4bt T400 transmission Torque convertor question
4BTSwaps.com is the premier Cummins Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 13 of 13

Thread: 4bt T400 transmission Torque convertor question

  1. #1
    Supporting Member brobrad's Avatar
    Join Date
    Sep 2011
    Location
    Moselle Mississippi
    Posts
    986
    Thanks
    21
    Thanked 16 Times in 16 Posts

    Default 4bt T400 transmission Torque convertor question

    I have a 2002 4bta with a t400 behind it. I have looked at putting the engine a few different trucks and run into walls (financially) in several different directions. I understand that to mate the 4bt to a gas tranny you need to do some upgrades for top end speed and torque reasons. My question is has this already been done to the t400 behind it in the chevy step van???

  2. Remove Advertisements
    4BTSwaps.com
    Advertisements
     

  3. #2
    Registered User
    Join Date
    Feb 2007
    Location
    So-central Kommifornia
    Posts
    3,391
    Thanks
    156
    Thanked 158 Times in 120 Posts

    Default

    The main reason Frito Lay decided to pull all the Cummins 4BT out & stick in gassers again is because 4BT's eat GM auto tranny's like a bag of Jalapeno chips. Even the built Pontiac TH465 was just a snack, my step van was on the 3rd one of those. Dodge trans & some Ford trans are proven to work, also other choices in GM will work, but I'm not a GM guy so can't say which.
    Please, READ STICKIES at top of forum sections!

    1967 Dodge Town Wagon now D-200+ - CPL 858 - HTT Stage II/H1C 16cm2 Ex/58mm Comp wheel, no W/G, turned fuel pin, twisted screws, 3,200 spring, milled head, '92-'93 CTD intercooler [THANKS BILL!!!] Dodge NV4500, 4.10 DANA 60HD rear, '72 Dodge D-200 front axle, 1 ton+ springs, Air-Lift front airbags, front/rear swaybars, Tom Wood's driveshaft, Hercules All Trac A/T in LT 245/75-16.

  4. #3
    Supporting Member brobrad's Avatar
    Join Date
    Sep 2011
    Location
    Moselle Mississippi
    Posts
    986
    Thanks
    21
    Thanked 16 Times in 16 Posts

    Default

    Quote Originally Posted by JimmieD View Post
    The main reason Frito Lay decided to pull all the Cummins 4BT out & stick in gassers again is because 4BT's eat GM auto tranny's like a bag of Jalapeno chips. Even the built Pontiac TH465 was just a snack, my step van was on the 3rd one of those. Dodge trans & some Ford trans are proven to work, also other choices in GM will work, but I'm not a GM guy so can't say which.
    That is what i am afraid of with this one. I Know there are 69k miles on this engine, and i assume as many are on the tranny. There is one for sale locally that has a "new" t400 behind it. Many the ones for sale on line have bad transmissions (t400's) when they are sold. I'm really not in a situation to purchase another transmission. I have an 89 f250 with a 4 speed on the floor, but by the time i buy a ford adapter etc. it's just crazy. I may just have to stick the t400 in one of the candidates i have to choose from and see how long it will last. I am told by the folks in the "know" that one should beef up any tranny to get the right speed and torque capabilities, but the budget is quite slim right now.

  5. #4
    Registered User
    Join Date
    May 2008
    Location
    SW Virginia
    Posts
    117
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default

    The TH-400 is a very good transmission, and usually said to be in the same "bullet-proof" ballpark as the Torquelight 727 and Ford's C6.

    The problem was plain and simple, for commercial stop & go driving, in a 8000lb gross stepvan, the TH-400 was slightly too small, that is why the Allison tranny survives much better. It's just a WAY heavier duty unit. So think about what you are putting your combo into and what type or driving you want to do. The 4BTA + TH-400 will last FOREVER in a Jeep CJ sized chassis.
    2001 Classic Roadsters Badlands - H1 Hummer Kit
    77 GM 3/4 ton 4x4 chassis, 3.73 gears, TH350, NP203, 35" tires
    chip truck 4bt w/ TH400 (picked up 7/08)

  6. #5
    Supporting Member brobrad's Avatar
    Join Date
    Sep 2011
    Location
    Moselle Mississippi
    Posts
    986
    Thanks
    21
    Thanked 16 Times in 16 Posts

    Default

    Quote Originally Posted by dsuds View Post
    The TH-400 is a very good transmission, and usually said to be in the same "bullet-proof" ballpark as the Torquelight 727 and Ford's C6.

    The problem was plain and simple, for commercial stop & go driving, in a 8000lb gross stepvan, the TH-400 was slightly too small, that is why the Allison tranny survives much better. It's just a WAY heavier duty unit. So think about what you are putting your combo into and what type or driving you want to do. The 4BTA + TH-400 will last FOREVER in a Jeep CJ sized chassis.
    That's kinda my thoughts on it. If i get a few thousand miles out of it, i can upgrade to another tranny when she goes. I do see the major dilemma being the huge step van loaded to the hilt with the stop and go of a delivery van being the real issue. Thanks for the help.

