Is GM crazy???? - Page 3 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

Reply
 
 
 
Thread Tools Search this Thread
Old 01-01-2005, 09:55 PM   #21
Senior Member
True Car Nut
 
Join Date: Jun 2004
Location: Glendale, AZ
Posts: 3,459
Thanks: 0
Thanked 1 Time in 1 Post
big_news_1 is on a distinguished road
Default

Here is a copy of the email I sent to Andrew Schreck at GM. Hopefully it elicits responses regarding the 4T65'* reliability issues. Let me know what you guys think of this, and tell me what else I failed to mention. I am far, far from being a transmission guy, so if I left something out please tell me. Thanks!

Quote:
Mr. Schreck-

I just got through reading two very interesting articles on the General Motors website. The first article, from which I obtained your contact information, was from August 2004 and described the prominence of the 2-litre Ecotech engine at the Bonneville Salt Flats. The second was about the Hydramatic 4T65 transmission and its use in the GM Racing Pontiac Sunfire. Due to your apparent involvement in the Ecotech racing program (which powers the Sunfire), I am interested in whatever information you may be able to give me about the tranmission used in that project.

I am an active member of the Bonneville Club (www.bonnevilleclub.com), a collection of car enthusiasts who drive Pontiac Bonnevilles and other 3800-powered GM models. As you know, current production Bonnevilles use the 4T65-E and 4T65 HD transmissions, which explains my interest in the Hydramatic project. The club has many members who, including myself, modify our motors to gain extra performance from our cars. The problem many of us run into is the durability of both the 4T60 and 4T65 transmissions. Many times when power numbers exceed 275 or 300 horsepower with the stock drivetrain, transmission reliability issues are encountered. There is much debate about the "weak link" in the drivetrain, and some members conjecture that transmission failure can ultimately be averted with the replacement of the torque converter and differential with higher-strenth aftermarket units. Nobody is quite sure which stock components have sufficient strength to handle high power applications and which ones do not. What we do know is some members have destroyed differentials (often ruining the rest of transmission), and many of us suffer from increasing levels of transmission slip as the years go by.

My request of you is to provide us with some definitive answers. The article about the Hydramatic 4T65 seems to indicate that a stock 4T65 may be able to take a considerably high horsepower and torque input with the substitution of an aftermarket torque converter and limited-slip differential. This would be very refreshing if it is accurate, as the only viable transmission options currently available to us seem to be expensive transmission overhauls. We have never come to a solid conclusion about the reliability of our transmissions, and your expertise will be sure to clear the air on many of the issues.

Thank you for taking the time to read this letter. I look forward to hearing back from you regarding this issue, and I would request that you share whatever you can about the 4T65 and even the 4T60, if possible. If you are not the correct person to address questions about front wheel drive transmissions, I would ask that you please forward this email to a colleague who may be able to shed some light on this topic. I would also like your permission to post your response to my question on the Bonneville Club website. Thanks again, and have a great new year.

-Ben Eichelberger
big_news_1 is offline   Reply With Quote
Old 01-01-2005, 11:16 PM   #22
Senior Member
Posts like a Camaro
 
Join Date: Dec 2004
Location: Mankato MN.
Posts: 1,005
Thanks: 0
Thanked 0 Times in 0 Posts
Midnight Express is on a distinguished road
Default

I think it Looks good Ben very nice job!!
Midnight Express is offline   Reply With Quote
Old 01-02-2005, 01:03 AM   #23
Senior Member
Certified Car Nut
 
Join Date: Oct 2003
Posts: 19,756
Thanks: 0
Thanked 0 Times in 0 Posts
1993 SLE is on a distinguished road
Default

yes a relpy regarding the trans mated to a modded 3800 is something that could be very helpful
1993 SLE is offline   Reply With Quote
Old 01-02-2005, 01:51 AM   #24
Senior Member
True Car Nut
 
Join Date: Feb 2003
Location: Bloomington-Normal, IL 1997 SE
Posts: 3,734
Thanks: 0
Thanked 0 Times in 0 Posts
macho_mike21 is on a distinguished road
Default

very intelligent email. It would be hard not to reply to that.
macho_mike21 is offline   Reply With Quote
Old 01-02-2005, 01:53 AM   #25
Sol
Senior Member
True Car Nut
 
Join Date: Sep 2002
Posts: 8,909
Thanks: 0
Thanked 0 Times in 0 Posts
Sol is on a distinguished road
Default

Very well written letter. I hope to hear some good info from them.
Sol is offline   Reply With Quote
Old 01-02-2005, 02:45 AM   #26
Senior Member
True Car Nut
 
