Th 400 in a 1998 Trans Am
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TECH Apprentice
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From: Huffman, Texas
Th 400 in a 1998 Trans Am Does anyone know the conversion formula that is needed to make the speedometer work in a 1998 car? I attached the VSS to the drivers side TC sensor.
I found the other conversions but not for a 1998
I found the other conversions but not for a 1998
FormerVendor
Joined: Oct 2006
Posts: 3,123
Likes: 3
From: D-F/W
https://ls1tech.com/forums/automatic...350-th400.html
Check out that thread and let me know if you need anything else... if you didn't know, there is a wealth of knowledge in the stickies at the top of this forum. Good stuff there for guys like yourself that are always thrashing something for clients and other folks.
Let me know if you need anything Chad. I got your back.
g
Check out that thread and let me know if you need anything else... if you didn't know, there is a wealth of knowledge in the stickies at the top of this forum. Good stuff there for guys like yourself that are always thrashing something for clients and other folks.
Let me know if you need anything Chad. I got your back.
g
Thread Starter
TECH Apprentice
iTrader: (94)
Joined: Oct 2005
Posts: 300
Likes: 0
From: Huffman, Texas
https://ls1tech.com/forums/automatic...350-th400.html
Check out that thread and let me know if you need anything else... if you didn't know, there is a wealth of knowledge in the stickies at the top of this forum. Good stuff there for guys like yourself that are always thrashing something for clients and other folks.
Let me know if you need anything Chad. I got your back.
g
Check out that thread and let me know if you need anything else... if you didn't know, there is a wealth of knowledge in the stickies at the top of this forum. Good stuff there for guys like yourself that are always thrashing something for clients and other folks.
Let me know if you need anything Chad. I got your back.
g
Unless I'm reading it wrong...
Last edited by Bad Chad; Sep 19, 2011 at 05:45 PM.
You can get a factory VSS for the th400s. I think it costs a couple hundred (if buying new parts). Otherwise, scour the junkyards for the tailshaft/reluctor/VSS/pigtail/etc off of a 91 chevy diesel.
FormerVendor
Joined: Oct 2006
Posts: 3,123
Likes: 3
From: D-F/W
My apologies, you're right. The 98 PCM does not let you go more than 22k or so per mile.
Let me make some calls in the morning and I'll get back to you... pm me your number and I'll give you a shout with what I find. I believe that you'll need to go to a setup like slow67 mentioned. Meaning, an output shaft that will accept a reluctor, a tailhousing to accept a late inductive sensor and a 40 tooth tone wheel on the shaft.
Hit me with your number and I'll get you the info you need.
g
Let me make some calls in the morning and I'll get back to you... pm me your number and I'll give you a shout with what I find. I believe that you'll need to go to a setup like slow67 mentioned. Meaning, an output shaft that will accept a reluctor, a tailhousing to accept a late inductive sensor and a 40 tooth tone wheel on the shaft.
Hit me with your number and I'll get you the info you need.
g
This is how I have done it in HP tuners and works everytime.
Works for 6-speed swap to TH400
1st input the tires size and gear ratio and let hp tuners calculate.
2nd take 40 and divide it by 17 to receive 2.35 and multiply 2.35 by your general vss pulses per mile.
3rd take that number and manually input that number in the general vss pulses per mile.
4th save everything and take it for a spin. This only works if the th400 is hooked up electronically to the factory speedometer wiring on the t56 or a4.
So for instance you would say, I have 29" tires with 3.42 gears I will commit in HPtuners. The general vss pulses per mile will become 95352. If you PCM is flashed with for a t56 I believe the revs-trans will be at 17. The TH400 revs-trans is 40 so you need to take 40 and divide it by 17 which equals 2.35. So multiply 95352 by 2.35 to equal 224357.63. Now take 224357.63 and manually input 224357 into the general vss pulses per mile. Save your data and load your tune to the PCM. Take it out for a spin. See if the speedometer works. I have only done this on a T56 swap to TH400 car. We got all the correct wiring to hook the speedometer up to the factory speedometer plug for the t56.
I hope this helps you out. If you not getting it to work. I can help you out by you giving me some basic info like tire size, gear ratio and th400 swap info. Good luck
Works for 6-speed swap to TH400
1st input the tires size and gear ratio and let hp tuners calculate.
2nd take 40 and divide it by 17 to receive 2.35 and multiply 2.35 by your general vss pulses per mile.
3rd take that number and manually input that number in the general vss pulses per mile.
4th save everything and take it for a spin. This only works if the th400 is hooked up electronically to the factory speedometer wiring on the t56 or a4.
So for instance you would say, I have 29" tires with 3.42 gears I will commit in HPtuners. The general vss pulses per mile will become 95352. If you PCM is flashed with for a t56 I believe the revs-trans will be at 17. The TH400 revs-trans is 40 so you need to take 40 and divide it by 17 which equals 2.35. So multiply 95352 by 2.35 to equal 224357.63. Now take 224357.63 and manually input 224357 into the general vss pulses per mile. Save your data and load your tune to the PCM. Take it out for a spin. See if the speedometer works. I have only done this on a T56 swap to TH400 car. We got all the correct wiring to hook the speedometer up to the factory speedometer plug for the t56.
