i think its my transmission.

FLATACID · 11-03-2001, 08:04 PM

i think my transmision is going to go out on me. i noticed 2 things that where different yesterday. 1. when i would put my cruise control on in 5th, it would start to accelarate, then let off, then start again. it would do that about 5 times. 2. when my speedo was doing 80 in 5th, my rpms would be at 2000. i have 3.08's and there usally at 2150 at 70. to me this sounds like the transmision is spinning faster than normal. i did just put some 16 inch ponys on the back but i wouldn't think that would make a difference. it feels notchier than normal and i just feels roughier than normal. any suggestions would help.

------------------
mods:
dumped ultra flo's, moroso air intake, frpp underdrive pulleys, florida 5.0 guages, 3g alt

Mr 5 0 · 11-03-2001, 08:45 PM

Help us out with more info;

What year Mustang? (I assume it's a 5.0).

Is it an AOD or T-5 (manual).

Did you go from 15" wheels to 16"?

The cruise control glitches could well be electrical and have nothing to do with the transmission.

Going to 16" wheels from 15" would change the RPM's (downward) at a given speed.

If it's a manual (T-5), the clutch could be slipping at higher RPM's. If an AOD, the fifth gear band may be going out.

Either way, change the transmission fluid immediately and see what happens; I strongly recommend synthetic trans fluid.

Unit 5302 · 11-04-2001, 05:01 PM

Quote:

Originally posted by Mr 5 0:
Help us out with more info;
If an AOD, the fifth gear band may be going out.

Damn those 5th gear bands in that AOD!!! I bet those extra gears that were errantly installed in that tranny cause more failures than everything else combined.

Sorry, I couldn't resist. If you have a 5th gear, you've got a T-5, and the problems you are bringing up here are not transmission related.

The wrong sized tire can make quite a little impact, so that could certainly be causing part of the speed issue. More likely it's just a vacuum leak in the cruise control system. Mr 5.0 is right though, we could use a little more information.

macx · 11-06-2001, 12:52 AM

You can do a quick check on your speedo and/or difference in speed due to tires/wheels size change: to find mph per 1000 rpm in direct, multiply rolling tire diameter x 2.975 then divide that by rear ratio. For od, either divide your answer by the od ratio, OR multiple the rear ratio by the od ratio before you divide.

PKRWUD · 11-06-2001, 07:38 AM

Reminds me (very little) of a customer I had once. He had a newer F150, and came in complaining that his cruise control never worked at night. He said it worked fine during the day, but as soon as it got dark outside, it wouldn't work. That's all I had to go on. I checked everything, and went on several test drives, and everything worked fine for me. I talked him into leaving it overnight so I could test drive it in the dark, and it worked fine for me then, too. I returned it to him telling him I could find nothing wrong, and off he went. He returned the next day, saying the problem was still there. I asked him to come by that evening so that he could show me the problem occuring. We went for a drive, and sure enough, the cruise control wouldn't work. I noticed, though, that when he turned on the headlights, he also turned on some fog lights that he had added. I asked him to turn the fog lights off, and try again, and the cruise control worked fine. He dropped off the truck the next day, and I fixed it for him.

What had happened was that when he installed the fog lights, he wired the power for them into the brake light circuit. Every time he turned them on, the body computer noticed the demand in the brake light circuit, and mistook that as him applying the brakes, which always turns off the cruise control. I rewired the power supply to the fog lights, and all was fine.

I know this has nothing to do with this post, but it's a good FYI.

Take care,
-Chris

------------------
Retired Moderator
MustangNet

My site: Peckerwoods Pit Stop

My teams site: Jim Porter Racing

RACECAR spelled backwards is RACECAR

HEY !!! Are you ASE Certified ??? If you are, ask me about iATN.

Coupe5oh · 11-06-2001, 08:43 AM

you'll know when your t-5 is going out, a whineing noise, a cluster shaft can make awful noises like "clicking" "clanking" "grinding"...good luck.

Mr 5 0 · 11-06-2001, 11:28 AM

Unit:

O.K., ya got me. Nothing more embarrassing than mistating facts on a tech page but with well over 4,000 posts, it happens. Mea culpa.

As you correctly pointed out, the mention of 5th gear makes the trans a T-5 and of course AOD's do not have a fifth gear.