Join Date: May 2003
Location: Holt, MI & Lima, OH
Posts: 3,022
Thanks: 0
Thanked 0 Times in 0 Posts
dbtk2 is on a distinguished road
Default

Quote:
Originally Posted by fantastic88
I didn't know that guys running 12s even still had the 4T65E. Doesn't a smaller pulley, ehaust work, and rockers usually finish them off?
My dad raced his GTP repeatedly (probably 75-100 runs) with his stock 4T65E-HD. Every run he has ever made has been in the 12'*, with the exception of his first 3 runs when he was learning how to drive it, and one run on a later date with street tires on a very slippery track. He ran a best of 12.408 with the stock tranny and never broke the transmission. He broke a halfshaft, and two INTENSE LSD'*, but never the tranny. It also had a Thrasher Shift Kit on medium, and increased line pressure in the PCM. When he had the tranny rebuilt with around 22k or something like that on it, it was still functioning as it should, he just wanted different gears and a different torque convertor, so they built up the tranny with the ZZP heavy duty parts at the same time, but the tranny guy said it was a lot more worn than it should have been with 22k on it. However, the car was modded since it had 300 miles on it, and it was and is ALWAYS driven hard.

My moms SSEi has ~125k on it, is midly modded and has been since it was almost new, and it has the original tranny and its just fine *knock on wood*.

Since they only use those trannys for a few runs, I can imagine that with just heavy duty imput/output shafts, and a different differential that it can easily handle that kinda power.

Shawn
dbtk2 is offline   Reply With Quote
Old 01-02-2005, 03:49 AM   #27
Junior Member
 
Join Date: Jun 2002
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
2000SilverBullet is on a distinguished road
Default

Mine is still going strong.....knock on wood.
For an SSEi, it'* pulling the equivalent of a 12 sec GTP.
2000SilverBullet is offline   Reply With Quote
Old 01-03-2005, 09:55 AM   #28
Senior Member
Posts like a Camaro
 
Join Date: Jan 2004
Posts: 1,166
Thanks: 0
Thanked 1 Time in 1 Post
mkaake is on a distinguished road
Default

Quote:
Originally Posted by macho_mike21
very intelligent email. It would be hard not to reply to that.
being that i work for the general, I'd have to disagree a little bit to that one

while we have lots of car nuts here, that would love to answer those questions, the biggest problem we have with answering something like that is liability.

that said, i figure about a 35% chance you'll get any sort of a meaningful response. 75% that you'll get a response at all.

as for the tranny, it'* really funny, but do you guys realize that the 4t65 is the most reliable tranny that gm offers? according to jd power, in 2004, was by far more reliable than any other gm tranny.

strange.

of course, that it'* reliable at normal power levels doesn't matter too much when you're not at normal power levels, now does it?

good luck getting an answer. if you don't get one, let me know, and i'll go knocking on some doors, and see if I can't find out for you.

<edit>

which RPO do you guys have for your tranny? i count 5 different 4t65'* from the data i'm looking at right now...
mkaake is offline   Reply With Quote
Old 01-03-2005, 06:54 PM   #29
Senior Member
Certified Car Nut
 
Join Date: Jun 2003
Posts: 15,928
Thanks: 0
Thanked 0 Times in 0 Posts
BonneMeMN is on a distinguished road
Default

I doubt you're gonna get an answer. GM won't say there'* a weakness with one of it'* gear boxes, let alone one that'* still in a lot of vehicles.
BonneMeMN is offline   Reply With Quote
Old 01-03-2005, 11:24 PM   #30
Junior Member
 
Join Date: Jun 2002
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
2000SilverBullet is on a distinguished road
Default

Quote:
which RPO do you guys have for your tranny?
RPO codes M15 - with 245 mm torque converter - N/A 3800
MN3 / MN7 - with 258 mm torque converter - */C 3800 . Mine is MN7 for my SSEi 2.93 ratio.
I can only assume that the 3 codes refer to the 3 final gear ratios available 2.86, 2.93 and 3.05
2000SilverBullet is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Mod crazy...how do you do it? Hailey General GM Chat 16 05-29-2003 03:58 PM
Front End Crazy off the line salmanman Performance, Brainstorming & Tuning 5 04-16-2003 12:26 PM
Hi, new to forum, Lots of crazy questions: 4T60-E + L67 LakefxGP96 1992-1999 11 01-30-2003 05:13 PM
Color choice driving me crazy coachmeeks General GM Chat 22 10-02-2002 10:35 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 07:54 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.