.com/featur ... gine-swap/

There was once a r&p 4.3:1 and 1.5 clutch type lsd set available for these 6.38 SR5 rear end from TRD

Gino1X1 wrote:Well, these two swapped a Lexus V8 into an otherwise legit stock AE86 SR5.............. as in stock SR5 rear end.

http://www.superstreetonline.com/featur ... gine-swap/

There was once a r&p 4.3:1 and 1.5 clutch type lsd set available for these 6.38 SR5 rear end from TRD

Sowwy, the article does state that it has the 6.7 GTS rear end. Mah badd.