ZF5 out of a gasser ok for a diesel?

[GaPchNCrm]

Yeah ok- probably a dumb question .... I'm eyeballing a few trannys as I have a feeling mine is about to be toast. One of the ones I was looking at is a low miles used one out of a gasser, I said in my initial email that it was for a diesel truck and he said " this one is a big block so it will work fine." Of course I don't know the difference so I thought I better ask before I get to looking at stuff that won't work. Thanks in advance for the help!!

 

[6 Nebraska IDIs]

Its a wide ratio, but it works.
Been done here before.

 

[riotwarrior]

Gasser trannys do not bolt up to Diesel engines and Visa Versa. Thats all there is to it.

 

[6xCrew]

But there is a thred here showing that they can be modded to fit. It is not a bolt on by any means though.

Calvin

 

[GaPchNCrm]

Well I feel better- guess it wasn't such a dumb question afterall lol Thanks guys!

 

[GaPchNCrm]

Heck- lets go all out- can a ZF 6 be modified to fit my truck? Probably not- however I was browing ebay and did note this. A ZF6 fits a 99-02 truck, and a ZF5 fits an 87-97 truck. What did the 98 have in it?

 

[93turbo_animal]

there wasn't a 98 with a diesel in it

 

[G. Mann]

I right now, have two ZF 5 speed transmissions setting side by side. One is from a 460 gas engine, the other is from a 6.9 diesel. They are physically the same except for the bell housing bolt pattern and the internal gear ratio.

The gas trans will NOT fit on the diesel and vice versa.
The gas trans is wide ratio, the diesel trans is close ratio.. if you search this forum you will find where the ratio's have been posted for each version.

If you are presently running a 4 speed you will need to also get the 5 speed adapter plate that bolts to the back of the engine or the 5 speed will not bolt up, and NO the 460 adapter plate will NOT bolt up to the 6.9 diesel [tried one of ever combination possible to make the gas trans work, ended up buying a diesel trans, damn!!]

You will also need the 5 speed flywheel and clutch and throwout brng. [WTH, it's only money, right?]

Been there, done that , in spades. Now have a sweet gas trans 5 speed with wide ratio and need a front case to make it all work. My plan "was" to use the wide ratio with a Gear Vendors and have the gear range with 9 speeds that I wanted..... Ohhhh well..... next!
Grant...

 

[tonkadoctor]

Tanya, we know you can swap a starter so now it's time to move up and rebuild a tranny.

Everything I see posted here by everybody else is correct and I can't add too it.

As far as the ZF6 conversion, it can be done but it's more than just swapping the tranny. Input shaft splines are different and IIRC the output shaft is also. The tranny is physically larger, heavier and slightly longer. The six speed uses a thinner engine adaptor, Need different bellhousing bolts, different clutch center section,, different slave cylinder, clutch fork and shifter, relocate the transmission crossmember and install a tranny cooler like is on automatics...And prolly a few other things.

Benefit is getting one more usable gear and a slightly higher overdrive, .72 vs .77

Time and money and it can happen but if downtime is a concern, swap in a good diesel zf5 and be done with it in a day.

 

[typ4]

Swap

I had a 460 bolted to my diesel trans, no it isnt a bolt in but for those interested I can post the pic again.

 

[G. Mann]

I had a hard look at doing a ZF6 swap before I committed to the ZF5 and came up with $$$$ numbers that were scary. Every ZF 6 I found was very spendy, plus all the "other parts" needed to make it work didn't balance out for the net gain, for me.

I did the numbers $$ wise on using a ZF 5 PLUS a Gear Vendors and came up with much more usable ratios by having the Gear Vendors to split gears with and then a final "overdrive , overdrive" of the ZF5 plus Gear Vendors final.

My goal is to work the engine in it's sweet spot as much as possible and suck as much work and life out of it as I can while getting the best mileage.

Total dollars out for a ZF5 plus a Gear Vendors is still less [by my best calculation] than it would have cost me for a ZF6 and I end up with 9 forward speeds instead of 6... all good in my book.

 

[Cheaper Jeeper]

.....If you are presently running a 4 speed you will need to also get the 5 speed adapter plate that bolts to the back of the engine or the 5 speed will not bolt up....

This may be true for some years but not all. I replaced the T-19 in my '86 with the ZF-5 from a '93 and it bolted right up to the adapter plate that was already in the truck.

.....You will also need the 5 speed flywheel and clutch and throwout brng.

This is certainly one option. Another option is to use the flywheel from your 4-speed, then buy the clutch disk (with a spring mounted center hub) and TOB for an 87 ZF-5, and the pressure plate for the earlier T-19. These can all be purchased from AutoZone for less than $200. If you need the part numbers I can post them for you....

 

[The Warden]

This may be true for some years but not all. I replaced the T-19 in my '86 with the ZF-5 from a '93 and it bolted right up to the adapter plate that was already in the truck.

I concur, having done a ZF swap in an '84. The clutch and flywheel are different, but the tranny bolts right up to the engine with no modifications to the engine or tranny (except for cutting off a location ear on the side of the tranny if your truck's turbo'ed, and even then, I believe that depends on the brand of the turbo). Moot point in regards to the original thread, though; looks like she's replacing a ZF with another ZF, not upgrading from a different tranny.

But...yeah, I wouldn't bother trying to swap a gas tranny behind the IDI unless you simply cannot find a diesel tranny, or you really want the wide gear ratio (which, with a diesel's power band, does more harm than good IMHO; early diesel T-19's had a wider ratio than later ones, and at least for my configuration, having narrower ratio gears was a BIG positive). As to the ZF6, I can't really add to what the others have said. An OD unit will give you 10 gears (although some may overlap? And, that might be a fair argument for a wide-ratio tranny, with also having the gear splitter) and double-overdrive, instead of 6 gears with essentially the same OD gear. And, after all's said and done, it'll cost less as well.

Just my (somewhat jumbled) $.02...hope it helps a bit

 

[G. Mann]

Gear Vendors only give you 9 gears with a ZF 5.. neither the wide ratio or the close ration ZF 5 will give you the 15 mph necessary to run the pump to split low/second so you lose one split ratio giving you 9 speeds... FWIW..
Grant...

 

[The Warden]

Oh, okay; didn't realize that GV had a minimum engagement speed. I never paid much attention to them; I'd rather have a U.S. Gear unit that can be used in 4 wheel drive