I still don't think this is a tranny problem.

[This message has been edited by Mr 5 0 (edited 11-06-2001).]

11-03-2001, 08:04 PM	#1
FLATACID Registered Member Join Date: Nov 2001 Location: Walnut Creek, CA Posts: 5	i think its my transmission. i think my transmision is going to go out on me. i noticed 2 things that where different yesterday. 1. when i would put my cruise control on in 5th, it would start to accelarate, then let off, then start again. it would do that about 5 times. 2. when my speedo was doing 80 in 5th, my rpms would be at 2000. i have 3.08's and there usally at 2150 at 70. to me this sounds like the transmision is spinning faster than normal. i did just put some 16 inch ponys on the back but i wouldn't think that would make a difference. it feels notchier than normal and i just feels roughier than normal. any suggestions would help. ------------------ mods: dumped ultra flo's, moroso air intake, frpp underdrive pulleys, florida 5.0 guages, 3g alt

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11-03-2001, 08:45 PM	#2
Mr 5 0 Conservative Individualist Join Date: May 1997 Location: Wherever I need to be Posts: 7,487	Help us out with more info; What year Mustang? (I assume it's a 5.0). Is it an AOD or T-5 (manual). Did you go from 15" wheels to 16"? The cruise control glitches could well be electrical and have nothing to do with the transmission. Going to 16" wheels from 15" would change the RPM's (downward) at a given speed. If it's a manual (T-5), the clutch could be slipping at higher RPM's. If an AOD, the fifth gear band may be going out. Either way, change the transmission fluid immediately and see what happens; I strongly recommend synthetic trans fluid.

11-06-2001, 12:52 AM	#4
macx Registered Member Join Date: Oct 1999 Location: Gordonville MO USA Posts: 448	You can do a quick check on your speedo and/or difference in speed due to tires/wheels size change: to find mph per 1000 rpm in direct, multiply rolling tire diameter x 2.975 then divide that by rear ratio. For od, either divide your answer by the od ratio, OR multiple the rear ratio by the od ratio before you divide.

11-06-2001, 07:38 AM	#5
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Reminds me (very little) of a customer I had once. He had a newer F150, and came in complaining that his cruise control never worked at night. He said it worked fine during the day, but as soon as it got dark outside, it wouldn't work. That's all I had to go on. I checked everything, and went on several test drives, and everything worked fine for me. I talked him into leaving it overnight so I could test drive it in the dark, and it worked fine for me then, too. I returned it to him telling him I could find nothing wrong, and off he went. He returned the next day, saying the problem was still there. I asked him to come by that evening so that he could show me the problem occuring. We went for a drive, and sure enough, the cruise control wouldn't work. I noticed, though, that when he turned on the headlights, he also turned on some fog lights that he had added. I asked him to turn the fog lights off, and try again, and the cruise control worked fine. He dropped off the truck the next day, and I fixed it for him. What had happened was that when he installed the fog lights, he wired the power for them into the brake light circuit. Every time he turned them on, the body computer noticed the demand in the brake light circuit, and mistook that as him applying the brakes, which always turns off the cruise control. I rewired the power supply to the fog lights, and all was fine. I know this has nothing to do with this post, but it's a good FYI. Take care, -Chris ------------------ Retired Moderator MustangNet My site: Peckerwoods Pit Stop My teams site: Jim Porter Racing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN.

11-06-2001, 08:43 AM	#6
Coupe5oh Registered Member Join Date: Nov 2001 Location: SanAntonio, Tx Posts: 734	you'll know when your t-5 is going out, a whineing noise, a cluster shaft can make awful noises like "clicking" "clanking" "grinding"...good luck.

11-06-2001, 11:28 AM	#7
Mr 5 0 Conservative Individualist Join Date: May 1997 Location: Wherever I need to be Posts: 7,487	Unit: O.K., ya got me. Nothing more embarrassing than mistating facts on a tech page but with well over 4,000 posts, it happens. Mea culpa. As you correctly pointed out, the mention of 5th gear makes the trans a T-5 and of course AOD's do not have a fifth gear. I still don't think this is a tranny problem. [This message has been edited by Mr 5 0 (edited 11-06-2001).]