Ok, so my auto tranny decides to crap out on my again. This is about the third time since i have had my jeep an i am kinda sick of it. Some say cause its such a weak tranny with 35's, but who knows the real reason. Anyways, instead of having it torn apart for $300 just to find out what is wrong with it, i figured i could upgrade at the same time. What would be involved in swapping in a tf 999 or maybe a 727?? Maybe just get an adapter and then bolt it in? anything i would need to change?? :confused:

thanks :beer:
nick

the tf 998 and 999 are simply lockup versions of the 904,no real strength advantage.

either wich way,the 4 cyl has a different bellhousing pattern than the 4.0,4.2 and AMC v8s,so a 999 or 727 from behind one of them is not gonna swap.

chrysler used the 904 in v8 powered cars,so the best thing to do is rebuild the 904 with v8 internals. you can spend a bunch of $$ on it if you want to,and get kevlar clutches,bands,and other internal mods. call around to some tranny shops that specialize in building trannies for race cars and such.

there are plenty of guys running mildly built 360s in front of a beefed up stock 904/d300 in 80s cjs :)

904/999/727 are all different trannies. The 904 came behind 4cyls, 999 was 6 cyl and a few V8's, and the 727 was for V8's.

A 999 is plenty strong for 6cyl and most V8's.

the reason that i was thinking about swapping is because i didnt know if the 904 would be strong enough for 35's. From when people have been telling me I guess it is, so I guess I will just have them rebuild it and vent it and hope it doesnt happen again...

thanks
nick

WHat is happening when you are blowing up your tranny? Overheating? Complete failure?

What are the specs of your rig???


I have a 999 in my 94 YJ. I ran full width 60/70 and 40" TSL's. That tranny has never once given me a problem. I have a deep tranny pan, cooler, remote filter and gauge.

This time it is just making a noise, but AAMCO said that it was on its way out. Last time it would not go in reverse, when it did it would stall. Other times it would not shift.
its a 95 yj, 4banger, 904, 231. 30/44 with 4.88's and 35x12.50 swampers.
I have a shift kit, remote filter, larger cooler and a gauge. So it is not overheating.
I run mud, but I change the fluid after I go mudding, but maybe there is still stuff getting caught in the tranny. I havent vented it yet only cause aamco wouldnt do it last time they worked on it. But knowing its not vented I havent gone near a lot of water.
My reasonings for it failing was either because it wasnt a strong tranny or the mud was getting to it. From when I have been reading it might be the mud getting to it...