Help identify my driveline issue
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Teching In
Joined: Dec 2014
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Thank you project get tag0 for checking out the videos. you are right about the low speed pop, I am going to a buddy's house tonight to borrow a known good rear axle assembly to rule one more thing out. I will also check the angles again while i am working on it. hopefully will have some more info in the next couple of days. my progress is slow with a 2 week old at home.
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Joined: Feb 2007
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From: Raleigh, NC
Not sure if my problem was truly the same as yours, but in my Fox, it would have a violent shake at any speed under WOT, but it drove just fine otherwise. This was actually with the original 88hp 2.3L Lima and T5. For example, it would cruise great at part throttle, I could upshift or downshift at any speed, and so long as it was part throttle it was OK. I could not figure it out, and had already bought the LS1/T56, so I just pulled the 2.3 and T5.
As it turns out, the problem was that the motor mount had broken, and any time I would got WOT, even with the uber lame 88hp, the engine would lift off the k member, drive line angles would become terrible, and eventually the engine would bang back down into place.
I never would have found the broken motor mount (without having pulled the motor out) without actually putting a jack under the engine and lifting. It never occurred to me an 88hp 2.3L would break a motor mount made out of 3/16" steel. It was probably a manufacturing defect in the weld which lasted about 125k miles.
Anyway, something to check.
As it turns out, the problem was that the motor mount had broken, and any time I would got WOT, even with the uber lame 88hp, the engine would lift off the k member, drive line angles would become terrible, and eventually the engine would bang back down into place.
I never would have found the broken motor mount (without having pulled the motor out) without actually putting a jack under the engine and lifting. It never occurred to me an 88hp 2.3L would break a motor mount made out of 3/16" steel. It was probably a manufacturing defect in the weld which lasted about 125k miles.
Anyway, something to check.
Thread Starter
Teching In
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usdmholden - that is a great piece of information, i had thought about changing to the solid motor mounts but read that the upr mounts would not work with the dynatech longtubes that i have. I may go ahead and order a set and modify them as needed. i am just using stock rubber 4.6 mounts that i modified to fit the ls block. I did video the engine on the chassis dyno and strapped the engine down on the drivers side with a ratchet strap just as a backyard way to test. no positive results. that does not mean that i have ruled it out though.
as of now i am getting the axle out of my friends car tonight. will stick it in the car over the next couple of nights to test. will look at upr solid motor mounts and probably get a new set of rear double adjustable shocks to replace my 10 year old lakewood 50-50's
as of now i am getting the axle out of my friends car tonight. will stick it in the car over the next couple of nights to test. will look at upr solid motor mounts and probably get a new set of rear double adjustable shocks to replace my 10 year old lakewood 50-50's
Thread Starter
Teching In
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I was able to rule out any part in the rear axle as a problem, I installed the complete known good axle from a buddy - all of the same symptoms. The low speed pop once the car is nice and hot is there, the second gear vibration is there identical to the last test with my axle.
One thing that I did forget to mention is that if I accidentally don't downshift from 3rd to 2nd and am going slow still in 3rd the trans slams then will accelerate also when I put it in first from neutral or park the trans will not move then slam into first and take off. I don't really care but it may be an indication of something else. thanks guys. will keep working on drive line angles (after i return this axle to the owner).
One thing that I did forget to mention is that if I accidentally don't downshift from 3rd to 2nd and am going slow still in 3rd the trans slams then will accelerate also when I put it in first from neutral or park the trans will not move then slam into first and take off. I don't really care but it may be an indication of something else. thanks guys. will keep working on drive line angles (after i return this axle to the owner).
Thread Starter
Teching In
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I am planning on pulling the trans and getting it checked out. probably have the converter cut open as well. i have to put my axle back in the car and return the other to its owner so that is first priority.
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well plans changed slightly, I found a converter that a buddy had built locally for his project anyway he was not going to be using it for a while so he let me borrow it. it is a 9" bolt together with a mechanical diode. 5k stall. Its in the car i just need to wrap up the installation of my axle and get fluid to replace what i spilled changing the converter.
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Teching In
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well no good news. I put the loaner converter in yesterday and got everything wrapped up tonight. this converter is looser than mine and the vibration is there still. feels worse actually. I can hold it just past about 50% throttle and the issue happens. of course its there from a roll in second gear as well as on the gear change.
new news is that i think i am close to killing some part hope it happens soon. almost sure that it is inside the transmission. now when warm when i shift into first gear the car does not move and as i give it gas around 1500rpm it finally grabs and feels like you got rear ended by a dump truck. also get a nice shutter vibration just like i have at wot on the 1-2 gear change just crusing at low speed.
so i have changed--- rear axle assembly, control arms, driveline angles and pinion angles, driveshaft, converter.
new news is that i think i am close to killing some part hope it happens soon. almost sure that it is inside the transmission. now when warm when i shift into first gear the car does not move and as i give it gas around 1500rpm it finally grabs and feels like you got rear ended by a dump truck. also get a nice shutter vibration just like i have at wot on the 1-2 gear change just crusing at low speed.
so i have changed--- rear axle assembly, control arms, driveline angles and pinion angles, driveshaft, converter.
Thread Starter
Teching In
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I know. Its hard to convey the problem without discribing wheel hop. Which leads everyone to driveline angles. The ride height changed that and having the axle and suspension apart multiple times I just wanted to check and make sure it was all still good. Th400 is on its way out this weekend if I have time for another built unit that was behind my buddys 1200hp monza. I would be broke from buying everything twice if I didnt have good friends that were willing to loan out parts.
I am also going to put my driveshaft in my buddies 6.0 mustang to see if he experiences any issue with it. Basically a triple check.
Thanks guys!
I am also going to put my driveshaft in my buddies 6.0 mustang to see if he experiences any issue with it. Basically a triple check.
Thanks guys!
Thread Starter
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For anyone that happens to come across this thread in the future. The new transmission fixed my issue. As soon as I dropped the fluid it smelled like burned brake pads. I thought finally something that does not look perfect. So that gave me hope I was going in the right direction. Anyway I put my origional precision converter in this teansmission put a spring behind the trans brake solenoid and bolted the pan on. Slap all of it in the car and take it for a test and all is well. So tonight I changed pans and gaskets, checked the fluid out and wrapped up some loose ends and drove it 20 miles. Im so happy I think I will wash it tomorrow! And put the blower back on with the chance of good weather friday night may get to the track. Too bad its a poor track that is 2 hours and 100 dollars in fuel away.
Thread Starter
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I am not sure what the exact problem was, i have not taken the transmission to the shop. It has a bushing in the tailshaft and looks to be in nice condition. Something internally has to be destroyed to leave brunt black sludge in the bottom of the pan.
Andrew
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Not sure what you mean by that but there is about 400 miles on a fresh build. The person that built it must have done something incorrectly. it only operated without issue for about 20 miles. The trans was $2,000 when I bought it.
Last edited by rg913; Jul 24, 2015 at 09:24 AM.
Andrew