  7. #6
    Registered User
    Join Date
    Feb 2007
    Location
    So-central Kommifornia
    Posts
    3,391
    Thanks
    156
    Thanked 158 Times in 120 Posts

    Default

    Quote Originally Posted by brobrad View Post
    That's kinda my thoughts on it. If i get a few thousand miles out of it, i can upgrade to another tranny when she goes. I do see the major dilemma being the huge step van loaded to the hilt with the stop and go of a delivery van being the real issue. Thanks for the help.
    I know zip about GM slush boxes. But, from even the 6BT sites the problems that seemed to crop up with many were torque converter failures. Built TC is cheaper than a tranny maybe, but I dunno.

    Second, the absolute #1 Enemy of automatic's is HEAT! That's what whacks them quickest & hardest. Even B&M's largest tranny cooler is comparatively cheap so if it were me....

    That and stick a temp gauge in for tranny fluid on pressure side, more cheap insurance. Clean fluid & filter with fat tranny cooler in a fairly light rig & not pounding the daylights out of it, just might work fine. Lower gears reduces load too. Terrain plays a part, steep mountains or heavy load at low speed being the worst scenario.
    Please, READ STICKIES at top of forum sections!

    1967 Dodge Town Wagon now D-200+ - CPL 858 - HTT Stage II/H1C 16cm2 Ex/58mm Comp wheel, no W/G, turned fuel pin, twisted screws, 3,200 spring, milled head, '92-'93 CTD intercooler [THANKS BILL!!!] Dodge NV4500, 4.10 DANA 60HD rear, '72 Dodge D-200 front axle, 1 ton+ springs, Air-Lift front airbags, front/rear swaybars, Tom Wood's driveshaft, Hercules All Trac A/T in LT 245/75-16.

  8. #7
    New Registered User
    Join Date
    Nov 2011
    Location
    Cranbury, NJ
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default

    Brobrad, where did you find a Torque converter and flex plate to fit the th400? or did it come already together. I have been trying to find a TC and Flex plate that will fit 6bt-TH400 and have had no luck. Any ideas?

  9. #8
    Supporting Member brobrad's Avatar
    Join Date
    Sep 2011
    Location
    Moselle Mississippi
    Posts
    986
    Thanks
    21
    Thanked 16 Times in 16 Posts

    Default TH 400 torque convertor flex plate

    I believe there is a set up on ebay and i also think there are some in the classified adds on this sight. It is terribly slow and i could not reply with quote for some reason. Mine came as a unit in the frito lay van i bought. HOWEVER, the th400 will not stand up behind the 6bt. They are known to split down the side even from the 4bt. Many of the step vans you see for sale have a bad tranny due to 4bt torque. The 6bt will eat the th400. I would suggest finding a dodge tranny that already has everything for the 6bt. You can get an adapter and go with one of the allison 1000 series. An older 01 or 02 is around 1200. You'll need another 1600 for controller and adapter plus the flex plate. I'm not an expert, but have read a lot on this site. I've decided to stay with my Dodge 518 with OD with my 6bt.

  10. #9
    New Registered User
    Join Date
    Oct 2011
    Location
    cameron nc
    Posts
    9
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default Turbo 400 6bt twin turbo

    I have an 86 chevy crew cab 1 ton, 6bt with a turbo 400. I had a Riverside Engines pulling truck 6bt in it about a year ago -twin turbos and all the goodies around 800hp and a destroked adapter to the TH400. it works excellent But it was built by Freddie Brown in NY and has a awesome torque converter-probably by Precision? full manual shift and reverse pattern. the th400 is a great trans and can take the punishment if set up correctly.

  11. #10
    Supporting Member brobrad's Avatar
    Join Date
    Sep 2011
    Location
    Moselle Mississippi
    Posts
    986
    Thanks
    21
    Thanked 16 Times in 16 Posts

    Default TH400 Good Tranny

    Thanks Rodge for the input. I know that the TH400 CAN be built to handle the torque, but most are not. I should have expressed that the stock TH400 for a gasser would not last behind the 6bt. I have talked a few folks about the one in the Frito-lay van and i have been assured that the torque convertor and transmission components were designed to hold up under the load. This will be especially true for mine since i will be going from a loaded P-30 to a 91 F150 for mine.

    While we are here, i noticed a larger bolt pattern on the back of the GM adapter. Any idea what OD GM transmissions might bolt to this adapter?

  12. #11
    New Registered User
    Join Date
    Oct 2011
    Location
    cameron nc
    Posts
    9
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default th400

    I have had several different 4bt/6bt adapters. some had both buick-olds-pontiac and chevy bolt patterns( bop and chevy use the same lower holes) while other adapters just had the chevy 6 bolt pattern. overdrives in automatics will probably be limited to the 4l80 or 4l80e. as the cummins would most likely eat a 700r4 or 4l60/e. i run the gear vendors in the 86 crew cab with 4.56 and 33" 19.5 tires for about 65 mph. hard to get everything in 1 package sometimes.

  13. #12
    New Registered User
    Join Date
    Nov 2011
    Location
    Cranbury, NJ
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default

    Rodgera, or anyone for that matter do you have a flaxplate or torque converter that you would be willing to sell. I already own the adapter plate. Thanks

  14. #13
    New Registered User
    Join Date
    Oct 2011
    Location
    cameron nc
    Posts
    9
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default

    only an allison 545 to 4bt/6bt flywheel at the moment- several th400/th475 transmissions with the full pan also here. i do have t/c 's out of 4bt bread trucks.

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts