GM transmission Adapter?

[Bernhard]

Hey guys, I just got a P-30 step van with a 4BT and a 4spd. for my swap I was thinking of going with a turbo 400 is the adapter the same for manuel and automatic in the chevy application?



Thanks,

Brenden

 

[BCronk]

yes, you will need to find a flex plate though. Some people here dont think the th400 will hold up behind the 4bt. I am not trying to say the th400 will hold for sure but, I am running a th350 behind my 6bt and havent had any problems yet, I have about 15,000 mi on it. what are you putting the 4bt in?

 

[Morse]

Avant Diesel Salvage in Georgia has a complete kit including the adaptor and flywheel. The number is 478-552-1901. . Ask for Jamie. He can set you up. .

 

[DKarvwnaris]

All you need is the flex plate for th e4b. Your bellhousing adapter is the same for both manual and auto.

 

[Steve Graham]

Some people here dont think the th400 will hold up behind the 4bt. ?

The TH400 was the only automatic option with the P30, they have stood up very well for commercial on road usage in a 1 1/2 (ton?) delivery van. The only downfall is the the lack of an OD and top speed is limited to about 55mph.



Steve

 

[LAlessi]

must be referring to me.

i said, and continue to say, the th400 was not "bulletproof" behind a 4bt.



you may run a 6bt and th350 but i highly doubt you have put very many miles off road around 900 to 1000 rpm. thats what will kill an auto, and where the stick shines.



on road vs off road is totally different. all of my conversions have been and continue to be offroad biased.

 

[DKarvwnaris]

The TH400 was the only automatic option with the P30, they have stood up very well for commercial on road usage in a 1 1/2 (ton?) delivery van. The only downfall is the the lack of an OD and top speed is limited to about 55mph.



Steve

In addition to this, few of these applications have ever had a trailer hitch of any sorts put behind them. Personally, if I can't count on the rig to be both a reliable daily driver, capable of towing a trailer when need be, and have the capacity to handle off road use even in moderate use, I can not justify the money, time and patience to repower anything. To do it for a customer and be held accountable for using a GM automatic is out of the question, even if they demand it and sign off that its their problem when it falls on its face. I will turn down the job and tell them to let me know when they are ready to have me build it to meet my own standards and feel confident to put my name on it. Those here who have done conversions for others and believe in standing behind their work know what I am talking about.

 

[LAlessi]

in case anyone missed it.

cummins has/had a more stiff transmission pan for the th400 as part of the auto repower package.



i know of no such mod for a 700r4 or a th350. other than is app, im not too familiar with anyone else strengthening the th400 CASE.

 

[Matt S]

Does the 4bt have the same bell housing area as a 6bt? Or will an adapter be needed for an NV4500?

 

[Steve Graham]

Does the 4bt have the same bell housing area as a 6bt? Or will an adapter be needed for an NV4500?

I don't understand your first question, bell housing area?



Most 4B's that came from a bread van (Frito-Lay) had a Chevy (GM) transmission adapter. Therefore you will need a bellhousing from a chevy that used a NV4500 or you can buy one from Advance Adapters.



Steve

 

[DKarvwnaris]

Does the 4bt have the same bell housing area as a 6bt? Or will an adapter be needed for an NV4500?

The machined bolt pattern in the actual block is identical to the 6bt block. The adapter plate commonly referred as a bellhousing adapter that is mounted up to the block and connects via the same holes is different. The bellhousing adapter in the 4bt GM van applications is designed for a gm bellhousing. You can mount a nv-4500 to it using a GM small diameter flywheel, clutch and the GM NV-4500 bellhousing out of any light duty GM truck. If you want the higher HP capable 13" flywheel and clutch that the dodge nv-4500 transmission's use, you'll need to remove the GM bellhousing adapter and starter and go with ALL dodge parts from a 6bt.

The only difference between the dodge and GM bellhousing parts is the starters are on opposite sides, and the clutch size. The price of a Cummins to GM flywheel is over $800 new and only available from Cummins or a junkyard, that is reason enough for me to go the dodge setup personally, since the flywheel is cheaper for the dodge and has multi sources since it is a mainstream dodge pickup part.

Hope that clears it up for you.



I wouldn't use an Advanced adapters product for this setup if it was given to me. The parts from Cummins that came on the 4bt are fine, and the Dodge parts are available just about anywhere used. Why bother with a aftermarket part thay you can only get through advanced adapters and have to pay their full price for it. If it fails or cracks for whatever reason, you'll be stuck going back to only them to get another, unlike a dodge setup or the GM.

 

[Matt S]

That's what I was looking for. I was hoping a Dodge transmission (NV4500) would bolt right up. Would it be the same flywheel? That would be ideal.

 

[LAlessi]

... ... ... ... ..... out of any light duty GM truck. If you want the higher HP capable 13" flywheel and clutch that the dodge nv-4500 transmission's use, you'll need to remove the GM bellhousing adapter and starter and go with ALL dodge parts from a 6bt.

The only difference between the dodge and GM bellhousing parts is the starters are on opposite sides, and the clutch size. The price of a Cummins to GM flywheel is over $800 new and only available from Cummins or a junkyard, that is reason enough for me to go the dodge setup personally, since the flywheel is cheaper for the dodge and has multi sources since it is a mainstream dodge pickup part.

Hope that clears it up for you.

from the post above yours, it looks like a dodge flywheel wil work

 

[DKarvwnaris]

That's what I was looking for. I was hoping a Dodge transmission (NV4500) would bolt right up. Would it be the same flywheel? That would be ideal.

You will need to either use all GM parts with GM adapter plates, or all Dodge parts with dodge adapter plates. The flywheels between the GM adapter and the Dodge is completely different. Both in diameter as well as depth. The dodge flywheel is much larger and will not fit into the GM bellhousing adapter.

You can use a GM nv-4500 transmission if you change the input shaft out to the Dodge part #. It is a simple bolt in part, make sure you understand how to install it though. You can plug up the oil lube port if you put too much sealant on the input flange, which will result in the front bearing spinning dry, iresulting in bearing or race failure shortly after.

If you're planning too use Dodge parts, you will have no need for any plates or adapters from the 4bt. Put them up for sale. The flywheel is going for $800 new, used you should be able to get about $400 or so if you find the right idiot to use the smaller clutch. (I wouldn't use the GM clutch in anything larger than a Jeep) Bread trucks are light weight with very little load and they still go through clutches with the 4bt setups, not in any small part due to the "drive it like you stole it" delivery drivers. Anything over stock HP in the 4bt's will be alot for the small flywheel surface to hold up to.