I hope this helps you out. If you not getting it to work. I can help you out by you giving me some basic info like tire size, gear ratio and th400 swap info. Good luck
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Chad, is this the trans you got from me? Doesn't it have a 3 wire sensor on the tail housing? I have this box that might help you out. I am not sure if it will or not. I never hooked it up. Maybe Gilbert or someone else will know if it will work for you.
http://www.dakotadigital.com/index.c...rod/prd126.htm
http://www.dakotadigital.com/index.c...rod/prd126.htm
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From: Huffman, Texas
My apologies, you're right. The 98 PCM does not let you go more than 22k or so per mile.
Let me make some calls in the morning and I'll get back to you... pm me your number and I'll give you a shout with what I find. I believe that you'll need to go to a setup like slow67 mentioned. Meaning, an output shaft that will accept a reluctor, a tailhousing to accept a late inductive sensor and a 40 tooth tone wheel on the shaft.
Hit me with your number and I'll get you the info you need.
g
Let me make some calls in the morning and I'll get back to you... pm me your number and I'll give you a shout with what I find. I believe that you'll need to go to a setup like slow67 mentioned. Meaning, an output shaft that will accept a reluctor, a tailhousing to accept a late inductive sensor and a 40 tooth tone wheel on the shaft.
Hit me with your number and I'll get you the info you need.
g
This is how I have done it in HP tuners and works everytime.
Works for 6-speed swap to TH400
1st input the tires size and gear ratio and let hp tuners calculate.
2nd take 40 and divide it by 17 to receive 2.35 and multiply 2.35 by your general vss pulses per mile.
3rd take that number and manually input that number in the general vss pulses per mile.
4th save everything and take it for a spin. This only works if the th400 is hooked up electronically to the factory speedometer wiring on the t56 or a4.
So for instance you would say, I have 29" tires with 3.42 gears I will commit in HPtuners. The general vss pulses per mile will become 95352. If you PCM is flashed with for a t56 I believe the revs-trans will be at 17. The TH400 revs-trans is 40 so you need to take 40 and divide it by 17 which equals 2.35. So multiply 95352 by 2.35 to equal 224357.63. Now take 224357.63 and manually input 224357 into the general vss pulses per mile. Save your data and load your tune to the PCM. Take it out for a spin. See if the speedometer works. I have only done this on a T56 swap to TH400 car. We got all the correct wiring to hook the speedometer up to the factory speedometer plug for the t56.
I hope this helps you out. If you not getting it to work. I can help you out by you giving me some basic info like tire size, gear ratio and th400 swap info. Good luck
Works for 6-speed swap to TH400
1st input the tires size and gear ratio and let hp tuners calculate.
2nd take 40 and divide it by 17 to receive 2.35 and multiply 2.35 by your general vss pulses per mile.
3rd take that number and manually input that number in the general vss pulses per mile.
4th save everything and take it for a spin. This only works if the th400 is hooked up electronically to the factory speedometer wiring on the t56 or a4.
So for instance you would say, I have 29" tires with 3.42 gears I will commit in HPtuners. The general vss pulses per mile will become 95352. If you PCM is flashed with for a t56 I believe the revs-trans will be at 17. The TH400 revs-trans is 40 so you need to take 40 and divide it by 17 which equals 2.35. So multiply 95352 by 2.35 to equal 224357.63. Now take 224357.63 and manually input 224357 into the general vss pulses per mile. Save your data and load your tune to the PCM. Take it out for a spin. See if the speedometer works. I have only done this on a T56 swap to TH400 car. We got all the correct wiring to hook the speedometer up to the factory speedometer plug for the t56.
I hope this helps you out. If you not getting it to work. I can help you out by you giving me some basic info like tire size, gear ratio and th400 swap info. Good luck
Chad, is this the trans you got from me? Doesn't it have a 3 wire sensor on the tail housing? I have this box that might help you out. I am not sure if it will or not. I never hooked it up. Maybe Gilbert or someone else will know if it will work for you.
http://www.dakotadigital.com/index.c...rod/prd126.htm
http://www.dakotadigital.com/index.c...rod/prd126.htm
My cell is 281-701-1909 I'm in and out of meeting all day so leave a message if I do not answer
This is on an A4 car
Yes, it is on the same transmission. I tried to find an wiring diagram for the speed sensor that is in the transmission. I decided to just do the free speedometer mod but with the car being an 1998 I need to figure out the formula or find the wiring diagram for the sensor.
This is on an A4 car
Yes, it is on the same transmission. I tried to find an wiring diagram for the speed sensor that is in the transmission. I decided to just do the free speedometer mod but with the car being an 1998 I need to figure out the formula or find the wiring diagram for the sensor.
Thread Starter
TECH Apprentice
iTrader: (94)
Joined: Oct 2005
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From: Huffman, Texas
Glad to hear. I would be afraid of it too. Spray it off the brake and watch the carrier fall out of the housing. I am working on the 80 swap still. I don't have much free time as of lately so its not moving as fast as I would like it to, but oh well, it will get there.
