View Full Version : What's up with my car?

11-29-2004, 05:38 AM
I've seen almost everyone state that their cars run a lot lower rpms at highway speeds than my car does. my car is usually no less than 2000 rpms at highway speed, maybe a little lower if I coast.
now I know gears would make your rpms higher, but I don't HAVE gears. still a stock, open diff. the only thing I have changed on the drivetrain is the tranny.
I got the tranny from the previous owner. the one on the car had od burned out, and he had this rebuilt one lyin around that he never put it. so i ended up putting it in in my driveway. one thing that I had to do in order to get it all in there was shorten the driveshaft, cuz the tail of the tranny was too long. my uncle said it was because it was probably from a floor shift-equipped car. the arm that the shifting linkage connects to points up, does that mean it's from a floor-shift car?
and even if it was, could it possibly cause my rpms to be higher than normal? it shifts into OD at 46mph, no less.
also, I installed a B&M shift kit when I installed the tranny. could this cause it?
if I ever put gears in my car, my rpms @ highway speeds would probably be like 3000 rpm :disappoin


11-29-2004, 05:38 AM
oh it's an AOD in an 88 Tbird 5.0

11-29-2004, 07:56 PM
two grand's a little high at od cruise speed imho.

might just be the B&M kit.

get this,,but the opposite, my wife had an e4od tranny in this 7000 pound bronco. In OD, it ran a whole 1700 rpm.

does it shift twice or three times?

11-30-2004, 01:14 AM
yeah it's high, that's y i'm like "WTF?!"
it shifts into OD, this I know for sure, no doubt about it. someone else insisted that it was just the lockup engaging, but believe me, you KNOW when it shifts. are there like different ratios in different AODs or somethin?

11-30-2004, 09:04 PM
are you running a stock tire size? if you went from 215/70/14 to 215/60/14 or some such that would do it

11-30-2004, 11:14 PM
205/65/15, i think from the tires that were on it 205/75/14, if i remember right it's too small of a difference to do anything, much less make a 500+rpm difference at highway speeds

11-30-2004, 11:41 PM
I didn't bother bringing that up as your speedometer would be reporting really high numbers at the same time

12-01-2004, 01:59 AM
yeah, I'm not going too fast, my engine is :dunno:


12-01-2004, 02:40 AM
Could it have the wrong number of speedo drive gear teeth on the tailshaft?

12-01-2004, 04:09 AM
but it isn't the speedo that's the prob, it's my engine rpms. speed is fine, I used the same speedo drive as the AOD that I swapped out

hell, I'm entertaining the idea that someone put better gears in there or SOMETHING, cuz somethin just isn't right. anyone else use a B&M shift kit and have this happen?

12-04-2004, 04:18 AM
If it started life with an 8-tooth drive gear, & the new trans has a 7-tooth drive gear, you'll be going faster than the speedo says you are, by about 14%. That would make your engine go from 1800 to 2052rpm at the same indicated speed.

12-04-2004, 10:47 PM
no, it cant be off that much cuz when i get speeding tickets i'm going the ticketed speed, and I stay with traffic at the same speed they are

it's also more than 200rpm. at 65 i'm at about 2200, 75mph, aboput 2600.